How to grow azaleas with soilless culture? Master these key technical points

1. Preparation of the substrate. Azalea roots are very fine and require a loose substrate to facilitate aeration and drainage. Mix 1 part vermiculite, 1 part perlite sand, 1 part river sand, and 1 part coal cinder in proportion. After mixing the substrate, sterilize it with a 0.1% carbendazim solution, stir it evenly into the substrate, and cover with plastic film for 1 day. Then rinse it multiple times with clean water, and after air-drying, mix it evenly with a 0.4% agricultural compound fertilizer solution, then cover with plastic film for one month, after which it can be used for potting.

2. Preparation of the nutrient solution. Azaleas have relatively strict fertilizer requirements. During the growing period, apply light fertilizer frequently. According to experiments, using agricultural compound fertilizer as the main component, supplemented with trace elements, controlling the pH value at around 5, and spraying a low-concentration foliar fertilizer can achieve good results. Preparation of major elements: add 2 grams of agricultural compound fertilizer to 1 liter of water, then add 0.5 grams of magnesium sulfate; this is the standard solution. Preparation of trace elements: add 20 grams of disodium edetate, 15 grams of ferrous sulfate, 4 grams of manganese sulfate, 6 grams of boric acid, 0.2 grams of zinc sulfate, 0.1 grams of copper sulfate, and 0.2 grams of ammonium molybdate to 1 liter of water as the mother solution. When using, add 1 milliliter of the trace element mother solution to 1 liter of the standard solution to obtain the full-strength element solution. Preparation of foliar fertilizer: add 1 gram of urea, 1 gram of monopotassium phosphate, 0.02 grams of boric acid, and 0.1 grams of vitamin B1 to 1 liter of water.

3. Water and fertilizer management. Because the substrate has good drainage and aeration but poor water retention, the amount of watering is generally a bit more than with soil culture, just enough to keep the substrate moist. When buds are forming and leaf buds are sprouting, the fertilizer requirement is relatively high; water with full-strength nutrient solution about once every 10 days. From March until the flower buds open, spray foliar fertilizer about once every 15 days. After flowering, the water requirement is high; in addition to watering every day, spray water on the leaves in the evening. At this time, the fertilizer requirement is also high, so it can be changed to watering with nutrient solution once a week and spraying foliar fertilizer once, to promote sturdy new branches and facilitate flower bud differentiation. After the dog days begin, pay attention to keeping the substrate moist and spray water on the leaves; the fertilization amount can be reduced to watering with nutrient solution about once every 20 days. After the autumn cools, the amount of fertilizer used can be gradually increased; apply full-strength nutrient solution about once every half month and spray foliar fertilizer 1 to 2 times to promote healthy and robust growth of flower buds. After winter begins, the physiological activity of azaleas is weak, so fertilization is not suitable; simply water appropriately according to the degree of dryness or moisture of the substrate.