Urea is effective in a few days.

Spraying urea usually takes 7-15 days to take effect. It is necessary to pay attention to forbidding spraying urea before rain to avoid burning seedlings or losing fertilizer, which should be carried out in the early morning or afternoon; generally cereal crops require a concentration of 1.5% Mel 2%. If it is sprayed during the flowering period, the concentration needs to be appropriately reduced. 0.5% concentration is appropriate for apple, pear and other fruit trees.

Points for attention in foliar spraying of urea:

1. It is forbidden to spray in hot weather or before rain to avoid burning seedlings or losing fertilizer. It is appropriate to spray in the early morning or afternoon every day, and spray again every 7-10 days.

two。 When spraying cereal crops or crops with smooth leaves, it is best to add 0.1% adhesive (such as washing powder, washing), etc. Otherwise, the effect is not good.

3. For urea used for spraying, the content of biuret should not be more than 0.5%, if too high is harmful to the leaves.

4. To master the concentration of urea, general cereal crops require a spray concentration of 1.5% Murray 2%, which is even lower when sprayed at flowering stage. The spraying concentration of leafy vegetables and cucumbers is 1% Mur1.5%, and that of tomatoes is 0.3%. 0.5% is suitable for apple, pear, grape and other fruit trees.

Summary: the above content is for you to sort out the introduction of how long the foliar spraying of urea is effective, hoping to help the needy partners.