Fertilizer, whether organic or synthetic, is usedtosupply nutrients to plants when they need them.
Fertilize based on soil testresults and plant needs.
Nutrient needs vary between plant families and species. For example, leafy greens require more nitrogen than beans and peas.
Vegetable crops generally need nutrients most when getting established and during flowering and fruiting.
Vegetable fertilizer tips
Refer to the label directions of the fertilizer you select for the amount to use.
Fertilize spring seedlings and transplants with a soluble fertilizer mixed with water then switch to a granular vegetable fertilizer as the plants grow.
Mix dry fertilizers into the top 2-4 inches of soil. Water-in fertilizers after application if rainfall is not expected.
Nutrient availability is reduced by competing weeds, leaching and run-off, and cool spring soil that limits nutrient release from organic matter.
Fertilize the actual planting area where roots will be growing, not walkways.
Slow growth, stunting, pale leaves, and low yields may indicate a need to fertilize. But these symptoms can be caused by other factors, such as crowding, low sunlight, compacted soil, and root-knot nematodes.
Sidedress established plants (apply fertilizer next to plants) when needed. Pull mulch away before side-dressing and replace it afterward.
Use nitrogen-only fertilizers (organic fertilizers) rather than complete fertilizers (contain N, P, and K) if a soil test report indicates high levels of P (phosphorus) and K (potassium).
One cup (8 ounces) of a dry organic fertilizer like cottonseed meal weighs approximately 0.33 lb. (5 ounces).
One cup (8 ounces) of a synthetic granular fertilizer like 10-10-10 weighs approximately 0.50 lb. (8 ounces).
Boron is an important micronutrient that is sometimes deficient in sandy soils causing disorders in some vegetable crops. Incorporate 6-7 tablespoons of Borax per 1,000 sq. ft. of vegetable garden area each spring where soils are sandy.
Overfertilizing vegetable plants (especially nitrogen) can produce lush, green plants but little fruit.
Both chemical and organic fertilizers can be overapplied and burn plants or stimulate leaf growth at the expense of fruit.
An excerpt from the article “Fertilizing Vegetables“, by Jon Traunfeld, Director HGIC, Extension Specialist, Fruits, and Vegetablescourtesy of the University of Maryland.