Why can't watermelons hold fruit? (What should I do if greenhouse watermelons can't hold fruit?)

A large area of ​​watermelons have experienced problems such as few fruits, the inability to set fruits, and low fruit setting rates. There are even many watermelon vines that should have set fruits normally, but now there are "no fruits" on them, especially the watermelons grown in greenhouses.

Generally, there are four main reasons why watermelons cannot keep their shape: one is adverse climatic factors, two is improper cultivation and management, three is improper water and fertilizer management, and four is other human factors.

In the process of greenhouse watermelon cultivation, methods such as pruning, vine pressing, vine sorting, artificial assisted pollination, melon selection, melon retention, and the use of hormones can be used to increase the fruit set rate .

Remove the buds and leave the vines

After planting watermelons, in order to increase the number of leaves in the early stage, do not remove the buds too early. Allow them to grow naturally, so as to increase the number of leaves as soon as possible and promote the healthy growth of the vines.

When the vines grow to more than 60cm, you can start to remove buds and branches. When removing buds, keep four large vines to allow the vines to continue growing, and cut off the rest of the small vines.

Arrange hanging vines

Select two relatively large vines from them, and use the melon hanging line to hang the vines. When hanging the vines, they should be wound in an S shape so that the vines bend and climb upwards. This can ease the growth of the vines and improve the utilization of space.

Pruning secondary vines

(1) For the secondary vines growing between the leaf axils, except for the one at the fruit bearing node, which has 3-4 leaves, all other vines should be cut off to avoid too many growth points, which will cause nutrient deficiency, affect light conditions, and reduce the fruiting rate of watermelons.

(2) For the other two vines, pinch off the top of one vine when it has 8 to 10 leaves, and then trim off the secondary vines twice. For the other vine, also trim off the secondary vines twice in time, and let it grow freely on the ground between the rows.

During artificial pollination, the growth point and side vines also need to be removed to reduce competition for nutrients and facilitate watermelon setting.

Reasonable fertilization

When applying topdressing, the principle of light and frequent application should be followed.

1. Seedling fertilizer

Fertilization can start when the melon seedlings have established roots and shown true leaves. Apply human and animal manure every 10-15 days or so, and mix in some urea. The amount used per mu is about 15-20 dan of human and animal manure and 3-5 jin of urea.

2. Group fertilizer

When the melon seedlings grow to 5-6 leaves, apply 100-200 kilograms of decomposed cake fertilizer and 10-20 dan of human and animal manure per mu.

3. Fruit-enhancing fertilizer

When the watermelon grows to the size of an egg, apply 100-200 kilograms of cake fertilizer and 10-20 dan of human and animal manure per mu.

4. Melon fertilizer

When the watermelon grows to the size of a bowl, apply 15-20 kilograms of urea and 5-8 kilograms of potassium fertilizer per mu.

5. Melon Fertilizer

After the first batch of watermelons are picked, in order to prevent premature aging of the seedlings and provide nutrients for the second and third batches of watermelons, 20-25 kilograms of urea can be applied per mu.

pollination

If the watermelon blooms on a sunny day, insects can pollinate it and the pollination success rate is relatively high, so there is no need for manual pollination.

If it rains frequently, fewer insects will come out, so artificial pollination is needed. First, shake the pollen on the male flowers onto the female stamens. If the flowers wither, they will not bear fruit.