Fertigation and liquid feeding
Deliver soluble nutrients through irrigation water at growth-stage-appropriate rates while avoiding salt buildup in soil and containers.
10 min · intermediate
You will learn
- Mix liquid fertilizer at appropriate dilution rates
- Adjust feeding to plant growth stage
- Prevent and correct salt buildup in containers
What fertigation is
Fertigation combines fertilizing and irrigation by dissolving nutrients in water and applying them to the root zone. Liquid feeding provides immediately available nutrients, useful during rapid growth, fruit set, or recovery from deficiency. University of Minnesota Extension describes fertigation for high tunnels and drip systems where delivery is precise and foliage stays dry.
Dilution rates and frequency
Follow label rates for soluble fertilizers. Over-concentration burns roots and leaves. During vegetative growth, slightly higher nitrogen feeds are appropriate. During flowering and fruiting, shift toward formulas with more phosphorus and potassium and less nitrogen. University of Minnesota Extension recommends basing rates on soil tests and crop demand.
Timing by growth stage
Seedlings need only mild feeding once true leaves appear. Increase frequency as plants size up and again when fruit loads develop. Reduce feeding as plants approach end of season. In soil, alternate fertilized water with plain water to flush salts. Match feeding to visible plant growth stage rather than a fixed calendar.
Avoiding salt buildup
Repeated liquid feeding leaves mineral salts in soil, visible as white crust on pot rims or soil surface. Salts pull moisture from roots and cause leaf edge burn. Flush containers periodically by watering until excess runs freely from drainage holes. In-ground beds benefit from organic matter that buffers salts and from occasional deep irrigation.