Potassium dihydrogen phosphate to raise orchids is not a magic trick, I believe most orchid friends have used. It is used in the spring to promote seedling growth, and in the autumn it is used to breed flower buds. Potassium dihydrogen phosphate is a water-soluble phosphorus and potassium fertilizer that is mostly used for foliar spraying of plants, which is more quick-acting and safer than soil fertilization.
Generally speaking, potassium dihydrogen phosphate for the conservation of orchids is not recommended for use in winter. And potassium dihydrogen phosphate is enough to spray three or four times a year, twice in the spring plus one or two times in the autumn, and there is no need to spray orchid leaves in the winter. However, some Lanyou inadvertently forgot to spray phosphorus and potassium fertilizer in the early stage of management, and only then did they think. If sprayed effectively, it does improve the overwintering ability of orchids.
So, can you still spray potassium dihydrogen phosphate on orchids in winter? Before answering this question, we must first know how potassium dihydrogen phosphate acts on orchids. Only by understanding its principle can we better grasp the use of it.
Potassium dihydrogen phosphate is dissolved in water and sprayed on the leaves, then absorbed by the pores of the orchid leaves, and then when the orchid leaves are photosynthetic, the phosphorus and potassium elements in it are converted into plant growth energy, which is absorbed and stored by the orchid plant. Two key conditions are mentioned here:
First, the breathing capacity of the leaves
Second, photosynthetic efficiency
a: These two conditions are completely problematic in the spring and summer, and the breathing capacity of orchid leaves is related to the ambient temperature. Usually between 20 degrees and 28 degrees Celsius in the ambient temperature, orchid leaves have the strongest respiratory ability, and fade below 30 degrees and below 15 degrees. The temperature in winter is obviously not so qualified, but it does not mean that it is completely unusable.
As long as the ambient temperature is about 15 degrees, taking into account the temperature difference between day and night, if the temperature is 10--- 17 degrees for three consecutive days, potassium dihydrogen phosphate can be sprayed. Why is it required for three consecutive days? Because after the foliar fertilizer is absorbed by the leaves, there is also a process of decomposition and utilization. Another thing to note is that the concentration of potassium dihydrogen phosphate used in winter must be lower than that in spring and summer.
Because the temperature decreases, the solubility rate of potassium dihydrogen phosphate will also decrease. The time to wait for absorption after spraying the leaves will also be extended, and if the concentration is the same as in the spring and summer, crystals may form, resulting in blocked leaf breathing and side effects. For example, in the spring and summer, the potassium dihydrogen phosphate I use is 800 times the liquid spray leaf; in the winter, it is reduced to about 1500 times.
b: In addition to temperature and concentration, another condition that directly affects the absorption efficiency of potassium dihydrogen phosphate is photosynthesis. In the spring and summer, I recommend spraying potassium dihydrogen phosphate, which is recommended to work in the evening on sunny days, so that the leaves have more absorption time (enough temperature) at night, and the next day in the sun, the nutrient synthesis efficiency will be higher.
But in the winter, this operation is obviously not suitable, because the temperature at night has dropped to about 10 degrees or even lower. At this time, it is necessary to strive for more light, as mentioned above, the concentration of potassium dihydrogen phosphate sprayed at this time should not be too high, but also to avoid evaporation too quickly in the sun and lead to crystal formation.
The best time to spray is in the morning on a sunny day, when the dew on the orchid leaves has just dried, spray in the sun. What is the amount of spraying? A small trick is to not condense into water droplets. The potassium dihydrogen phosphate solution sprayed in this way can be basically completely dry within an hour. Leave the rest to the sun, which converts fertilizer into energy.
In fact, this article talks about two basic conditions, temperature will affect the respiratory capacity of orchid leaves, and sunlight is related to nutrient conversion. As long as these two basic conditions are mastered, orchids can still spray potassium dihydrogen phosphate even in winter. Of course, if the pre-management is already in place, then there is no need at this time.
The above is only some of the views that the good farmer himself has experienced and seen, and the views may be one-sided and limited, only for Lan You's reference.