Damping-off in seedlings: cause and measures

Damping-off: How to recognize the damage, prevent fungal infestation and protect your seedlings.

Seedlings bend, fall over and die

If your newly germinated seedlings suddenly hang their heads or fall over straight away, then a fungal infection may be to blame. Damping-off (syn.: damping-off, blackleg, root smut, seedbed rot) is responsible for the falling over and subsequent dying of the young plants. A whole range of different fungal pathogens, such as Fusarium and botrytis triggers this disease. If the seedlings lie completely on the ground and also have a sickly-looking stalk near the ground, then unfortunately the diagnosis is very likely to be damping-off. The sore spot may appear shriveled, brownish, or constricted. Heat-loving crops such as tomatoes, cucumbers, basil and chili are particularly frequently affected by damping-off. By the way: The pathogens are often able to kill cuttings.

Another cause of falling seedlings

In addition to the harmful fungi, there is often a completely different explanation for falling seedlings. This usually happens in the spring when the first vegetables for the gardening season are planted on the window sill. In poor light conditions, i.e. especially on the north window, the young plants then wither. When wilting, the plant does not get enough sunlight and grows a lot in length. All the growth power is then used for stem growth. Affected plants have small cotyledons and at the same time a very soft and long sprout. For example, if a tomato seedling is on a window sill with very little sunlight, the seedling will grow until it tips over. Such plants are generally more susceptible and usually snap completely after the first gust of wind. With a few precautionary measures, however, you can counteract the wilting: Wait until the sunny spring really arrives before cultivating your young plants. Even if you sow too close together, the small plants will rob each other of their valuable light. Incidentally, you can also slow down the Vergeilung with cool temperatures. Many young plants also feel comfortable at 15 to 18 °C. Seedling propagation should therefore not take place in a warm living room (25 °C) in poor light conditions. As a rule of thumb, you can remember: the warmer a plant is, the more light it needs.

Preventive measures against damping-off

Since infested young plants can hardly be saved, attention should be paid to prevention. If a few culture tips are taken into account, damping off will no longer be a problem. Because the harmful fungi like a humid and warm environment at the same time, this combination should be avoided. The temperature has to be adjusted to the needs of the seedlings, and they usually like it warm. Above all, the humidity should be reduced again and again through regular ventilation. Many hobby gardeners really ensnare their young plants. The young plants are often watered too much or constantly wetted with water from the spray bottle. Through such a cultivation management, mushrooms also find optimal living conditions. To keep the fungi away from our sensitive seedlings, we have put together a few tips for you:

1. Stay away from the spray bottle! Plants, including young plants, do not have to be wet all the time. As a rule, most plants do not like constant moisture at all.
2. If you use a mini greenhouse for cultivation, don't forget to ventilate it regularly. As a rule of thumb, the older the young plant, the more often and longer it should be aired. Unfortunately, there is no general ventilation time, a bit of tact and practice is required here.
3. Ideally, the plants should only be watered from below. On the one hand, this keeps the plants dry and, on the other hand, the top layer of soil does not get too wet. There, on the top layer of soil, many of the harmful fungi develop particularly well. It is also sufficient for most young plants if the top layer of soil is slightly damp. Penetrating wetness only does harm here.
4. The right choice of soil plays a role that should not be underestimated for seedlings. It is generally recommended to use potting soil such as ours Plantura Organic Herb & Seed Soil to use. It is low in germs and nice and fluffy, which means that excess water can drain away quickly (of course, this is only possible with existing drainage holes!). If you want to be on the safe side, you can also steam your soil to kill possible fungal pathogens. This works in the microwave and takes approx. 15 minutes or put the soil in the oven for 30 minutes and 200 °C. In order for the damping to be successful, the soil must not be dry during the sterilization process.

Combat damping-off properly

While it would be nice if infected seedlings could still be saved, this is not the case. The small plants are still far too sensitive to regenerate after a fungal attack. For this reason, you should remove diseased young plants immediately so that the fungal disease cannot spread further. As a precaution, sow a few more seeds, then you can live with the loss of a few young plants.