How to top-dress red choy sum? Mastering these key points is crucial
Many people are certainly familiar with red choy sum on the market; it is a common vegetable in the south, and in rural areas basically every household grows some. Its texture is tender, its nutritional value is high, and it can also stimulate appetite. Right now is the critical period for red choy sum growth and also an important stage for top-dressing, so how should red choy sum be top-dressed? Let us find out together.
1. Seedling-promoting fertilizer
Generally about one week after transplanting, once the seedlings have survived, new roots have already grown out, and seedling-promoting fertilizer should be carefully applied to speed up seedling growth and development. At this time, the top-dressing is mainly nitrogen fertilizer, generally applying 5-10 kg of urea per mu, while paying attention to concentration, because the seedlings are young and tender, the root distribution range is small, and they are sensitive to fertilizer concentration. High fertilizer concentration can cause seedling burn, so it is recommended to apply it dissolved in 1000 liters of water, or pour dilute manure water around the root zone.
2. Rosette fertilizer
About 20 days after the first top-dressing, the seedling leaves have fully grown, and large primary rosette leaves will also grow. At this time, rosette fertilizer needs to be applied heavily to meet the needs of red choy sum primary rosette leaves and main stem growth and development. It is best to apply both quick-acting fertilizer and long-acting fertilizer, such as cake fertilizer, manure fertilizer, compound fertilizer, urea, etc. It can be applied by opening furrows between the beds, scattering the fertilizer into the furrows, and then covering it firmly with soil, generally at a standard of 30 kg compound fertilizer + 1 kg urea per mu.
3. Flower stalk-promoting fertilizer
Flower stalk-promoting fertilizer is generally applied after the main flower stalk is harvested. It can be applied by digging holes on the outer side of the plant, then covering the fertilizer with soil from cleaning the furrows. Per mu, 10 kg urea + 10 kg potassium chloride can be used. Its main role is to supply what secondary rosette leaves and side stems need for growth and development.
4. Flower stalk-preserving fertilizer
After the side stems are harvested, according to the plant's growth condition, fertilizer should be applied once every 3-5 harvests, with 10 kg urea per mu, to maintain the fertilizer demand of secondary rosette leaves and regenerated rosette leaves and ensure the flower stalks bolt smoothly. Under good fertilizer and water conditions, the flower stalks of these two grades have better market value; otherwise, the bolted stalks are thin, weak, and short, with low market value.
The above is an introduction to the key points for top-dressing red choy sum. We hope it helps you. To learn more related knowledge, please stay tuned to us.