1. Plant Required Elements:
There are approximately 15 essential elements required by plants. Carbon, hydrogen, and oxygen can be synthesized chemically from air and water, while the remaining elements must be obtained from the soil. These can be roughly divided into three categories:
1. Primary Elements: Primarily nitrogen, phosphorus, and potassium, these are essential for plant development and growth, and are relatively scarce in soil. 2. Secondary Elements: Calcium, sulfur, and magnesium. 3. Micronutrients: Other elements required in smaller quantities that can usually be met by soil.
2. Nitrogen, Phosphorus, and Potassium
: 1. Nitrogen: A major component of plant leaves, primarily forming protoplasm (protein), promoting dense, dark green leaves. {Excess}: Leads to excessive stem and branch growth, resulting in overly robust and dense leaves, affecting flowering and fruiting time and quality. {Deficiency}: Causes weak stems and branches, pale yellow and smaller leaves that easily fall off. {Timing}: From seedling stage to before flowering; gradually reduce dosage before flowering. 2. Phosphorus: Primarily absorbed by plants as phosphate, it is a major element in the formation of flowers and fruits, mainly used during cell division and nucleus synthesis. Excessive potassium: Leads to excessive flowering and fruiting, potentially causing the stems and branches to collapse if they cannot support the weight. Insufficient potassium: Resulting in fewer and smaller flowers and fruits, poor quality, and premature drop. Timing: Gradually increase the amount before flowering. 3. Potassium: Primarily absorbed by plants in the form of potassium oxide, forming a major component of plant stems and branches. Excessive potassium: Leads to dense branches, shortened internodes, slow growth, and yellowing leaves. Insufficient potassium: Resulting in poor resistance, including cold, drought, and disease. Lower leaves are prone to falling off and wrinkling. Timing: Apply evenly to all stages of plant growth.
3. Fertilizer Types and Characteristics
1. Powdered fertilizer: Powdered fertilizer is directly scattered on the medium or buried in holes. This type of fertilizer is commonly used in open-air garden nurseries. Because it is evenly dispersed in the medium, it slowly reaches the roots for absorption, resulting in a gentle and uniform effect. However, it continues to release nutrients even during periods of growth stagnation. Examples include bone meal and compost. 2. Granular or stick-shaped fertilizers: These have a longer but slower effect, and the nutrient release is overly concentrated, making it difficult to stop fertilizing. For example, nutrient sticks. 3. Diluted fertilizers: The most common and fastest method. They offer the dual benefits of fertilizing and watering, and the "small, frequent applications" approach allows for strict control of the amount applied, with the option to stop fertilizing immediately during rest periods. However, this method requires consistency.
4. Fertilization methods
: 1. Applying as a "base fertilizer": a. This involves directly mixing the fertilizer into the soil medium, allowing nutrients to be gradually released to the plant roots. b. Suitable timing: Initial planting, repotting, transplanting, and seasonal fertilization. c. Suitable fertilizers: Primarily slow-release fertilizers, such as compost, chicken manure, fish bone meal, soybean cake, and other organic fertilizers. d. Application method: Apply fertilizer in layers of soil and fertilizer, avoiding direct contact between the fertilizer and the roots to prevent fertilizer burn. e. Other precautions: For perennial woody plants, fertilizer should be buried in spring and autumn within the area of ​​the canopy projection. 2. Fertilizing in the form of "topdressing" a. Nutrients applied during the growth and development of plants are called topdressing. b. Timing of application: Provide the nutrients needed by the plant at any time during the growth process. c. Fertilizers used: Mainly "fast-acting" chemical fertilizers containing the three elements, such as Flower Treasure, liquid fertilizer, etc. d. Other precautions: Dilute and apply in the form of "small amounts frequently"; avoid direct application to leaves or flowers. 3. Fertilizing in the form of "foliar application" a. Spray diluted fertilizer directly onto the plant leaves, which can be absorbed directly by the leaves and replenish nutrients quite quickly. b. Applicable fertilizers: Inorganic fast-acting chemical fertilizers. c. Precautions (1) Must be quite diluted to avoid fertilizer burn. (2) Suitable for early morning, late evening or cloudy days. (3) Avoid application when the sun is high.
5 Commonly Used Media
1. Soil Soil generally refers to soil directly taken from outdoors, or a medium formed from the residue of decaying plant stems and leaves. The biggest advantage of this medium is that it is easy to obtain, plentiful, and inexpensive, making it the most suitable medium for planting large quantities of robust plants. However, its disadvantages are that the quality of soil varies greatly, is difficult to control, and often contains various bacteria, harmful insects, or even eggs hidden within. This can easily disturb or damage the plants, leading to disease or death. Therefore, if the plants being cultivated are extremely valuable, ordinary soil is not suitable as a medium. If it must be used, it must be pre-treated. First, select the soil to remove unnecessary impurities, then sterilize it by direct sunlight or by sprinkling a small amount of lime before use. 2. Peat moss is one of the most well-known and widely used horticultural cultivation media. Its raw materials are mainly collected from mosses and algae in temperate regions' swamps or wetlands. The fibers accumulated after the plants die and decompose are dried, processed, sterilized, and made. Taiwan does not produce raw materials locally, and considering the cost, it is not necessarily cost-effective to make them in-house. Therefore, it mainly relies on imports, and only a few larger flower growers process and use imported raw materials themselves. Peat moss has many advantages that general soils lack, mainly because it is clean, lightweight, of good and stable quality, and has a wide range of uses. It is suitable for most plant species and for plants at various growth stages. However, peat moss also has some disadvantages. For example, peat moss does not absorb water easily when used for the first time, and it tends to harden when completely dry, making it difficult to absorb water. In this case, you can rub it into finer particles by hand or soak it in water to help it absorb water more fully. In addition, because peat moss is lightweight, it is not suitable for planting taller plants. If it is mixed with sand or soil to increase its weight, it can prevent large plants from collapsing. 3. Perlite: Perlite is a common growing medium in horticulture. It is granular in shape and, due to its pure white color and light weight, resembles granular polystyrene or pristine snow, making it popular among horticulturists. In terms of physical properties, its drainage and aeration are better than peat moss, so it is often used in combination with peat moss. Perlite particles come in different sizes, and the timing of their use depends on the actual needs. Generally, when mixing with other media or using large quantities, larger perlite particles better highlight its physical properties and are less prone to loss. For cultivating more delicate horticultural plants or potted plants, smaller perlite particles can be used. Furthermore, perlite also has a decorative function; covering the surface of the medium with a layer of fine perlite not only covers less conspicuous areas of the medium but also helps prevent insects from entering the medium and avoids fertilizer odors from spreading into the air—truly a win-win situation. 4. Vermiculite: Vermiculite is yellowish-brown with a metallic luster. The particles are small, about 3-5 mm cubic meters, and lightweight. It's a cultivation medium with physical properties between peat moss and perlite. Its manufacturing process also involves sterilization, so it's safe to use. It's often used as a mix with peat moss, offering good aeration and water absorption. However, the particles are relatively large and don't adhere well to each other, making it unsuitable for effectively securing plants and also unsuitable for sowing. 5. Tree Fern Shavings: Tree fern shavings are a medium made from the dried, aged fibers of ferns (such as the tree fern). Tree fern shavings themselves are black, fibrous strips. After processing and sterilization, they become block or loose cultivation media. This medium's physical properties are very similar to dried instant noodles—dry, crisp, and with good drainage and ventilation. However, unlike instant noodles, it doesn't absorb water and swell, making it very durable and ideal for orchids or climbing plants. Its disadvantage is that nutrients don't adhere easily, increasing the difficulty of fertilization. 6. Sphagnum Moss: As the name suggests, sphagnum moss is made from the fibers of moss plants. Due to its excellent water absorption, much like a sponge, and its fibrous structure, it doesn't easily disperse. Therefore, it's often used in combination with tree fern fiber to cultivate orchids, compensating for the shortcomings of tree fern fiber, such as the difficulty in nutrient adhesion and fertilization. Furthermore, it's particularly suitable for fixing plants in uneven terrain; for example, many landscaping enthusiasts often plant orchids on tree trunks, where sphagnum moss and rope are ideal for securing them. 7. Gravel: Gravel is generally obtained from riverbeds or streamsides, or as leftover material from construction. It's not difficult to obtain. Its physical characteristics include high weight, good heat absorption and dissipation, and strong drainage. Gravel particles come in different sizes; larger particles are generally called gravel, while finer particles are called soil. Gravel (soil) is often used for special needs, such as planting drought-tolerant plants (peanuts, cacti) or fixing large plants. Sand and gravel (soil) are highly leached, making fertilization difficult. This can be overcome by using small amounts of fertilizer frequently or using long-acting fertilizers. 8. Other materials
such as chemical artificial materials, polymers, and foamed stone are sometimes used as cultivation media for hydroponics, sometimes as fillers, and sometimes purely for aesthetic purposes.　
6. How to Choose a Growing Medium
1. Differentiate by Purpose
1.1 Garden Nurseries
Garden nurseries generally have a large planting area, so using a completely sterile growing medium could be quite expensive. Unless financially feasible, they usually use natural soil for cost-effectiveness. Since soil is generally quite sticky, it easily hardens after watering and drying. Therefore, other used growing media, such as peat moss, perlite, and even some sand can be mixed in to reduce the stickiness of the soil.
1.2 Potted Plants
Plants planted in pots are usually more delicate, or they are planted intentionally to beautify certain places. Therefore, the growing medium used is usually a clean, sterile medium, such as peat moss, perlite, vermiculite, etc. The mixing ratio depends on the type of plant. Larger potted plants can be mixed with some soil or sand to increase their center of gravity and enhance their stability.
1.3 Hydroponic cultivation
Hydroponic cultivation often uses specialized hydroponic tools and growing media purchased from flower markets. Some of these materials are quite expensive, but they are very convenient to use. Since the growing media directly absorbs the nutrient solution, there is no need for frequent watering and fertilization. In addition, it can be grown at home and does not require a large area, so it is quite popular among urban dwellers.
2.
Different plant species require different growing environments. Therefore, to create an environment conducive to plant growth and development, it is essential to select the appropriate cultivation medium based on the plant's characteristics. As the saying goes, "A skilled craftsman must first sharpen his tools," and "A good start is half the battle." Therefore, for those who enjoy gardening, understanding the characteristics of the plants they wish to grow and carefully selecting the cultivation medium accordingly is a fundamental skill for beginners. The following are some examples for reference:
2.1 Common outdoor nursery flowers, such as globe amaranth, African impatiens, zinnia, sunflower, etc., can be sown or transplanted using a mixture of peat moss, perlite, or vermiculite. Mature plants can be planted directly in soil when transplanting.
2.2 Drought- and heat-tolerant plants, such as cacti or succulents, are best suited for well-drained sandy soil.
2.3 Plants with good water tolerance, such as golden pothos, evergreen, Brazilian ironwood, or some edible leafy vegetables, can be grown using hydroponics.
2.4 Plants that prefer moisture but whose roots cannot tolerate waterlogging, such as orchids, are suitable for cultivation using tree fern fiber and sphagnum moss.
7 Watering Methods
1. Irrigation Method
a. Timing: Suitable for most plants. This method involves directly irrigating the medium, requiring little time.
b. Advantages: Direct, fast, and simple; it can also clean leaves with accumulated dust.
c. Disadvantages
c-1. It cannot fully saturate drier, harder media.
c-2. It often waters the stems, leaves, or flowers, which may damage some plants whose stems and leaves do not like moisture, and may
shorten the lifespan of the flowers.
d. Notes:
d-1. After watering, empty the excess water from the saucer at the bottom of the pot to ensure proper airflow through the drainage holes.
d-2. If the pot does not have drainage holes, tilt the pot to empty the water.
2. Soaking Method
a. Timing
a-1. Suitable for dry, hard, or clumpy media.
a-2. Suitable for semi-moist and fully moist plants, but for the former, the water basin should be removed after soaking to prevent root rot from prolonged soaking. c
a-3. Suitable for plants whose stems and leaves are susceptible to waterlogging, such as gloxinia and African violet
. b. Advantages
b-1. Allows for thorough wetting of the medium
b-2. For plants that require long-term moisture, this method eliminates the need for watering
c. Disadvantages
c-1. Requires a longer time
c-2. Medium may run off
8. Plant Light Requirements
1. Full Sun
a. Definition: Illumination where the plant receives sunlight throughout the day
b. Location: Outdoors in an unshaded area or on a south-facing windowsill (since the sun moves east-west, placing it on a south-facing side avoids morning and afternoon interference), but moderate shading is necessary in summer.
c. Plant Types: Suitable for most flowering plants, such as: zinnia, cockscomb, coleus, bougainvillea, lantana, amaryllis, sunflower, rose, etc.
2. Partial Sun
a. Definition: Illumination where the plant receives sunlight for part of the day
b. Location: Outdoors or on an east-west facing windowsill with shading devices (e.g., shade netting) or on a partially shaded south-facing windowsill.
c. Plant types: Suitable for many indoor flowering and foliage plants, such as: African violet, gloxinia, impatiens, snake plant, poinsettia, chili pepper, small shrimp flower, croton, etc.
3. Bright
a. Definition: Close to light but not directly exposed to sunlight.
b. Location: Window sill without direct sunlight or near a transparent indoor window (within about 15 cm of the window) or outdoors with shade.
c. Plant types: Suitable for many foliage and flowering plants, such as: ornamental pineapple, peperomia, nerve plant, peace lily, schefflera, cyclamen, azalea, etc.
4. Partial shade
a. Definition: Moderate light intensity, but still clearly visible to the naked eye.
b. Location: Under sparse shade outdoors or near a window indoors (more than 30 cm from the window).
c. Plant types: Not suitable for many flowering plants, but suitable for some foliage plants. For example: ivy, dwarf coconut palm, snake plant, Brazilian ironwood, nerve plant, etc.
5. Shade
a. Definition: The light is relatively weak, but the text can still be distinguished by the naked eye.
b. Location: Under dense trees outdoors or indoors far from windows (more than one meter away) or indoors without windows.
c. Plant types: Not suitable for flowering plants, but few foliage plants can adapt. For example: ferns, nerve plants, Brazilian ironwood, evergreen plants, golden pothos, etc.
6. Darkness
a. Definition: Almost no light exists.
b. Location: Darkroom, cave, etc.
c. Plant types: Except for a few fungi, mosses, or plants in the budding stage (e.g., mung bean sprouts), most plants cannot survive or grow.
9. Plant Propagation - Air Layering
1. Applicable conditions: Air layering is suitable for plants with thick stems and lignification, such as: Brazilian ironwood, dragon blood tree, Dieffenbachia, etc.
2. Suitable time: Springtime is the best time to perform this method.
3. Air layering, also known as layering, is a method of propagating new plants without altering their original shape.
4. Steps:
a. Selecting branches: Select last year's lignified stems. The stems themselves must be healthy and free from pests and diseases; and they should not be too close to the base or tips of branches, otherwise the survival rate will be greatly reduced.
b. Ring-barking: Using a sterilized utility knife, ring-bark the selected area. The bark should not be too deep; the goal is to remove the epidermis without damaging the vascular bundles of the stem.
c. Rooting powder applied to the barked area promotes faster root development.
d. Wrapping the outer layer with a plastic bag: Take a suitable piece of plastic sheeting and secure the bottom with wire or other thin rope.
e. Medium filling: Fill the plastic bag with a suitable medium, preferably sphagnum moss, but other highly absorbent sponge materials are also acceptable, and add water.
f. Finally, completely wrap the plastic sheeting, securing the top with string or wire as well.
g. Keep the internal medium appropriately moist. Roots should develop from the ring-barked area in about two months.
h. Cut off the bottom and replant in the medium; the original mother plant can continue to grow new shoots from the cut.
5. A node or leaf is best located no more than 10 cm above the ring-barked area for better survival.
6. Avoid direct, strong sunlight for a higher survival rate.
10. Plant Propagation - Division Method
1. Suitable Conditions: Plants that readily produce lateral buds from the sides or nodes of the main stem, such as cacti and succulents; or plants that produce many offsets from the mother plant's bulb, such as daffodils and amaryllis.
2. Timing: When the meristematic tissue is sufficiently self-sufficient, or during the spring plant revival period.
3. Steps:
a. Selecting Offshoots: Select healthy mother plants that have already produced numerous offsets, ensuring the offsets themselves are capable of independent survival.
b. Separating Offshoots: Using a sterilized blade, separate the offset from the mother plant. When cutting, try to maintain the structural integrity of the offset while avoiding excessive damage to the mother plant. Some offsets, such as cactus offsets or amaryllis offsets, can be twisted off the mother plant by hand, thus avoiding injury from an improperly sharp blade.
c. Replanting: The removed bulblets can be replanted into the medium. Insert the base of the bulblet into the medium. If the wound on the bulblet is large, wait for it to dry before planting to avoid rotting.
d. Maintaining moisture: Keep the medium moist, avoiding waterlogging.
4. If the offshoot is a lateral bud, simply bury the bottom shallowly in the medium; if it is a bulblet, bury it completely in the medium.
5. After the bulblets separate and become independent, they will re-root in about one month, but it usually takes 1-2 years to grow to the size of the parent plant.
11 Plant Propagation - Seed Method
1. Applicable Situations:
a. Mass Propagation: Seed propagation can cultivate a large number of seedlings at once, achieving the purpose of mass propagation; this method is often used for leafy vegetables, creating a large amount of economic value.
b. Complete Observation: The entire growth cycle of a plant can be observed, starting from the seed; beneficial for teaching or research purposes.
c. Lower Cost: Planting from seeds is usually less expensive than purchasing mature plants.
2. Timing: Propagation can be done year-round, depending on the plant's condition; most plants are best propagated by spring sowing.
3. Steps:
a. Seed Selection: If collecting seeds yourself, choose mature and healthy seeds; if purchasing seeds from branches, ensure they have been stored for a considerable time or show signs of mold or spoilage, avoiding such purchases.
b. Seedbed Preparation:
c. Sowing: Sowing methods vary depending on seed characteristics. Based on shape and size, seeds can be categorized as follows:
c-1. Granular: For example, asparagus fern, legumes, etc. These plants have seeds that are large enough to be handled by hand, and the plants are usually quite large, making them suitable for 'spot sowing', with seeds spaced a few centimeters apart.
c-2. Needle-shaped: Mostly found in Asteraceae plants, whose seeds are often needle-shaped. 'Spot sowing, broadcast sowing, or insertion sowing' methods can be used, directly inserting the seeds obliquely into the medium.
c-3. Powdered: These seeds are extremely small, such as those of snapdragons and impatiens. Because of their small size, these plants are difficult to handle, so "casting" is more appropriate, directly scattering the seeds onto the surface of the growing medium.
Based on their physiological characteristics, they can be further categorized as follows:
c-4. Covered with soil or not: Most seeds exhibit some phototropism, so a light layer of growing medium can be laid on top to cover them. Larger seeds usually require more soil covering to promote germination.
c-5. Soaked (or not soaked): Seeds with difficult-to-peel seed coats can usually be soaked in water before sowing to soften the seed coat, such as legumes.
c-6. Seed coat removed (or not removed): For some plants with particularly hard seed coats, such as asparagus fern, custard apple, and sage orange, it is best to technically remove the seed coat before planting. Otherwise, allowing the buds to sprout on their own may take several weeks or even a month.
d. Keep the medium moist: Water daily to keep the medium moist, avoiding watering with a watering can to prevent seed loss; bottom soaking or misting is best. If necessary, cover the top of the container with plastic sheeting or transparent glass to maintain humidity.
e. Place in a cool, well-ventilated place, avoiding direct sunlight.
f. After germination, immediately move to a bright location. Some plants, such as sunflowers, even require immediate direct sunlight; otherwise, they are prone to etiolation (leggy growth), turning into a plate of bean sprouts.
4. After germination, adjust the orientation of the seedling pot as needed to prevent the seedlings from growing towards the light, thus ruining their shape.
5. Plants grown by sowing are generally outdoor plants, mostly flowering plants; this method is less common for indoor plants or foliage plants.
6. Once the germinated seeds reach a certain height, it is best to transplant them into small plastic pots to provide a better growing environment.
7. Sowing is the most traditional and widely used method of plant propagation, and also the easiest; however, it is not necessarily the one with the highest survival rate or the most economic value, depending on the plant species, technique, and environmental factors.
12 Plant Propagation - Layering
1. Applicable conditions: Climbing plants or trailing vines, because their branches are long and flexible, are very suitable for propagation by layering.
2. Timing: Can be done in all seasons. Spring and autumn are the best seasons.
3. Steps:
a. Select branches: Branches that are beyond the normal ornamental range of a potted plant or of a certain length sufficient for layering are suitable. The branches should be healthy, free from pests and diseases, and have reached maturity; overly tender branches are not suitable.
b. Prepare the medium and another plastic pot: Prepare another plastic pot and mix the appropriate growing medium into it.
c. Layer the branch and make a wound with a sharp blade; the wound should not be too deep, causing the branch to break off from the plant.
d. Bury the wound about 3 cm below the medium in the new pot.
e. Secure the branches to the pot using U-shaped wire and clips.
f. Water and keep the medium moist.
g. Place in a cool, well-ventilated area.
h. Roots will develop in about 1-2 months. After rooting, the branch can be separated from the mother plant to grow as an independent individual.
4. If the plant's branches are too long and obstruct the view, consider propagating the excessively long branches by layering.
5. Layering takes longer and is more troublesome than cuttings, so it is less commonly used.
13 Plant Propagation - Division
1. Applicable conditions: Plants that grow in clusters, with meristematic buds constantly emerging from the bottom, forming a group; for example: African violet, Syngonium podophyllum, Gloxinia, Maidenhair fern, etc.
2. Timing:
a. Spring and autumn are the best seasons.
b. When the plant's offshoots are vigorous and growing, forcing the mother plant to grow in a compressed space, resulting in a disordered plant shape.
3. Steps:
a. Selecting a plant: The plant should be healthy and free from pests and diseases, and the offshoot should be mature enough to survive independently.
b. Removing the mother plant: Remove the mother plant from the medium or pour it out of the pot, and gently tap (shake) the plant to separate the medium from the roots.
c. If necessary, locally clean the roots to clearly reveal the connection between the offshoot and the roots.
d. Use a sharp knife or your hands to directly separate the offshoot from the roots of the mother plant, trying to keep the stem of the offshoot connected to part of the roots to avoid the stem breaking off completely. If it breaks accidentally, you will have to consider leaf propagation instead.
e. Replant the offshoot in a new pot or medium.
f. Water and keep the medium moist. Before roots develop, you can reduce the water supply, and then resume normal watering after roots have grown.
g. Place it in a well-ventilated place and avoid direct sunlight.
h. Roots will develop in about 2-4 weeks, and normal growth will resume.
4. Propagation by division is faster, but the number of plants can never be mass-produced.
17 Introduction to Chemical Fertilizers
Chemical fertilizers, also known as "inorganic fertilizers," are fertilizers made from non-living organisms or inorganic compounds and minerals. According to their composition, there are four types: single-element fertilizers, compound fertilizers, special fertilizers, and micronutrient fertilizers. 1. Single-element fertilizers Single-element fertilizers refer to fertilizers that contain only one of the three elements. They can be used separately according to the needs of plants, or they can be mixed and prepared with other fertilizers. Among them, superphosphate lime can be used as a base fertilizer or as a quick-acting top dressing.
(1) Nitrogen fertilizers: such as urea, ammonium sulfate (ammonium sulfate), ammonium nitrate, ammonium chloride, etc. (2) Phosphate fertilizers: superphosphate lime (superphosphate) (3) Potassium fertilizers: such as potassium chloride, potassium sulfate, etc. The above single-element fertilizers are the agricultural fertilizers that farmers generally use for rice, vegetables, and fruit trees. 2. Compound fertilizers refer to fertilizers that contain two or more of the three elements. Currently, all fertilizers sold are in small packages. When purchasing, pay special attention to the ingredient ratio indicated on the packaging bag. In terms of use, they can be divided into solid fertilizers that can be stored or water-soluble fertilizers. (1) Solid fertilizers that can be stored: such as Taiwan Fertilizer Compound Fertilizer No. 1, No. 2, No. 3, No. 5, No. 7, No. 12, No. 17, No. 27, No. 36, No. 39, No. 43, etc., are fast-acting fertilizers and can be used as top dressing. Taiwan Fertilizer long-acting fertilizer, Magic Fertilizer, Immortal Fertilizer and other slow-acting fertilizers are suitable for use as base fertilizer. (2) Water-soluble fertilizers have high solubility and are suitable for use as top dressing. Such as Taiwan Fertilizer fast-acting fertilizer, Flower Treasure, Fengduole, etc. These are safe and effective as long as they are diluted according to the indicated ratio. 3. Special fertilizers refer to fertilizers made of special ingredients such as lime, magnesium, and silica. They are generally used to improve soil quality, such as sulfur powder, magnesia lime, calcium element, etc. 4. Micronutrient fertilizers refer to fertilizers containing trace elements other than the three major elements (metal, phosphorus, and manganese), such as copper, iron, boron, zinc, magnesium, and chlorine. Magnesium, manganese, and boron are relatively easy to be deficient in.
18. Photosynthesis is
the process by which plants use light energy to synthesize organic matter from inorganic substances such as carbon dioxide and water, releasing oxygen.
The organic matter synthesized in photosynthesis is the main source of matter and all the energy for plant growth, and also the source of organic matter and energy for other organisms that directly or indirectly depend on plants. Light-powered and chemoautotrophic bacteria can perform part of the photosynthetic process and also synthesize organic matter, but in extremely small amounts. Plants on Earth synthesize nearly 200 billion tons of organic matter annually through photosynthesis, while simultaneously fixing 3 x 10²¹ joules of solar energy, equivalent to 10 times the total energy consumption of humankind. Coal, oil, and natural gas buried in strata evolved from organic matter formed by ancient plant photosynthesis. Photosynthesis releases O₂ and fixes CO₂, causing O₂ to accumulate in the atmosphere and CO₂ levels to decrease.
Photosynthesis is of great significance to Earth's evolution, biological evolution, the maintenance of the current atmospheric environment, and human life and production. Besides exploring and utilizing photosynthesis from various perspectives, people also simulate some of its processes to study the mechanism of photosynthesis and its biomimetic applications.
19. Roots (
the underground part of the vascular plant axis) primarily function for anchorage and absorption, while also synthesizing and storing organic matter and carrying out vegetative reproduction.
Roots do not grow leaves or flowers. Although they branch like stems, the origin of these branches (lateral roots) differs. Algae and bryophytes do not have roots. The most primitive ferns, such as *Pteris vittata*, *Messiella foenum-graecum*, and the earliest ancient terrestrial fossil *Lycopus lucidus*, also lack true roots, possessing only rhizoids with absorptive functions on their underground rhizomes. Most extant ferns, gymnosperms, and angiosperms have true root structures.
109. Plants' light requirements:
We often see descriptions of sunlight environments in books: full sun, partial shade, and shade. Here's an explanation of the terms: Full sun: Under the blazing sun without any shade. Direct sunlight from sunrise to sunset. For example, the flowerbeds at the Sun Yat-sen Memorial Hall. Partial sun: Receives direct sunlight for some time of day and shade for others. For example, balconies that receive direct sunlight, or places near tall buildings that are sometimes shaded. Shaded areas: Relying entirely on diffused sunlight throughout the day. Primarily indoor locations. Most plants can tolerate full sun or partial sun. Plants that can tolerate shade are only suitable for indoor decoration.
110 Sunlight and Leaves
Many foliage plants have white patches on their leaves, such as golden pothos, white butterfly arrowhead, and ivy. Or their leaves are golden-green, such as golden fig and golden dewdrop. When they don't receive enough light, the white patches on the white-spotted plants will disappear, and plants that originally had golden leaves will grow dark green leaves. Conversely, more light will make their white spots more numerous and pronounced, and their golden color brighter. Sometimes, excessive sunlight can also harm the plant, most obviously in its leaves. We often see scorched or withered yellow patches on the leaves, indicating excessive sun exposure.
111 Soil:
Soil and plants have different water retention, moisture retention, aeration, and drainage properties. The size and weight of the soil also play a role. Therefore, we must use a combination of leaf mold, sphagnum moss, river sand, tree fern fiber, field soil, vermiculite, and perlite to achieve the soil properties required by the plant.
112 Sunlight and Flowering
Plants: Generally speaking, flowering plants have a relatively high demand for sunlight. Sunlight promotes flowering. Insufficient sunlight results in poor flowering. Therefore, you will find that plants that can be kept indoors in low-light conditions are generally foliage plants. Flowering plants are rarely kept in shady places.
113 Sunlight and Plant Shape
Sunlight is the source of energy for plants. When a plant doesn't get enough light, it thinks it's because it's not tall enough and the light is being blocked by others, so it will grow as tall as possible to get sunlight. The plant will grow tall and slender, the distance between leaves will be longer, there will be fewer branches, and the plant shape will appear more slender. When choosing plants, especially flowering plants, we prefer plants that are short, with many branches, and look short and dense. This is because such plants are stronger, look healthier and more vibrant, and produce more flowers. Short plants are more suitable for use in flower beds. More importantly, insufficient sunlight will cause poor flowering, and a tall and slender plant shape is a characteristic of insufficient sunlight. So, from this, you can learn a technique for choosing flowering plants: short and dense plants with many branches; tall and slender plants indicate that the plant has not received enough light, is weaker, and will not flower well.
114 Plants and
Water: Water is the driving force behind plant growth, commonly known as "watering for three years," ensuring long-lasting lushness. Generally, foliage plants prefer moist conditions, so the amount and timing of watering should be carefully considered: in summer, water in the morning or evening, but avoid watering at midday under the hot sun; the opposite applies in winter. Spraying is the best watering method for foliage plants, not only keeping the leaves moist but also removing dust (except for leaves with fuzz). All plants need water. However, overly moist soil can easily cause root rot, and poorly drained soil exacerbates this problem. Different plants have vastly different water requirements. Generally, succulents with thick leaves, cacti, and plants with thick rhizomes are more drought-tolerant because they store a large amount of water. Plants with thick waxy coatings and small leaves are also drought-tolerant because they transpire less water. Generally, the more drought-tolerant a plant is, the less tolerant it is of wet conditions, and the more demanding it is of drainage in its growing medium. Seasonal factors also greatly influence water requirements. Because plants are in their growth period during spring, summer, and autumn, especially summer, their transpiration rate is high, and their water demand increases. Many plants need daily watering in summer, but in winter they only need to be watered when the soil is completely dry. If daily watering is not possible, water can be poured directly into a plastic pot, and a plant placed on top can be placed to support the pot, preventing the pot from directly contacting the water.
115 Advantages of Seed Propagation
1. A large number of seedlings can be obtained in a short time. 2. Seedlings have more developed root systems and longer lifespans. They can be used as rootstocks for grafting flowering or fruit trees. 3. Hybrid breeding must use seed propagation to obtain superior traits compared to the parent plants.
116 Disadvantages of Seed Propagation
1. The time from sowing to plant maturity and flowering is longer. 2. In the propagation of heterozygous and hybrid varieties, the traits of the parent plant cannot be preserved.
117 Environmental Conditions for Seed Germination
Water: With water, enzymes can be active, and the nutrients stored in the seed can be hydrolyzed and utilized. Oxygen: Seeds need oxygen to begin respiration and become active. Overwatering during sowing can cause seeds to rot due to oxygen deficiency. Temperature: The optimal temperature for seed germination varies depending on the plant's origin. Generally, temperate plants thrive best at 15-20 degrees Celsius, while subtropical and tropical plants thrive best at 25-30 degrees Celsius. Light: After sowing, consider the plant's light requirements to determine whether to cover the seeds with soil. Small seeds, with limited nutrient reserves, often lack the nutrients to support germination at the surface and are more phototropic.
118 Seed Dormancy:
Seeds are viable but fail to germinate even under suitable conditions. This can be divided into seed coat dormancy and internal dormancy (physiological). Methods to break dormancy: 1. Seed coat damage treatment: For seeds with hard seed coats, you can use sandpaper to scratch the seed coat or a knife to cut it, but be careful not to damage the inside of the seed. 2. Hot water treatment: Seed coats are impermeable to water. Soak the seeds in water for about a day until they swell, then remove them for sowing. 3. Moist-cold stratification treatment: Mix seeds with an equal to three times their volume of moist sand, vermiculite, or sphagnum moss, place in a plastic bag, and keep at a temperature of 0-10 degrees Celsius for 1-4 months, then remove and sow. (Seeds of temperate flowering trees such as peach, pear, maple, and some pine species)
119. The suitable sowing time
, depending on climatic conditions, is generally spring and autumn. Herbaceous flowers with weak heat tolerance should be sown in autumn, while those with weak cold tolerance should be sown in spring. Please refer to the herbaceous flower sowing table for species.
120.
Commonly used sowing media include soil, peat moss, vermiculite, perlite, fine sphagnum moss, or mixtures of these materials.
121. A good sowing medium should meet the following conditions:
1. Uniform and fine particles to prevent seeds from being lost through gaps. 2. Free from pathogens, insects, or weed seeds; preferably sterilized. 3. Contains little or no nutrients. 4. Loose texture and good aeration. 5. It has good water retention capacity, and water can move within it through capillary action.
122.
Soil Covering: The standard amount of soil covering the seeds is 2-3 times the weight of the seeds, and the thickness is twice the weight of the seeds. Seeds that require light to germinate should not be covered with soil. To prevent seedlings from falling over, soil can be covered when the radicle begins to grow.
123. Tiny Seed Sowing Method
in Pots: Cover the bottom 1/3 of the pot with broken tiles or stones, fill the pot with soil, lightly without pressing, use a piece of wood to push away excess soil, and then use a pressing board to lightly press the soil down to about 1 cm below the rim of the pot. Spread clean, fine soil that has been sifted and does not contain decaying leaves or other organic matter on the surface, and evenly scatter the fine seeds. After sowing, press down with a pressing board to ensure close contact between the seeds and the potting soil.
124. Reasons for Seeds Not Germinating:
1. Improper or prolonged storage of seeds, resulting in loss of germination ability. 2. Seed dormancy conditions not overcome. 3. Inadequate temperature conditions in the sowing environment. 4. Tiny seeds are washed away during watering. 5. Unclean soil leads to seed mold and rot. 6. Overly thick soil covering. 7. Seeds are eaten by rats or cockroaches.
125 Post-Sowing Management
After sowing, place the seed box in a cool, shaded place without direct sunlight. The box can be covered with glass or plastic sheeting until the seeds germinate. For seeds requiring dark germination, cover with a layer of black cloth or newspaper. The number of days required for germination varies depending on the species; generally, it takes about 1-2 weeks for herbaceous flowers and about 1-2 months for woody plants. After the seedlings emerge, apply diluted liquid fertilizer and gradually move them to a brighter location in preparation for transplanting. If the seeds have not germinated within the expected period, dig them up for inspection. If the seeds become soft, rotten, or have a foul odor, they have died.
126 Seed Storage
The most important conditions for preserving herbaceous flower seeds are low temperature, dryness, and airtight sealing. Tea canisters and candy jars are excellent storage containers. First, line the bottom with a desiccant, then add the seeds, and seal the opening with a plastic bag. They can then be stored in the refrigerator for a long time. However, avoid frequently taking the seed container out, as temperature fluctuations can severely damage the seeds. Purchased seeds are usually already dried and sealed. If you are not sowing them immediately, do not open the packaging; store them directly in the container. If you have harvested the seeds yourself, wait until they are completely dry before storing them.
127. Conditions for Rooting Cuttings:
The branches used for propagation by cuttings are called cuttings. The ease with which cuttings root depends mainly on their physiological condition and environmental factors.
128. Physiological Condition of Cuttings:
Generally speaking, younger branches closer to the terminal bud root more easily, and growing branches root more easily than dormant branches.
129. Environmental Conditions for Cuttings:
Environmental conditions include the influence of the cutting medium, temperature, humidity, and light. Even the best cuttings will not have a satisfactory survival rate if they are not placed in suitable environmental conditions. During the cutting process, since roots have not yet developed, high air humidity should be maintained to prevent water from evaporating from the leaves. For large-scale cuttings, misting is necessary to increase humidity; for general households, covering with plastic sheeting or bags is sufficient. Remember, if a cutting wilts even once during the cutting process, root development will be significantly affected. Moderate shading can reduce water evaporation and prevent wilting. Generally, shading should be around 50-80%. The temperature range varies depending on the plant species, but a bed temperature of 20-25°C is generally most suitable. A good temperature environment should have a high soil temperature and a low air temperature. The cutting
medium
refers to the material used for root development, including soil, sand, and other materials. A good medium should meet the following conditions: good aeration and drainage; clean, sterile, and free of pests and diseases, and weed seeds; and free of nutrients, as cuttings cannot utilize nutrients before root development and these nutrients can actually promote pathogen growth. Commonly used media include soil, sand, vermiculite, perlite, sphagnum moss, tree fern fiber, and water.
131. Selection and Preparation of Cuttings:
Cuttings should be taken from healthy, disease-free mother plants. Generally, the more vigorous the mother plant, the faster the cuttings will root. Selection of Branches: Branches between green tender shoots and brown woody mature branches have a high survival rate and fast rooting speed.
Season: Cuttings are generally taken from spring to autumn. The quality of cuttings varies greatly depending on the time of year. For example, cuttings can be taken from robust young shoots that sprouted that year in summer (softwood cuttings), from semi-hardwood cuttings in autumn (semi-hardwood cuttings), or from dormant woody cuttings in winter (hardwood cuttings). Softwood cuttings usually root fastest, but the cutting bed should have good misting equipment. Hardwood cuttings are easy to manage, but rooting is slow; they often sprout before roots develop, causing the new shoots to die. Therefore, it is best to take cuttings in the early dormancy period.
132. Post-Cutting Management:
Generally, the time required for propagation by cuttings is about 1-2 weeks for herbaceous plants, about one month for woody and foliage plants (softwood cuttings), and often longer for hardwood cuttings and conifers. Before the cuttings are fully developed, it is necessary to maintain good environmental conditions in the cutting bed, including humidity control, sunlight control, and pest and disease control.
133. Division:
Division is a vegetative propagation method that separates individuals with roots, stems, leaves, or buds from the mother plant. Because the propagated organisms already have the organs needed for self-sufficiency, it is the simplest and easiest method to ensure success among all plant propagation techniques. However, its disadvantage is that the number of individuals divided from the mother plant at one time is limited, resulting in a low propagation rate.
134. Applications of Division:
Division is mostly used for the propagation of perennial herbaceous plants, bulbous flowers, and some flowering trees, foliage plants, and orchids.
The key to successful division
lies in timing, which is arguably the most important factor affecting its success. Depending on the purpose of propagation or renewal, the appropriate time for division varies. If the purpose is propagation, the division should be carried out during the growing season, usually in the same season as the plant. For example, deciduous flowering plants are best divided in early spring, while evergreen flowering plants are best divided from spring to the plum rain season. Plants that bloom from summer to autumn are best divided in spring, while those that bloom from spring to early summer are best divided in autumn, immediately after flowering. For general greenhouse cultivation or indoor foliage plants, division is best done in spring when growth is about to be vigorous. Another factor to consider in determining whether it is the appropriate time for division is the plant's cold and heat tolerance.
136. Division of garden shrubs: Branches
can be separated at the ground level or in the soil, but each separated plant must have a root system at its base. When dividing to propagate a small number of plants or for renewal purposes, it is safer to divide the mother plant into two or three plants. For division, the plant can be dug up with its roots, the soil clump washed away, and then cut apart with scissors or a sharp knife. Alternatively, the dug-up root clump can be directly transplanted elsewhere.
137. Division of perennial grasses
: The plant is dug up, divided, and the new divisions are replanted.
138. Division of bulbous plants:
Bulbous plants can be broadly classified into bulbs, corms, tubers, rhizomes, and rootstocks. The basic structural unit of division must possess both a stem or bud and roots; propagation cannot be done using roots or scales.
139. Division of Foliage Plants:
Many clump-forming foliage plants have underground stems and are often propagated by division. The optimal time for division is between March and September, as long as the temperature is above 15 degrees Celsius. After division, the plant should be placed in a partially shaded, sheltered location. After about a month, once roots have developed, it can be managed as usual.
140. Layering Propagation:
Layering involves injuring the stem or branches of a plant or performing other root-promoting treatments. Roots develop on the mother plant first, then the layered stem is cut off to become an independent new plant. Its main function is for plants that are difficult to root from cuttings, for noble varieties where successful propagation is essential, and for obtaining large, well-developed seedlings.
141. Factors Affecting Root Development :
The robustness of the stem and branches and the health of the mother plant. The technique of cutting. The cleanliness and sterility of the wound. During the rooting period, the layered area should be provided with sufficient humidity and appropriate temperature. To maintain humidity, a clean medium such as sphagnum moss or sawdust is usually used, or a ring is wrapped around the wound. The humidity should be such that water cannot be squeezed out easily, and the area should be covered with a waterproof material to keep the humidity constant. The temperature should be controlled at around 20 degrees Celsius. Too low a temperature will inhibit root development, while too high a temperature can easily lead to dryness or scorching. Rooting promoters are used. Usually, a small amount of rooting promoter is applied to the wound to help promote early root development.