Seedlings fail to grow and then fall over? The reason is actually very simple

Seedling damping-off is most likely to occur shortly after the seedlings emerge. At first, the base of the young seedling stem is water-soaked and light brown, then becomes thin and thread-like, and the seedling quickly falls over onto the ground. At the beginning, only a few individual seedlings are affected, but then, with these as the center of infection, it spreads rapidly outward, causing patches of seedlings to collapse. When the seedbed is damp, white cottony mold grows on the surface of the diseased seedling remains and on the nearby soil surface, and finally most of the diseased seedlings rot or dry up.

1. Causes of damping-off

The pathogen overwinters in the soil and can survive for a long time. The pathogen is mainly spread by seedbed irrigation water, contaminated manure, farm machinery and tools, etc. It is prone to occur when the temperature is unsuitable and water accumulates on the bed surface after irrigation. Insufficient light and thin, weak seedlings also make it more likely to occur. Therefore, the amount of water should not be too large; watering the seedlings can cause them to fall over. It is also possible that certain substances in the water are too concentrated, causing the roots to lose water. Light should not be too shady, which causes the stems to grow too fast and too thin, producing leggy seedlings and spindly seedlings that cannot support themselves and fall over.

2. Solutions

Seed germination should be promoted, and sowing density should be moderate;

Apply less nitrogen-containing fertilizer and more potassium- and phosphorus-containing fertilizer, because potassium can promote thick, sturdy stems and make lavender less prone to falling over;

Do not expose them to direct sun, to prevent dehydration and death and reduce water-loss damping-off caused by sun exposure. They can be placed outdoors with a shade net for cover, but some sunlight can still pass through. This way, flower seedlings are less likely to become leggy, and photosynthesis is enhanced to promote thick, sturdy stems;

Keep the potting soil dry rather than moist, which is good for root growth and makes the stems and leaves grow more evenly. Switching to bottom watering from below the pot will be a bit better;

For the vegetable field, choose a plot with higher terrain, a lower groundwater level and good drainage for the bed, and use disease-free field soil for the bed soil;

Bed soil can be disinfected. For each square meter of bed soil, use 8—10 grams of a 1:1 mixture of 50% carbendazim and 50% thiram, or mix 10 grams of 30% Miaojundi with 15-25 kg of dry fine soil to make medicated soil, and mix it into the bed soil before sowing;

Once the seedbed is affected, chemical control can use a 500-fold dilution of 25% metalaxyl, or a 200-fold dilution of 40% aluminum ethylphosphonate for spraying.