How do you grow directly sown watermelons with plastic film mulching for seedling production?

First, appropriately reduce planting density. Watermelons grown under plastic film mulching have lush vines and leaves, and the leaf area per plant increases, so planting density should be reduced by about 10% compared with the number of plants in open fields; second, cover with a thin layer of soil. Direct-sown watermelons under plastic film mulching have relatively higher soil temperature and good heat retention, giving better seedling emergence, so there is no need to use shallow sowing with deep soil covering; generally 1 to 2 cm is enough; third, release the seedlings in time. Begin checking emergence frequently 4 to 5 days after sowing. When the young seedlings push through the soil, break the film to release the seedlings as early as possible and seal the film around the seedlings with soil, so as to avoid scorching the seedlings at high temperatures.