> Next: Applying Organic Fertilizers
Supplementing Soil Nutrients
For best results you’ll apply fertilizer to your vegetables several times during the growing season. Vegetables need these nutrients so that they will grow, flower, and produce fruit, berries, roots, and foliage. In this section, you’ll find:
-
- Why supplemental feeding is vital for healthy and thriving vegetables.
- Which nutrients are water soluble and which are not, requiring different application methods.
- Which micronutrients and trace minerals vegetables need.
- How soil acid-alkaline balance (pH) changes how much nutrients are available for your vegetable plants.
- How do organic, natural, and synthetic fertilizers differ.
- How to choose and apply fertilizers and when to fertilize your vegetable garden.
- How much fertilizer to use to grow vegetables.
Understanding Fertilizers for Vegetables
Apply fertilizers to give your vegetable plants the extra nutrition they need to grow and thrive, and to set and ripen fruit.
These nutrients are naturally present in most undisturbed soils and those prepared for planting [see Sites and Soils]. Yet some soils lack enough of the nutrients needed to grow successful vegetables. Let’s understand why supplemental feeding is often necessary.
Because nitrate salts and some of the micronutrients and trace elements are water-soluble and other nutrients are used by the plants as they grow, soil that once was adequate can become exhausted in short order. This especially is true for soils used to grow plants in containers.
Mulch and Compost as Fertilizer
The best way to provide nutrients for your plants is by thoroughly preparing your soil prior to planting [see Incorporating Fertilizers and Amendments].
Throughout the gardening season, use organic mulches such as weed-free salt hay, compost, or straw for gradual feedings. These mulches and composts decompose slowly, release their nutrients into the soil, and replace most of the nutrients used by your plants.
Work mulch and compost into the soil as you cultivate your garden [see Cultivating a Garden]. If necessary, when you water add additional nutrients and trace elements by fertilizing with an organic liquid fertilizer such as fish emulsion or a tea made by soaking manure in water. Using this approach will provide low levels of the nutrients that your vegetables need and will still avoid any hazard of burning them by applying too much nitrogen fertilizer.
Natural, Organic, and Synthetic Fertilizers
Natural and Organic Fertilizer Options
Beside organic and natural fertilizer products, solid and liquid organic fertilizers, powders, or granules are other options when vegetable plants show signs of nutrient deficiency. Symptoms of a complete nutrient profile in garden soil include yellowing or purpling of foliage, stunted growth, lack of vigor, or growing susceptibility to pests or diseases.
Whenever these symptoms occur, choose and apply well-rotted or composted manures, bloodmeal, or manure-fortified composts of decomposed plant matter.
Avoid bonemeal made from ground, sterilized bones of cows, pigs, and other slaughtered animals because they may harbor infectious proteins called “prions” that could cause neural disease if inhaled or ingested. It is believed that prions are the cause of so-called mad-cow disease, or spongiform encephalitis, and also could be a health hazard to humans.
Most organic fertilizers are balanced with roughly equal amounts of the three nutrients—nitrogen (N), phosphorus (P), and potassium (K)—plus many micronutrients and trace minerals. Exceptions include mineral phosphate, guano, and raw manure, all of which have abundant nitrogen and cause rapid growth at the expense of flowers and fruit. It’s always best to use balanced, slow-release, low-concentration fertilizers for vegetables.
Synthetic Fertilizer Options
It is true that plants use both organic, natural fertilizers and those that are synthesized from petroleum by-products or other manufactured and natural chemicals in similar ways.
Synthetic fertilizers can be mixed to deliver precise amounts of nutrients, but they seldom contain the full range of nutrients, micronutrients, trace elements, and living soil organisms found in their natural organic fertilizer equivalents.
When you consider the environmental impact of using non-renewable resources and the energy consumed during manufacture, the benefit of choosing organic and natural fertilizer options is clear.
In many areas, agricultural runoff and leaching to groundwater of nutrients are serious concerns. Recycling manure products away from these areas for beneficial uses in your garden help avoid nitrates from entering the water supply.
For your vegetable garden, choose those fertilizers that will feed your plants and soils and that will make your produce the most nutritious while leaving the least footprint on the earth and ecosystems.
An exception may be made for foliar fertilizers. They are water-soluble, dry, synthetic concentrates that, when diluted in water and sprayed on plant foliage or stems, are absorbed directly and used for photosynthesis. Foliar fertilizers are first aid for plants afflicted by root-destroying diseases or infestations of pests. They’re a boon to help seedlings that are struggling become established and grow.