How to grow flowers and green plants hydroponically? A full breakdown of methods and tips

Hydroponic flowers use water as the medium, growing flowers directly in a water-filled container and supplying the nutrients they need for growth, making them a type of flower used for indoor greenery decoration.

I. Advantages of hydroponic flowers

Hydroponic flowers are clean and hygienic, with few pests and diseases, and are good for human health; they have an elegant style and strong ornamental value. Hydroponically grown flowers let you enjoy the leaves, stems and flowers, and also admire the ever-changing root system, which increases their decorative appeal; they free you from the trouble of finding soil and managing various soil mixes for potted plants, suiting the high-efficiency, fast-paced characteristics of modern society. You can use the endlessly varied forms and colors of flowers and arrange and lay out several kinds of flowers at will, achieving an artistic effect similar to flower arranging.

II. Flower species suitable for hydroponics

Flower species suitable for hydroponics include, among herbaceous flowers, Cymbidium sinense, Oncidium, spider plant, umbrella plant, Tradescantia pallida, Tradescantia spathacea, Lophatherum gracile, Tradescantia zebrina, and lucky bamboo; among woody flowers, jasmine, money tree, Brazil wood, weeping fig, osmanthus, kumquat, Chinese rose, Schefflera octophylla, croton, Rhapis excelsa, ivy, and dragon blood tree; among foliage plants, asparagus fern, lucky bamboo, Monstera deliciosa, snake plant, red ruby, Caladium bicolor, giant green, pothos, Golden Queen, Silver Queen, golden-striped lucky bamboo, Philodendron 'Green Emerald', Syngonium podophyllum, large-leaf Dieffenbachia, Dieffenbachia seguine, spotted Dieffenbachia, and more; among bulbous flowers, tulip, hyacinth, cyclamen, Chinese narcissus, calla lily, tuberose, and lily; and among succulent-stemmed flowers, Christmas cactus, crown of thorns, cactus, and jade plant.

III. Planting techniques

Generally, special hydroponic pots with no bottom holes and double inner and outer mesh nesting pots are used; for ordinary households, containers with a certain degree of transparency are all suitable. Schedule planting from mid-April to mid-to-late June, and from late September to early November. During this period the temperature is suitable and the plants' vital activities are vigorous, so both planting and water cuttings root easily.

Select potted flowers with a good plant shape and strong growth, and rinse the soil or other medium off the roots with water. Plants with weak growth have few nutrients in their bodies and relatively slow physiological activity, so washing the roots and growing them hydroponically will affect their root development and growth, and they are therefore not suitable for selection. For some flower species suitable for hydroponics, you can also cut fully developed semi-mature branches during their vegetative growth period and insert them in water to let them root. For succulent and multi-pulp plants, whose stems have soft water-storing tissue, the branches should not be inserted directly into water after being cut from the mother plant; instead, place the cuttings in a cool, dry place for 2-3 days, and only carry out water cuttings after the wound is fully dry.

When planting, for those with very dense roots, 1/3-1/2 of the fibrous roots can be trimmed away. Root trimming helps the root system of hydroponically grown plants regenerate, sprout new roots earlier, and thereby promotes the plant's absorption of nutrients. After trimming, first soak the roots of the plant or the base of the cuttings in a 5 g/L potassium permanganate solution for half an hour, then insert the roots separately into the mesh holes, spreading the roots out as much as possible, and operate carefully so as not to damage the roots again, then use vermiculite or ceramsite, sponge, etc. to press the plant firmly in place.

IV. Post-planting care

Whether using double nesting pots or single-layer pots, the water should be changed regularly, and this is the key to successful hydroponic flowers. This is because when the flower's roots grow in water, they produce mucus, and too much mucus will pollute the water quality. In hydroponic flowers, apart from the portion of mineral elements in the nutrient solution absorbed by the flowers, the rest remains in the water. When the residual substances accumulate to a certain level, they will harm the flowers' growth. The oxygen content in the water will gradually decrease as the flowers grow, and when it drops to a certain amount, it will affect the flowers' growth.

For ordinary flowers growing normally, change the water once every 7-10 days in summer, about every 15 days in spring and autumn, and every 15-20 days in winter. When changing the water, wash away the mucus on the roots and cut off rotten roots and yellow leaves. For hydroponic flowers that have just been repotted, because there are many new wounds on the roots and they rot easily, the water must be changed frequently; especially in high-temperature weather, when the oxygen content in the water decreases and the plant's respiration strengthens and consumes more oxygen, the water must be changed even more frequently, every day, until the flowers grow white new roots in the water, after which the frequency of water changes can be gradually reduced.

Before changing the water, first pour out the accumulated water in the outer pot, then repeatedly rinse the inner pot's medium or the single-layer pot with clean water to wash away the remaining nutrient solution; at the same time, rinse the plant's root system with water. Then, water thoroughly with fresh nutrient solution. Normally, after 20%-30% of the water is consumed, it must be replenished with water; be careful not to fill the water too full, and let part of the root system be exposed above the water.

Under hydroponic conditions, however, all the fertilizer applied dissolves in the water, and as long as its concentration slightly exceeds the level the flowers can tolerate, fertilizer damage will occur. Therefore, hydroponically grown flowers should generally be given a measured amount of special nutrient solution. The nutrient solution is formulated according to the proportion, concentration and pH of the nutrients the flowers need.

The suitable growth temperature for indoor hydroponic flowers is 18°C-25°C. If constantly kept in a high-temperature nutrient solution, the roots of hydroponic flowers will turn dark brown; in severe cases they will also rot, which can cause the whole plant to die. Therefore, in summer, prevent direct sunlight on the water pot, so as not to make the water inside the pot scalding hot and damage the plant's roots. When the flowers overwinter, avoid cold air invasion to prevent freezing damage. You can take measures such as sprinkling hot water on the ground and turning on a hot-air blower for heating.