How to fertilize overwintering spinach? Remember these five requirements

Properly control nitrogen fertilizer before overwintering. The standard for fertilizer and water management of overwintering spinach before winter is to ensure that the spinach grows 4 to 5 true leaves before overwintering. This is because spinach with 4 to 5 true leaves has the strongest cold resistance, while plants that are too large or too small are prone to freeze damage. Therefore, if the sowing date is suitable and enough fertilizer has accumulated, the application of nitrogen fertilizer should be properly controlled before overwintering to prevent excessive seedling growth, which reduces the accumulation of dry matter and sugars and leads to freeze damage. If sowing is too late or soil fertility is insufficient, topdressing with nitrogen fertilizer may be considered to promote seedling growth so that the spinach overwinters at a suitable seedling age.

Apply sufficient base fertilizer. Overwintering spinach has a relatively long growth period, so to prevent fertilizer deficiency, base fertilizer must be applied in sufficient amounts. Generally, organic fertilizer together with all the phosphorus and potassium fertilizer to be applied is used as base fertilizer and incorporated throughout the whole soil layer, after which the land is prepared and beds are made.

Strengthen fertilizer and water management after greening. The key to fertilizer and water management of spinach after overwintering and greening is to seize the right timing for topdressing. Topdressing for spinach is carried out along with irrigation. Topdressing too early after greening will lower the soil temperature and affect seedling recovery and growth, while topdressing too late will delay the growth of spinach. For overwintering spinach, it is generally more suitable to apply topdressing in two applications in mid-to-late March and early April, because at this time both the outside air temperature and soil temperature rise steadily.

Topdressing after overwintering must be carried out before the spinach bolts and flowers. This is because topdressing at this time can extend the time before spinach bolts and flowers, which helps increase the yield and quality of spinach.

Use ammonium nitrogen fertilizer with caution. Spinach is sensitive to ammonium nitrogen fertilizer. The production season of overwintering spinach coincides with the transition periods between autumn and winter and between winter and spring. At this time the soil temperature is low and the nitrification process in the soil is very weak, so it is best to use less ammonium nitrogen fertilizer and appropriately use more nitrate nitrogen fertilizer.