When to Fertilize a Pomegranate Tree? Detailed Guide to Fertilizing Times and Methods

Pomegranate Tree Fertilizing Times

Mid-May and mid-October. Generally, quick-acting nitrogen fertilizer should be applied before flowering in early to mid-May, together with phosphorus fertilizer, to promote vegetative growth. During the post-flowering fruiting stage and the young fruit swelling stage, apply n, p, k compound fertilizer as a top dressing to promote rapid growth of the young fruit and also promote flower bud formation. At the same time, during the growing season, multiple foliar top dressings should also be carried out, spraying the leaves with 0.3%-0.5% urea or 1% diammonium phosphate. When trace element deficiency symptoms appear, micro-element fertilizer should be sprayed promptly.

In mid-September the fruit ripens in large quantities and is harvested successively. After harvest, carry out autumn pruning carefully and apply base fertilizer promptly, mainly farmyard organic fertilizer. Autumn base fertilizer application should be completed before mid-October, and fertilizing in winter must be avoided.

Pomegranate Tree Fertilizing Methods

These can be divided into two forms: soil fertilization and foliar (leaf) top dressing, with soil fertilization as the main method and foliar top dressing as a supplement.

(1) Soil fertilization is the application of fertilizer to the root zone of the fruit tree to facilitate absorption. The fertilizing effect is closely related to the fertilizing method. It should be determined according to the terrain, topography, soil texture, fertilizer type, and especially the root distribution. The horizontal root system of the pomegranate tree is generally concentrated around the outer edge of the canopy projection, so the depth and breadth of fertilization should change year by year from inside to outside and from shallow to deep as the tree age increases.

(2) Foliar (leaf) top dressing is the even spraying of a fertilizer solution of a certain concentration onto the leaves of the pomegranate tree. First, it can increase tree nutrition, raise yield and improve fruit quality; generally it can increase the fruit-setting rate by 2.5%-4%, increase fruit weight by 1.5%-3.5%, and increase yield by 5%-10%. Second, it can promptly supplement the trace element needs of some deficiency symptoms. The advantages of foliar fertilization are fast absorption, fast response, and obvious results: generally absorption can occur 15 minutes to 2 hours after spraying, and the leaves show an obvious response to the fertilizer elements in 10-15 days. It can avoid the shortcoming of many trace elements being easily fixed by the soil after being applied to the soil, which reduces fertilizer efficiency.

After foliar fertilization spraying, the leaf response to the fertilizer elements gradually disappears in 25-30 days, so it can only be a supplement to soil fertilization. The large amount of nutrients needed for the growth and fruiting of the pomegranate tree still must be supplied mainly through soil fertilization.

During foliar fertilization, the nutrients of the fertilizer mainly enter the leaves through the stomata and cuticle on the leaves, and then move to the various organs of the tree. The underside of the leaf has more stomata and larger intercellular spaces than the upper surface, which is favorable for penetration and absorption. The optimum temperature for foliar fertilization is 18°C-25°C, so in summer the best spraying times are before 10 a.m. and after 4 p.m. The atomization should be fine and the spraying even, with special attention to increasing the amount of fertilizer adhering to the underside of the leaves.

Generally, fertilizers that can dissolve in water can be used for foliar top dressing, and different fertilizer varieties should be selected according to the purpose of fertilization. Foliar fertilizer can be applied together with chemicals for pest and disease control. However, when spraying in a mixture, care must be taken not to reduce the efficacy of the pesticide or the fertilizer. For example, alkaline pesticides such as lime sulfur mixture and Bordeaux mixture cannot be mixed with superphosphate, manganese, iron, zinc, molybdenum, etc.; while urea can be mixed with pesticides such as Bordeaux mixture, dichlorvos, phoxim, arsine, zinc, and thiram. The concentration for foliar spraying must be accurate to prevent pesticide damage or fertilizer damage. A small amount of wetting agent can also be added during spraying, such as soap solution, washing powder, saponin oil, etc., which can make the fertilizer and pesticide adhere to the leaf surface and improve the effect of fertilizer absorption and pest and disease control.