Water Soluble Fertilizers in Drip Irrigation: Which Grade at Which Stage

Water soluble fertilizers (WSF) dissolve completely, so they can be fed through drip lines or sprayed on leaves without clogging. The real advantage comes from matching the grade to the crop's growth stage — the crop needs different nutrient ratios at planting, vegetative growth, flowering and fruit development.

Early stage: root establishment

Phosphorus supports root development. A high-phosphorus grade such as Kheti MAP 12:61:00 (N 12%, P2O5 61%) is commonly used in the first weeks after planting or transplanting.

Vegetative growth

A balanced grade supports leaves and shoots. Kheti NPK 19:19:19 (N, P2O5 and K2O 19% each) is the most widely used all-round grade for this stage.

Flowering

Phosphorus and potassium support flower initiation and fruit set. Kheti MKP 00:52:34 (P2O5 52%, K2O 34%) is nitrogen-free, which helps avoid excess leafy growth at flowering.

Fruit development and quality

Potassium drives fruit size, colour and sugar content. Kheti K-Nitro 13:00:45 (N 13%, K2O 45%) suits early fruit growth, while Kheti K-Xpert 00:00:50 (sulphate of potash, K2O 50% + S 17.5%, chloride free) suits later fruit filling and quality. Kheti Calmax (N 15.5% + Ca 18.5%) supplies calcium for firmer fruit and better shelf life.

Dose (as per label)

For all the grades above, the label dose is: foliar spray 1-2 g per litre of water; drip irrigation 2-5 kg per acre per application, or as advised by an agricultural expert. Split the requirement into regular small doses rather than one large dose.

Important mixing rule

Do not mix calcium nitrate (Calmax) in the same tank with phosphate or sulphate fertilizers such as MAP, MKP or SOP — they react and form insoluble deposits that can clog drippers. Feed calcium separately, in its own tank or on a different day.

Always follow the directions on the product label and consult a local agronomist for crop-specific schedules.

Frequently asked questions