How to properly grow onions

Every gardener should know how to properly grow onions, because onions are very important in nutrition, because they are very good for health.
Onions are grown not only in open ground, but also in greenhouses, and there are amateurs who grow onions on the windowsill. Onions require soil that is rich in humus. Bright light is also very important for onions.
Little can be said about how to properly grow onions. To begin with, onions need to ensure good drainage in the soil. Therefore, the soil should have a minimum clay content. It is advisable to prepare the soil in the fall, dig it well, and remove unnecessary stones. In the spring, all that remains is to fluff up the top part of the soil, then apply mineral fertilizer with manure. It is best to sow onion seeds directly into open ground, but it is still advisable to germinate the seeds in advance at home.
It is also very common to grow onions from sets for those who do not like to use seeds. If you just want to grow onions, then you can do this all year round, not only in open ground in summer and spring, but also in winter in a greenhouse or on window sills. They begin to sow onions in open ground only after the last frost. The soil should be slightly moist, but there should be no rain. Dig a bed to a depth of 2 cm, with a distance of 30 cm from each other. After 20 days, seedlings appear. You can also sow onions under film; do this 3 weeks earlier.
If onions are grown from sets, that is, small onions that are obtained from seeds in the first year, then they are planted a little differently. Each set is planted at a distance of 10 cm from each other, with 30 cm between the rows and a planting depth of 1-2 cm. The upper part of the head should be at soil level.
Comments
I heard this fact about growing onions that at the very end it is very useful to sprinkle a little sand - for its rapid growth. And also useful for its “greenness”. Is this true?