Root retting causes and control measures of lettuce

Lettuce likes cold environment, now is a good time to grow lettuce, but in the lettuce seedling stage, many growers found that lettuce retting root phenomenon, resulting in a large number of lettuce seedling death. So what is the reason for lettuce retting? How to prevent and cure it? Let's take a look.

1. Retting root symptom

Raising seedlings in low temperature season is very easy to rett roots, the disease is not new roots or adventitious roots at all, the root bark is rust-brown, gradually rot, dry up, when the disease to a certain extent, the seedlings can be pulled out easily in the soil. At the initial stage of the disease, the symptoms were not obvious, and the aboveground stems and leaves grew slowly. The leaves gradually became yellowish green or milky yellow, the leaf margin began to wither and yellow, until the whole leaf wrinkled and withered yellow, the seedlings did not produce new leaves, and the whole plant withered and died.

2. The reason of retting root

Because the soil temperature is lower than 12 degrees, the duration is poor, overwatering, continuous rainy days, lack of light and other reasons are that the roots of seedlings will be in the state of low temperature, too wet and lack of light, and the respiratory metabolism of the roots will be hindered. Can not grow and develop normally, root absorption decreases, resulting in retting roots. In addition, retting roots will also appear when the soilless culture substrate is stagnant for a long time.

3. Prevention and control methods

To clean up the seedbed, to ensure that the soil is loose, flat, so as to avoid watering the bed area water, to ensure that the seedbed has sufficient light. When sowing should be fine, uniform, covering soil should not exceed 1 cm, before sowing to irrigate enough bottom water, the whole seedling stage to control watering, so as not to wet the bed, especially to prevent the soil from being wet for a long time. Three to five days before sowing, plastic film is first covered to increase the temperature of the bed soil, and then the plastic film is removed before sowing. If the seeds are sown without waiting for the low temperature to rise, the seeds will germinate slowly. After emergence, we should release air timely and properly, strengthen seedling exercise, and when planting at low temperature, we should water according to the hole, not flood irrigation, fertilization should be uniform, after root retting, plastic film can be covered, ground temperature can be increased, and soil can be loosened in time to promote diseased seedlings to promote new roots.

The above is the introduction of lettuce retting root causes and control measures, hope to help you, want to know more related knowledge, please pay attention to us.