Healthy Soil - Sarah Zettelmeyer, MS Sales Associate
Healthy soils have the following characteristics:
Sufficient, but not excessive, supply of nutrients
Large populations of beneficial organisms
No chemicals or toxins that may harm the crop
Resistance to degradation
Resilience when unfavorable conditions occur
Small populations of plant pathogens and insect pests
The best way to tell what your soil will need is by taking a soil test in the spring to your local extension agency through a local university (see Understanding Your Soil, and A Soil Sample Primer). You should repeat the soil test every three years depending on crop rotation. They can analyze the soil structure, PH balance, nutrient capacity and deficiency and give you suggestions on what needs to be applied. PH measures the acidity and alkalinity of a soil. The scale is 1-14. A PH of 7.0 is neutral, less than 7.0 is acidic, more than is basic (alkaline). The major impact of extremes in PH on plant growth is related to availability of nutrients for the plants, most vegetable crops prefer soil PH between 6.0 and 7.0.
Plants and soil form a complex ecosystem. Soil has a very diverse biology and forms a delicate relationship with the plants it sustains. In terms of nutrient management (or fertilization) we focus primarily on managing individual nutrients such as nitrogen, phosphorus, and potassium. Each one is valuable for different reasons and is needed in different amounts.
Nitrogen is part of the chlorophyll molecule that helps with photosynthesis. Nitrogen also helps produce amino acids for building proteins. A deficiency presents as stunted growth and yellowing begins in the leaf.
Phosphorus is important for healthy root systems, normal seed development, respiration, cell division. A deficiency presents as stunted plant growth and a purplish pigmentation in older leaves.
Potassium is responsible for regulation of water usage, disease resistance and protein synthesis. A deficiency presents as slow development and poor root systems.
Feeding Your Soil
There are two ways to feed your soil:
• Feed the plants directly, or
• Feed the soil directly in the spring or fall.
Feeding the Plants Directly
Feeding the plants directly involves using a soluble fertilizer or a dry fertilizer - nutrients that are readily available or “predigested” for plant use without the need for the soil to break it down to make it available to the plant. If your plants need a boost during the growing season, you can apply fertilizer directly to the plants. Most chemical fertilizers are synthesized from non-renewable resources, such as coal and natural gas; some are made by treating rock minerals with acids to make them more soluble. Soluble chemical fertilizers contain mineral salts that are readily available for uptake by plant roots. But these salts acidify the soil and do not supply a food source for soil microorganisms, and even repel earthworms! This action will eventually decrease the organic matter in the soil, making it less and less viable over time.
Liquid fertilizers are excellent for a nutrient boost. Apply them biweekly or monthly, considering the nutrient needs of the crop. Compost tea and seaweed extract are good examples of liquid fertilizers. Plants can absorb liquid fertilizers through both their roots and through the leaf pores in their foliage. Liquid fertilizers are usually diluted in water, and can be applied with a watering can to the roots and leaves, or through a pressure sprayer for foliar feeding. If you choose foliar feeding as your method, it is best to spray in the early morning or early evening when they won’t be exposed to the hot sun. Make a point to spray under the leaf where the pores are best able to absorb the nutrients. Foliar feeding can supply nutrients when they are lacking in the soil or the roots are stressed. It is especially effective for giving fast growing plants like vegetables an extra boost during the growing season. In either type of application, choose a day when no rain is in the forecast so the nutrients won’t wash away.
Feeding Your Soil Directly
If you feed the soil, the breakdown process will provide nutrients for the plants. Organic fertilizers serve as both nutrients for the plants and as soil conditioners. The most common way to apply dry fertilizers is to broadcast it and then rake it into the top 4-6 inches of topsoil. You can also add a half of a cup to planting holes when transplanting. During the growing season you can side dress the plants or along crop rows, it’s best to work that into the top 1 inch of soil.
You can purchase commercial blends of organic fertilizers which will provide balanced amounts of nitrogen, potassium and phosphorus or you can mix and match your own blend using the following ingredients: Blood meal or fish meal for nitrogen, bone meal is a good source of phosphorus, and kelp or greensand for potassium. The proportions should be 2 parts blood meal or 3 parts fish meal to 3 parts bone meal to one part kelp or 6 parts greensand.
An easy way for growers to feed their soil is by adding manure. Straight manure should be incorporated into the soil in the fall so that it has time to break down before you plant into it (too much nitrogen can have certain detrimental affects). You can also use high quality compost from a reputable source as an all purpose fertilizer to be applied right where the plants are growing and or tilled directly into the soil prior to planting.
Top of Page
Regardless of your choice of method, feeding the soil and fertilizing your plants will increase their production, ensure their health and disease resistance and keep your microorganisms working for you for years to come!