A Detailed Guide to Soilless Cultivation Techniques and Growing Methods for Azaleas
Azaleas are mostly grown in pots, which makes soilless cultivation easy to carry out, and the very popular precious Western azalea varieties are especially suited to pot culture. The key points of soilless cultivation for Western azaleas are introduced below.
Growing Methods
Azaleas can be propagated by cuttings, grafting, layering and seed sowing, with cuttings and grafting being the more commonly used methods, as they can preserve the excellent characteristics of the variety. The seed sowing method is mainly used for cross-breeding and selecting superior individual plants.
For cuttings, semi-lignified branches are mostly used, and this can be done from May to August. River sand, perlite plus peat are often used as the substrate. After inserting the cuttings, cover the pot with a plastic bag and place it in a semi-shaded spot. Within 1 week, spray water once each morning and evening, and thereafter keep the potting soil moist. At
a temperature of 20-25°C, most varieties will root in about 40 to 60 days. If the cuttings are treated with rooting powder or vitamin B12, rooting can be faster and more plentiful. If propagating large numbers of cuttings, the full-light mist propagation method can be used, which has the advantages of fast rooting and a high survival rate.
For grafting, Rhododendron pulchrum, which roots easily from cuttings, is usually chosen as the rootstock, and a superior azalea variety is used as the scion, using side grafting, cleft grafting or approach grafting. Varieties that are difficult to root by cuttings or grafting can only be propagated by the high-branch layering method, and generally root in about half a year.
Cultivation and Management
Azaleas are mostly grown in pots, which makes soilless cultivation easy to carry out, and the very popular precious Western azalea varieties are especially suited to pot culture. The key points of soilless cultivation for Western azaleas are introduced below.
Soilless cultivation of Western azaleas usually uses an ordinary medium-sized plastic flower pot (15-20 cm) or a large antique-style ceramic flower pot, depending on the size of the plant. For the growing substrate, acidic materials such as pine needles, peat, sawdust and coconut husk fiber can be used, or a mixed substrate of peat with vermiculite or perlite (2:1). Because azalea roots are fine and slender, large-particle substrates (such as expanded clay pellets) have a smaller contact area with the roots and strong aeration, so they dry out easily; therefore, expanded clay pellets, perlite and the like cannot be used alone.
The nutrient solution for cultivating Western azaleas must be strongly acidic (pH 4.5-5.5), meeting the most suitable environmental acidity requirement for azalea roots. The various nutrients in the nutrient solution should be comprehensive and properly proportioned to meet the needs of azalea growth and flowering. A special azalea nutrient solution or a general nutrient solution can be used.
After planting, the first application of nutrient solution (diluted 3-5 times) should be thorough. Place in a semi-shaded spot for about half a month to let the plant recover, then enter normal management. For regular feeding, apply once every 10 days, 100-150 ml each time for a medium pot; 200-250 ml for a large pot. For regular watering, keep the substrate moist, but never allow water to accumulate in the pot or in the saucer under the pot. Azaleas cannot tolerate alkalinity; usually the tap water in cities has a pH above 7, and watering with this water over the long term will cause the leaves to turn yellow, drop off and even die. A simple solution is to set up a water vat where the azaleas are planted, to sun the water, and you can put some green grass, vegetable leaves, melon and fruit peels, etc. in the water; after about a week, the pH of the water can drop below 7. If you want it clean and clear, you can use vinegar essence or edible vinegar to adjust the acidity and alkalinity of the water, about 1 tablespoon of edible vinegar to 500 ml of water. It is best to prepare some pH test strips yourself, test the pH of the water before watering, and if it is too alkaline, adjust it to a suitable level before watering.
Throughout the entire growth process, potted azaleas need a semi-shaded environment. In spring, summer and autumn, shading is needed, and indoors at home strong direct sunlight should also be avoided; in winter, some sunlight can be allowed. High-temperature, stuffy summer weather often causes azalea leaves to yellow and drop, and even death, so attention should be paid to ventilation and cooling, and misting to lower the temperature. In winter, a room temperature of around 10°C is suitable.
By using the above soilless cultivation method, it is believed that azaleas can be grown well in areas with either acidic or alkaline water quality.
Soilless Cultivation Techniques for Azaleas
Soilless Cultivation Techniques for Azaleas(I) Biological Characteristics
It is one of the top ten famous flowers, with great ornamental value. It forms different morphological characteristics in different natural environments; there are evergreen trees, small trees and shrubs, as well as deciduous shrubs, and its basic form is an evergreen or deciduous shrub. It has many branches, alternate leaves, and a dark green surface. It has raceme inflorescences, with flowers terminal, axillary or solitary, and the flower colors are rich and varied; some species have numerous varieties.
Azaleas are widely distributed, throughout the cold and temperate zones of the Northern Hemisphere. There are more than 900 species of azaleas in the world, and China has more than 650 species. Their vertical distribution can range from flat ground up to an altitude of 5
(II) Growing Methods
1. Cutting method The best time for cuttings is during the plum rain season, when the temperature is moderate and the survival rate is high. For cuttings, choose new branches of the current year that have already become lignified and fairly firm. Each cutting is about 7-
2. Layering method The advantage of this method is that the resulting plant is larger. The method is to bend a branch at the base of the mother plant down and press it into the substrate in a pot; after 5-6 months, once it has rooted, sever it and pot it up. If the branch is at the upper end and cannot be bent down, then use the air layering method, that is, use a bamboo tube or plastic film filled with soil to retain moisture (the same as for propagating roses, osmanthus, etc.). Take care to water frequently; after seven or eight months new roots will grow.
3. Grafting method Some azalea varieties, such as 'Wang Guan', 'Gui Xiao', 'He Zhi Zhu', etc., do not propagate well by cuttings, and can be propagated by grafting. For the rootstock, choose a robust, second-year Rhododendron pulchrum with strong vitality and good cold resistance, while the scion mostly uses Western azaleas with brilliant flower colors and better flower shapes.
There are three grafting methods: approach grafting, bud grafting and side grafting.
(1) Approach grafting Select one pot each of rootstock and scion azaleas, place them side by side close together, choose a smooth, node-free area where the growth is full and the branch thickness (rootstock and scion) is basically the same, and make one cut on each, with the cut surface about 3-
(2) Cleft grafting Choose a two-year-old Rhododendron pulchrum as the rootstock, cut off the top bud and trim it flat. Then make a cut in the very center, to a depth of
(3) Side grafting Take a scion 4—5 cm long, keep 3—4 leaves at the top, remove all the lower leaves, and cut both sides of the stem into a wedge shape with a sharp knife, 0.5—
(III) Soilless Cultivation Techniques
1. Variety selection Varieties suitable for soilless cultivation include:
(1) Western azalea Flowers and leaves appear together, leaves thick and glossy, flowers large and brilliant, many double-petaled, flowering period May-June.
(2) Summer azalea Leaves appear first and then flowers, leaves relatively small, branches and leaves dense, leaf shape narrow and pointed, densely covered with fine
hairs. Flowers are single-petaled and double-layered, flowers relatively small, flowering period June.
(3) Yingshanhong Flowers appear first, then branches and leaves grow; cold-resistant, often with 3 flowers clustered at the tip of the branch, 5 petals, bright red, flowering period February-April.
(4) Wang Guan Semi-double, white ground with red edges, with green spots at the base of the upper 3 petals, very beautiful, hailed as the king of azaleas.
(5) Ma Yin Hua Evergreen in all four seasons, flowers red or purple-white, with spots on the flowers. Flowers in May-June.
2. Preparation of soilless cultivation substrate For azalea cultivation, a mixed substrate is best, and there are several substrate formulas to choose from.
① 4 parts leaf mold, 3 parts humic acid fertilizer, 2 parts black mountain soil, 1 part superphosphate.
② 3 parts peat, 2 parts sawdust, 3 parts leaf mold, 1 part sugarcane bagasse, 1 part superphosphate.
③ 5 parts accumulated dead leaves, 2 parts vermiculite, 1 part sawdust, 1 part superphosphate.
④ 4 parts lichen, 2 parts gravel, 2 parts plastic foam granules, 2 parts mountain yellow soil.
The formula substrate must be mixed evenly, disinfected, and then put into pots for later use.
(1) Potting Potting is best done in autumn before or after moving into the greenhouse, or in spring when moving out of the greenhouse. The potting method is: cover the drainage hole crosswise with a few broken pot pieces or tiles, first put a thin layer of granular gravel on the bottom layer, then add cinders, then add coarse soil particles, and put a layer of fine soil on the topmost layer. Place the seedling in the center, with the roots fully spread out and at an appropriate depth. Then hold the seedling with one hand, and with the other hand add the evenly mixed substrate into the pot up to the root crown, firm the substrate in the pot, then add an appropriate amount of substrate until it is 2-
(2) Repotting After potting, the plant grows vigorously and becomes a large seedling with dense branches and leaves and a well-developed root system, and should be moved to a larger pot. Otherwise, because the roots cannot spread out in a small pot and become tangled together, they can neither fully absorb fertilizer and water nor allow proper aeration and drainage. The plant's growth will then decline; at the same time, after a period, the substrate deteriorates and also needs to be replaced with new substrate. Whether repotting is needed is judged mainly by the plant's vigor; as long as the tree's vigor does not show serious decline, it does not need repotting. Usually repotting once every 3 years or so is best. Large plants tend to have correspondingly larger pots, and can also be repotted once every 5 years or so. Extra-large ones, as long as their vigor does not decline, can also go many years without repotting.
When repotting, use a stick or flat knife to cut along the inner edge of the pot, so that the roots attached to the inner rim of the pot are peeled away, then lift the plant so that it comes out of the pot, remove the broken pot pieces or tiles stuck to the bottom of the root ball, loosen the substrate around the roots, peel off some of the old soil at the edges so that the surrounding roots spread out, but the substrate at the top center does not need to be broken up. Cut off overly long roots and blackened diseased roots and old roots, to encourage new roots. The operation of repotting into a new pot is the same as for potting, and the season for repotting is similar to that for potting, but plants that have already entered full bloom should preferably be repotted after flowering.
(3) Watering Azalea roots are fine and weak, and can tolerate neither drought nor waterlogging. If water is not supplied in time during the growing period, the roots will shrink, the leaves will droop or curl, and the tips will turn scorched yellow; in severe cases they cannot recover for a long time and gradually die. If watered too much, aeration is blocked, which causes root rot; in mild cases the leaves yellow and drop and growth stops, and in severe cases the plant dies. Therefore, watering azaleas cannot be neglected; when the climate is dry, water thoroughly, and during normal growth, water appropriately only when the surface of the potting soil is dry. If growth is poor, with leaves grayish-green or yellow-green, you can add or use alone 1/1 000 ferrous sulfate solution to water 2-3 times when fertilizing.
When watering azaleas, attention should be paid to water quality. Clean water sources must be used, and when watering, the water temperature should preferably be close to the air temperature. Tap water in cities contains bleaching powder, which is harmful to plants, and must be stored for several days before use. Water containing alkali should not be used. Water quality in the north tends to be alkaline, so sulfuric acid can be added to adjust the pH before use.
(4) Nutrient solution management The azalea nutrient solution is required to be strongly acidic, with pH 4.5-5.5 being suitable. The various components of the nutrient solution are required to be comprehensive and properly proportioned to meet the needs of azalea growth and flowering. A special azalea nutrient solution or a general nutrient solution can be used. After planting, the first nutrient solution (diluted 3-5 times) should be thorough. Place in a semi-shaded spot for about half a month to let the plant recover, then enter normal management. Normally, feed once every 10 d, 100-
During the soilless cultivation of azaleas, a semi-shaded environment is always required. In spring, summer and autumn, shading is needed. High-temperature, stuffy summer weather often causes azalea leaves to yellow and drop, and even death, so attention should be paid to ventilation and cooling or misting to lower the temperature. In winter, the room temperature should be
Which flowers are suitable for soilless cultivation? What are the key care points for soilless cultivation of flowers?
The soilless cultivation environment is an artificially created crop growing environment, which can then replace the soil environment. It can make plants grow rapidly and robustly, bloom more and earlier, larger and more fragrant, and be resistant to cold and heat, with fewer pests and diseases.
Today we will take you through an introduction to which flowers are suitable for soilless cultivation, and what the key care points are.
Which flowers are suitable for soilless cultivation?
Monstera deliciosa, Aglaia odorata, Clivia miniata, camellia, Chinese rose, jasmine, azalea, kumquat, Rohdea japonica, violet, Phalaenopsis, fuchsia, five-needle pine, banana shrub, rubber fig, Brazilian iron, begonias, ferns, palms, etc. Potted flowers can be converted from soil cultivation to soilless cultivation in any season.
Key Care Points for Soilless Cultivation of Flowers 1. Preparing the nutrient solution:
Dilute the soilless cultivation nutrient solution sold on the market with water according to the specified multiple. You can also prepare the nutrient solution yourself using the following formula.
1、Macronutrients: potassium nitrate and magnesium sulfate 3 g each, calcium nitrate 5 g, ammonium phosphate 2 g, potassium sulfate and potassium dihydrogen phosphate 1 g each;
2、Micronutrients: (using chemical reagents) disodium edetate 0.1 g, ferrous sulfate 75 mg, boric acid 30 mg, manganese sulfate 20 mg, zinc sulfate 5 mg, copper sulfate 1 mg, ammonium molybdate 2 mg;
3、5 kg of tap water. Prepare the macronutrients and micronutrients into solutions separately, then mix them together to make the nutrient solution. The amount of micronutrients used is very small and not easy to weigh, so you can prepare them at an enlarged multiple, and then extract the amount by reducing at the same multiple. For example, you can weigh out the micronutrients enlarged 100 times to prepare a solution, then extract 1% of that solution, which is the required amount. The nutrient solution is non-toxic, odorless, clean and hygienic, and can be stored for a long time.
2. Removing from the pot:
Use your fingers to push the root system together with the soil out from the hole at the bottom of the pot.
3. Washing the roots:
Soak the soil-covered root system in water close to the ambient temperature, and wash the soil off around the roots.
4. Soaking in liquid:Soak the washed roots in the prepared nutrient solution for 10 minutes, allowing them to fully absorb nutrients.
5. Potting and pouring in liquid:
Wash the flower pot clean, place tiles or plastic gauze over the hole at the bottom of the pot, then put a little perlite and vermiculite in the pot, then place the plant in the pot and hold it upright, and fill perlite, vermiculite and other lightweight ore around the roots. Shake the pot gently so that the ore and roots are in close contact. Then pour in the prepared nutrient solution until liquid flows out from the hole at the bottom of the pot.
6. Reinforcing the root system:
Place fragments of fluorite, ax-split stone, etc. on top of the root system to reinforce it and prevent lodging. At the same time, spray some clean water on the leaves.
7. Daily management:
For soilless-cultivated flower bonsai, the requirements for light, temperature and other conditions are no different from soil cultivation; during the plant's growing period, apply nutrient solution once a week, with the amount depending on the size of the plant, and reduce the amount as appropriate for flowers whose leaves grow slowly; in winter or during the dormant period, apply once every 15-30 days. Indoor foliage plants can survive under low-light conditions, so the amount of nutrient solution should be reduced, and the nutrient solution can also be used for foliar spraying. At ordinary times, pay attention to watering at the right time.
The above is all the content I have learned today about which flowers are suitable for soilless cultivation and the key management and care points. I hope that after reading this article, it will be helpful to all flower lovers. To learn more about cultivation techniques, please continue to follow our Succulent Garden, and we will provide you with more related knowledge!