How to water flowers in different seasons, air damage and prevention of flowers in greenhouse

Flowers in plastic greenhouses and greenhouses often grow in airtight conditions in the depths of winter. Because the temperature in the greenhouse is high, the humidity is high, and the ventilation is poor, the flowers in the growing period are easily harmed by harmful gases, which makes the plants grow poorly, and the serious ones will wither and die after a period of time. Therefore, special attention should be paid to the occurrence and prevention of harmful gases in greenhouse and greenhouse. Several common types of gas damage

1. Ammonia poisoning: when undecomposed animal manure, cake fertilizer or excessive urea, ammonium bicarbonate and other fertilizers are applied in the greenhouse, a large amount of ammonia will be produced in fermentation decomposition. When the concentration of ammonia is higher than 5ppm, ammonia will invade the cells from the leaf stomata, destroy chlorophyll, make the damaged leaf tip produce water stains, the leaf edge turns yellow and brown, and then the leaf dries up. Ammonia damage mostly occurred in the leaves on the outside of the plant, especially in the new leaves.

2. Nitrite gas poisoning: excessive application of ammonium nitrate in the greenhouse hindered soil nitrification and caused nitrite gas to accumulate massively. When the concentration reached 2ppm, poisoning symptoms appeared. It often occurs on the leaves in the middle of the plant, and the damaged leaves appear irregular green-white spots, and the whole plant dies when the concentration is too high.

3. Sulfur dioxide poisoning: sulfur dioxide gas produced during heating generally invades from the stomata on the back of the leaves, destroys chloroplasts, dehydrates the tissue, forms white spots in the damaged parts, and then dries up. In severe cases, the whole leaves turn green and reticulate, and the veins dry up quickly.

4. Carbon monoxide poisoning: when the greenhouse is heated by coal fire, a large amount of harmful carbon monoxide is produced due to incomplete combustion or poor ventilation. When the concentration reaches 2 to 3ppm, it is harmful to some herbaceous flowers. At the beginning of the damaged leaves, the leaf surface and vein tissue became watery, then whitened and yellowed, and finally became irregular necrotic spots.

5. Sulfite poisoning: ammonium sulfate, potassium sulfate and uncooked cake fertilizer are applied in large quantities in the greenhouse to decompose to produce sulfur dioxide gas. When the gas meets water droplets, it will form sulfite, which directly destroys the chlorophyll of the leaves. The cells near the stomata of the poisoned leaves showed round or rhombic white "smoke spots" after necrosis, and gradually withered and fell off.

6. Film poison gas poisoning: the plastic film with diisobutyl phthalate or n-butyl phthalate as plasticizer is easy to volatilize ethylene, propane, trichloropropane, tetrachlorohydrin and other toxic and harmful gases at high temperature, when accumulated to a certain concentration, it will poison some flowers and make the leaves lose green yellowing, whitening, dry and wrinkled.

Comprehensive prevention and control of common air damage

1. Rational fertilization: the fertilization of flowers in greenhouse should be based on high-quality soil fertilizer, properly increase phosphorus and potassium fertilizer, and apply less nitrogen fertilizer as much as possible. The application of nitrogen fertilizer is mainly based on base fertilizer and supplemented by topdressing. Do not apply cake fertilizer and human feces and urine, especially do not apply chemical fertilizer containing nitrogen and sulfides, when fertilizing is needed, it should be carried out strictly in accordance with the principle of "small amount and many times" topdressing. If the greenhouse is used to raise seedlings, as long as the seedlings grow normally, they can not be fertilized. If the seedlings are weak, foliar fertilizer should be sprayed at 11:00 on a sunny day in winter and after ventilation in spring.

2. Timely ventilation: without affecting the temperature, increase the time of ventilation as much as possible to discharge toxic and harmful gases and make the gas composition in the shed close to that outside the shed. The door is usually opened for ventilation from 8 am to 9 am in winter. Spring ventilation time is gradually extended, especially at noon do not forget to open the door for ventilation, cloudy days as far as possible at noon ventilation, even if rain and snow, but also at noon for a short period of ventilation, in order to minimize toxic gases in the shed and reduce air humidity.

3. Careful management to reduce the source of poison: when the greenhouse is heated by coal fire, special attention should be paid to the full combustion of fuel, and chimneys should be installed on the stove to export harmful gases out of the shed, and pay attention to ventilation to prevent harm caused by carbon monoxide and carbon dioxide.

4. Choose non-toxic plastic film: try not to use toxic plastic film with plasticizer or stabilizer, but choose ethylene synthetic resin plastic film to reduce toxic sources and prevent harm.