Detailed Guide to Hydroponic Cultivation and Care of Azaleas
How to Grow and Care for Azaleas Hydroponically？
Azalea, also known as yingshanhong, manshanhong, zhaoshanhong, yeshanhong, yingchunhua, and zhizhu. It belongs to the genus Rhododendron in the family Ericaceae. The genus Rhododendron has many species and is widely cultivated in China.
Azaleas (pictured) bloom in profusion, covering branches and bursting across hillsides in a brilliant display, presenting a magnificent scene of "rivers and mountains all in red." Azaleas are evergreen or deciduous shrubs. Plants can reach 2-3 rn in height. They are heavily branched, with hairy twigs. Leaves are alternate, often clustered at branch tips, nearly oblong, with bluntly pointed tips and entire margins. The leaf surface is dark green with sparse hairs; the underside is pale green. Leaves are nearly papery. Flowers are solitary or several clustered at branch tips. The corolla is cup-shaped or funnel-shaped, single or double, with diverse colors. The flowering period is January to May (in South China). The fruit is a capsule.
1. Hydroponic Method
(1) For azaleas, choose a glass container with a planting cup. Remove the soil-cultured plant from its pot, remove the soil, wash the roots clean, trim the fibrous roots, then secure it with the planting cup in a container filled with clean water. Add a small amount of carbendazim aqueous solution for anti-rot disinfection to induce water root growth. Fix the upper part with ceramsite or gravel.
(2) After water roots grow out, appropriately add diluted nutrient solution, submerging 1/4 - 1/3 of the roots. Depending on water evaporation, add clean water once every 3-4 days in summer and once every 10-15 days in winter, and replace the nutrient solution once every 15-25 days. The pH value is 5.5.
2. Care Guide
(1) Light and Temperature During the hot summer, hydroponic azaleas need sun protection and shade; in cold winter, attention should be paid to keeping warm and preventing cold damage. Avoid direct scorching sunlight, as strong light will burn tender leaves; it is suitable to grow under scattered light of low intensity. In winter, place it in a greenhouse to overwinter, with an optimal temperature of 10-15°C. When the temperature drops below 0°C, frost damage is likely to occur; in summer, provide shade, strengthen ventilation, and take cooling measures.
(2) Fertilizing During the bud stage and leaf bud germination stage, azaleas need sufficient fertilizer, requiring a full-strength nutrient solution about every 10d. After the buds break open, foliar fertilizer should be sprayed once every 15 days.
(3) Pruning Old azalea plants should undergo rejuvenation pruning. Before new buds sprout in early spring, leave branches at about 30cm and cut off the upper parts. However, note: do not cut all at once; prune in stages, each time selecting 1/5 - 1/3 of branches for short pruning, completing over 3-5 years. After pruning is completed, fertilization and meticulous management are still needed. Pay attention to routine management to avoid leggy branches, which can maintain vigorous plant growth for a longer period.