What are the precautions for foliar feeding of orchids?

(1) Spraying should be targeted. That is, choose the corresponding fertilizer according to the nutrients the orchid plant needs at each growth stage, and supply it in a targeted way. For example, during the new shoot growth period, nitrogen fertilizer should be the main nutrient, and it only works when combined with potassium fertilizer; when the new shoots mature, potassium fertilizer should be added to ensure the plant grows strong; during the bud gestation period, phosphorus fertilizer should be added; in addition, variegated-leaf orchids should be given less nitrogen fertilizer to prevent excessive nitrogen from increasing chlorophyll and causing the variegation to fade.

(2) Mixing should be scientific. Although commercial foliar fertilizers have relatively complete nutrient content, do not always use the same variety; fertilizers of different varieties should be mixed and used alternately to make up for each other's shortcomings and make the nutrition more comprehensive. For example, when using urea as a foliar fertilizer, it must be mixed with monopotassium phosphate, otherwise the plant tends to grow excessively. In general, it is also necessary to grasp that acids and bases should not be mixed, and biological bacterial fertilizer should not be mixed with other fertilizers.

(3) The concentration ratio should be appropriate. Use the concentration strictly according to the relevant instructions, and it is strictly forbidden to increase the concentration at will, otherwise it will be counterproductive, cause fertilizer damage, and even inhibit orchid growth. Under normal circumstances, liquid fertilizer should be measured with a syringe, and solid fertilizer should be weighed with a balance.

(4) The spraying time should be reasonable. Foliar feeding should not be carried out in the morning. Generally, on a clear evening when sunlight cannot reach the leaves, it is best if they can dry within one hour after spraying. This is good because on the one hand it helps the orchid leaves absorb nutrients at night, and on the other hand it avoids fertilizer damage and reduced effectiveness caused by light, especially preventing liquid accumulation in the leaf center from causing rot of the buds. In addition, the interval should not be too short; once every ten days or so is better, so as to avoid hypernutrition.

(5) The spraying method should be particular. Because fertilizer must be absorbed into the plant through the leaf stomata, and the leaf stomata are mainly on the underside of the leaves, foliar fertilizer should mainly be sprayed on the underside of the leaves. The nozzle should face upward, and the mist droplets should be fine, so that there are more opportunities to spray the underside of the leaves. At the same time, the spraying amount should not be too large; it is better if the leaves do not drip, to prevent the fertilizer liquid from accumulating at the leaf tips and causing fertilizer damage and tip burn.

(6) Spray less during the dormant period. During the low-temperature dormant period, the physiological activity of orchid plants weakens, and they generally do not absorb fertilizer. However, monopotassium phosphate, which improves cold resistance, and easily absorbed biological bacterial fertilizer can be sprayed about once every half month. At the same time, spraying a little foliar fertilizer on rootless and weak or diseased orchid plants can maintain their life and increase the survival rate.

(7) Be cautious about spraying growth hormones. Growth hormones do indeed have a very good effect on promoting plant growth and development, increasing the germination rate, promoting early maturity, and achieving increased yield, but their main function is to promote cell elongation. After application, excessive growth and even lodging may occur, which has an obvious impact on the health of orchid plants, so it is better not to use them.

(8) Foliar application should depend on the weather. On rainy days, air humidity is high, water is difficult to evaporate, and the fertilizer liquid stays on the leaf surface for a long time, which easily causes fertilizer damage. In high-temperature weather, especially in very hot weather with temperatures above 30 degrees, water evaporates too quickly, which will rapidly increase the concentration of the foliar fertilizer and cause fertilizer damage, so it is not suitable for spraying.

(9) Wash the leaves after spraying. After fertilizing in the evening, spray water once the next morning to wash off the fertilizer remaining on the orchid leaves, so as to avoid fertilizer damage after sunlight exposure. There are two ways to wash the leaves: first, directly spray the orchid leaves with clean water; second, add a fungicide to the water and spray with a sprayer, with a slightly larger spraying amount, achieving two goals at once.

(10) Foliar feeding cannot replace root fertilization. Foliar feeding is an auxiliary means of fertilization, a compensation for insufficient root absorption, and cannot completely replace root application, otherwise it will cause root shrinkage and poor growth.