1. What are hydroponic flowers?

Hydroponic flowers, popular in the market, are a type of soilless flower cultivation, belonging to nutrient solution culture. This means growing flowers away from soil , in an environment with different physical and chemical properties than soil , using specialized nutrient solutions . Examples include hydroponics using pure water or gravel hydroponics using substrates like expanded clay pebbles or colored sand . This method offers low growing costs , allows for multi-layered planting , and even allows for the co-cultivation of flowers and fish . The flowers display red flowers and green leaves on top , while the roots sway below , and fish swim freely in the water . Without soil or traditional fertilizers , it prevents the growth of viruses, bacteria, insects , and unpleasant odors . Placing hydroponic flowers indoors not only increases humidity but also allows the leaves to absorb carbon dioxide , release oxygen , and provide fragrance , offering benefits such as improved eyesight, liver health, lung cleansing, and overall well-being.

2. How to convert soil-grown flowers to hydroponic flowers

2.1 Selection of Containers and Utensils

Hydroponic plants showcase the beauty of their root systems, so the containers should be clear and transparent. The market now offers a wide variety of transparent glass, plastic, and acrylic vases in diverse shapes and sizes. Compared to soil-grown pots, these vases are more elegant, better complement the home environment, and enhance the decorative effect and overall taste.

You can buy your favorite hydroponic flower containers at flower shops, or you can make your own by modifying some of the utensils you already have at home, such as buckets, basins, cups, beverage bottles, mineral water bottles, etc. This not only reuses waste, but also fully utilizes your imagination for artistic creation, and the fun is no less than growing flowers itself.

In addition to containers, hydroponic plants also require nutrient solution, scissors, a watering can, work gloves, and other tools.

2.2 Root washing treatment for hydroponic plants

For flowers grown in soil , first moisten the soil with water , then remove the plant , remove the soil , and wash the roots with clean water before use.

Plant selection: First, plants intended for hydroponics should have an attractive shape and good decorative effect. Small plants are not aesthetically pleasing and are unsuitable for root washing. Second, the plants should be healthy and free from pests and diseases. Healthy plants recover easily and adapt well to aquatic environments. Newly divided plants with weak root systems are also unsuitable for root washing; they can be grown in a solid substrate until their root systems are more developed before root washing.

Key points for root washing techniques: First, avoid excessive damage to the root system during washing to prevent rot. Second, prune appropriately; old and rotten roots should be trimmed. For some plants with very extensive root systems, prune 1/3 to 1/2 . Pruning reduces oxygen consumption and promotes the development of new aquatic roots. Some plants with sparse root systems do not require pruning, which is beneficial for their adaptation to the aquatic environment; only the lower branches and leaves should be lightly pruned. Third, disinfect to prevent wound infection. Use a fungicide such as 800 times diluted carbendazim or 600 times diluted chlorothalonil. Fourth, when planting, the roots should be spread out and not crammed into the nutrient solution, as this easily leads to root rot and hinders plant recovery.

The best time to wash roots: Root washing is more successful in warm seasons. Low temperatures weaken plant growth and hinder root development, while high temperatures reduce oxygen levels in the water, easily leading to root rot. Therefore, a temperature of around 20 °C is suitable, with late spring, late summer, and early autumn being the most appropriate times.

2.3 Water level control

Place the washed plant in a water bottle , allowing the roots to spread out, and add clean water and nutrient solution . The water level should be low, not high. The roots only need to be submerged in water , or even less . Allow the plant to acclimate for about a month , changing the water approximately every four days to keep it clean and add nutrient solution .

2.4 Use of nutrient solution

When hydroponically growing at home , the static hydroponics method is basically used , which results in a low nutrient content in the water . Therefore , it is necessary to supplement nutrients appropriately.

For the nutrients needed by hydroponic flowers , it is recommended to use commercially available nutrient solutions . Different plants require different nutrients , therefore the formulas of nutrient solutions also vary . When purchasing, you can choose different nutrient solutions according to the type of plant you are cultivating. Flower shops generally offer a variety of nutrient solutions for customers to choose from , such as complete nutrient solutions, hydroponic acclimatization solutions, foliar fertilizers, rooting nutrient solutions, seed soaking nutrient solutions, foliage plant nutrient solutions, clivia nutrient solutions, cactus nutrient solutions, etc. Regardless of the type of nutrient solution , it is essential to strictly follow the instructions for dilution before use , adhering to the principle of "less is more" to avoid over-application and fertilizer burn. When storing nutrient solutions , they should be placed in a dark, cool place to prevent chemical changes and deterioration caused by strong light and excessively high temperatures.

2.5 Pre-construction maintenance

In the initial stages of root washing and hydroponics, the plant should be placed in a cool, shaded area without strong sunlight to facilitate recovery. After being washed from the soil substrate and introduced into the water environment, the plant undergoes an adaptation and recovery process. During this time, wilting and yellowing leaves may occur. Strong sunlight will exacerbate these phenomena , affecting recovery and the plant's ornamental value. Once new roots have grown, the plant will gradually regain its upright posture and vitality.

Once the plant develops new roots, it can be managed normally , generally requiring water changes every two weeks . Most plants undergo a process of adapting their terrestrial roots to aquatic environments. Species that adapt easily quickly develop aquatic roots from their old roots , such as anthuriums, peace lilies, clivias, and lucky bamboo. Some plants, like cordyceps and dracaena, must develop new aquatic roots to adapt to aquatic conditions. Some species may experience root rot ; in this case, in addition to frequent water changes, it's necessary to trim the substrate roots , clean the container, and rinse the plant's roots until new aquatic roots grow .

3. Daily Management of Hydroponic Flowers

3.1 Nutritional Supply

Use fertilizers specifically formulated for hydroponics whenever possible , and strictly follow the instructions for use to prevent fertilizer burn from over-application or excessive concentration. Generally, add nutrient solution after each water change to replenish nutrients lost during the process.

Other points to note include:

Appropriate nutrient application based on different flower species: This is because different flower species have different nutritional tolerances. Generally, flower species with delicate root systems, such as coleus and begonias, are less tolerant of fertilizer and do not require large amounts or high concentrations of fertilizer. Therefore, when supplying them with nutrients, the principle of "dilute, less, and diluted" should be followed. Many other flowers, such as syngonium, philodendron, and philodendron, are more tolerant of fertilizer and can be fertilized sparingly and frequently. Additionally, for foliage plants, the primary nutrient should be nitrogen, supplemented with phosphorus and potassium to ensure thick, smooth leaves with pure color. However, it is important to note that for flower species with colored stripes or patches on their leaves, nitrogen should be applied less, as excessive nitrogen can cause the leaf color to fade or even disappear . Appropriate increases in phosphorus and potassium fertilizers should be applied instead.

Add nutrients appropriately according to the season and temperature: Generally, during the high temperatures of summer, flowers' tolerance to nutrient solution concentration decreases, so the concentration applied should be reduced at this time. This is especially important for flowers that are sensitive to heat; during the hot season, they enter a dormant state, their physiological activities slow down, and their growth is semi-stopped or ceased. For these flowers, adding nutrient solution should be stopped at this time to avoid fertilizer burn.

3.2 Change the water and wash the roots

Generally, water changes should be done every 5-7 days. However, this depends on the season and the specific plant. Newly hydroponically grown plants require water changes every 1-2 days. In summer, when plant growth is vigorous and temperatures are high, the water is prone to spoilage, so the interval should be shortened. In winter, most plants are in a semi-dormant or dormant state, and temperatures are lower, so the interval between water changes can be longer. Overall, shorter intervals between water changes are beneficial for plant growth.

When hydroponically growing flowers, the roots should not be completely submerged in water. When adding water to the container, do not add too much; leave a small portion of the roots exposed to the air so that they can absorb dissolved oxygen from the water and oxygen from the air.

When changing the water, the root system should be cleaned. Rinse off the mucus on the roots with clean water and trim away any rotten roots and old roots that have lost their ability to absorb nutrients . After the container has been used for a period of time , some sediment will stick to the walls , and it is also prone to growing moss . It should also be cleaned when changing the water .

3.3 Spray water to wash leaves

Hydroponic flowers, especially indoor hydroponic foliage plants , mostly prefer high humidity . If the indoor air is too dry , the tips or edges of the leaves will scorch , thus affecting the ornamental value of the flowers. Therefore , it is advisable to frequently spray water on the plants to increase the humidity , which is beneficial to their normal growth.

3.4 Proper ventilation

The success of hydroponic plants is directly related to the oxygen content in the water , which in turn is affected by indoor activity and ventilation. When indoor ventilation is poor and people are frequently active , the oxygen content in the water decreases rapidly , negatively impacting the growth of hydroponic plants . Conversely , maintaining good indoor ventilation increases the oxygen content in the water. Therefore , areas where hydroponic plants are grown should have enhanced ventilation to keep the indoor air fresh.

3.5 Lighting and Temperature

Most hydroponic flowers are shade-loving or neutral plants suitable for indoor cultivation , each with its own light requirements. Shade-loving plants , such as ferns, orchids, and Araceae, should be moderately shaded; neutral plants, such as Monstera deliciosa, Schefflera arboricola, and poinsettia, are not demanding in terms of light intensity and generally prefer full sunlight, but can also grow normally in shade. Maintaining the correct temperature for the plants' normal growth is crucial; their root systems thrive best within a range of 15-30 °C.

3.6 Timely pruning

For some hydroponic flowers with vigorous growth and well-developed root systems , when the branches become too long and affect the plant's shape , they should be pruned in a timely manner to avoid affecting their appearance. The pruned branches can be inserted into the container of the flower to take root and grow , making the entire plant fuller and more perfect. The best time to prune the roots is in spring when the flower begins to grow . You can also do this during water changes , trimming away excess, old, and rotten roots as needed to promote normal growth.

3.7 Keep clean

We know that hydroponic plants rely on inorganic nutrients and are highly susceptible to damage from organic matter entering the water, especially organic fertilizers. Therefore, maintaining the cleanliness of hydroponic plants is crucial for their healthy growth. Avoid adding food or organic fertilizers to the water. Also, refrain from putting your hands into the water to ensure it remains clean and uncontaminated, thus guaranteeing the plant's healthy development.

4. Common Diseases and Prevention of Hydroponic Flowers

4.1 What could be the reason why the plant's roots break off naturally and the entire root system becomes soft and rotten but has no foul odor?

This situation is mainly caused by frost damage. When the temperature is below 5 ℃, the plant will suffer frost damage. This is mainly seen in plants of the Araceae family such as Marian, Silver Queen, and Snow White. You can trim the broken part and put it back in the nutrient solution for cultivation, and wait for it to grow new roots.

4.2 Why does the water in the plant placed near the window turn green ?

This is mainly caused by algae growth . As long as you change the water frequently, there shouldn't be any major problems . You can also provide some shade from the sun .

4.3 What should I do if the edges of my plant leaves turn yellow ?

There are approximately four reasons for this situation : ( 1 ) the nutrient solution is not properly prepared and the concentration is too high; ( 2 ) the light is too dim; ( 3 ) the water level is too high; ( 4 ) there are pests and diseases.

Solutions : ( 1 ) First, replace with clean water or grow in a nutrient solution with a very low concentration for 2-3 days , then replace with a nutrient solution that has been reconstituted according to the correct ratio; ( 2 ) Place it next to a window where there is sufficient diffused light to supplement the light . For example, shade-loving plants should be placed next to a window where there is sufficient diffused light every week; ( 3 ) Pour out the excess water and keep the water level at the correct level; ( 4 ) Observe whether there are abnormal spots or other abnormalities on the surface and back of the plant leaves , and then spray the medicine according to the symptoms until the pests and diseases are eliminated ( during this period, pay attention to isolating it from other plants to avoid infection ) .

4.4 Pest and Disease Control

When planting flowers, the operator should wash their hands first . Handling flowers with greasy hands can cause blisters and foul odors at the roots or bacterial mold spots on the leaves . In such cases, a fungicide like chlorothalonil can be sprayed for prevention . Red and white spider mites are prone to infestation during the hot and humid spring and summer months. These mites mainly hatch from eggs already present on the plant in hot, poorly ventilated environments . They appear as small red or white spots on the underside of the leaves , and the leaves lack luster . In such cases, acaricides such as miticides like abamectin can be used for control .

5. Trivia

5.1 Top Performer in Hydroponics

The Araceae family comprises 105 genera and over 2,500 species , originating in tropical Asia . They grew in waterways or swamps in forested areas . Through a long history of evolution , the vast majority of them have now developed into terrestrial plants , with very few aquatic species .

The most primitive genus in the Araceae family is *Acorus* , while the most evolved is *Ipomoea* , both of which are aquatic plants . Common beautiful ornamental plants ( genera ) in the Araceae family include : *Anthurium*, *Swiss Cheese Plant*, *Alocasia*, *Epipremnum*, *Zantedeschia*, *Aglaonema*, *Calathea*, *Philodendron*, *Calathea*, and *Alocasia*. Although all of these plants are terrestrial, they are closely related to aquatic vascular plants: some are inherently wetland species, some have aerial roots, some readily develop adventitious roots, and some readily develop aerenchyma under stress.

Araceae plants evolved from aquatic genetic origins, share a common ancestor with aquatic floaters, and are related to Liliales, Arecales, and other orders containing aquatic species. Their aquatic genetic content makes them top choices for static hydroponics.

5.2 Treatment of root rot

During hydroponics, due to factors such as low temperature, over-concentration of fertilizer, or disease, the roots of hydroponically grown plants may rot. The rotting roots emit a foul odor; at the same time, the water in the container becomes contaminated and also emits a foul odor. After the roots have rotted, the outer skin can be easily torn off by gently pulling on the root collar, leaving only the lignified part.

If root rot occurs , it should be pruned promptly . Root rot usually starts from the root tip and gradually spreads upwards. When pruning, cut until you reach the healthy root system. If the roots turn yellow or discolored , it indicates that they are also damaged and should be pruned immediately . After changing the water , observe carefully . If root rot continues to occur , take immediate action.

5.3 Using a substrate

Hydroponic substrates are materials used to cultivate flowers in place of soil . They function similarly to soil, anchoring plants, retaining water and fertilizer, providing good aeration, and offering some chemical buffering capacity. Many types of hydroponic substrates are available, such as expanded clay pebbles, sand, perlite, and peat moss. Currently, colorful substrates like crystal soil and rainbow sand are quietly emerging in the market. Substrate cultivation is simple and easy, and plants are more likely to survive, hence its widespread use.

5.4 How to increase the dissolved oxygen content of nutrient solution

Replacing the nutrient solution is the simplest way to increase dissolved oxygen. Measurements show that fresh nutrient solution has a 70% to 90% higher dissolved oxygen content than the original solution, which can promptly improve the physiological oxygen deficiency of flowers . If there is an aquarium nearby while cultivating hydroponic flowers , you can use the spare air outlet of the aquarium air pump connected to a rubber tube to aerate the hydroponic container ( the airflow should not be too strong to avoid splashing the nutrient solution ) . Oxygenation through airflow is also quite effective. For hydroponic flowers in smaller containers , as long as the roots are clear and undamaged and the nutrient solution is transparent , you can use the vibration method to increase oxygen . Hold the plant firmly with one hand and the container firmly with the other hand , and gently shake it more than 10 times . The dissolved oxygen content of the nutrient solution after shaking can increase by more than 30% .