Most fertilizers (and many soil amendments) show this formula somewhere prominently on the package: N-P-K. This shows the ratio of the three most important plant nutrients, Nitrogen, Phosphorus, and Potassium. Potassium gets a ‘K’ because of its name on the periodic table of elements (Kalium). These three elements are fundamental to the development and success of all plants to varying degrees. A fertilizer with a rating of 4-4-4 is considered “balanced” because it provides each of these major nutrients in equal proportion.
Nitrogen (N) is necessary for the growth and maintenance of all proteins. A lack of nitrogen will often result in stunted growth, or sudden yellowing of the plant from the ground up. Nitrogen is also an essential food for soil microorganisms which convert organic matter into nutrient forms that are available to plants.
Phosphorus (P) is essential for photosynthesis — the process by which plants convert light energy into food. It’s also needed for the development of flowers, fruits, and seeds.
Potassium (K) helps plants regulate the amount of water in their cells. This is key for structure and strength in the plant’s tissues, and important for overall health and resistance to pests and disease. Potassium helps build strong root systems, particlarly in plants that produce bulbs and rhizomes.
Nitrogen, phosphorus, and potassium are the Primary Macronutrients. These three elements are crucial to plant health, but they are not alone. Other elements like calcium, magnesium, and sulfur also play integral roles in plant development and health. These are the Secondary Macronutrients.
Micronutrients are elements that are used in minute quantities by most plants, but also play important parts in the health and robustness of vegetable tissues. These include boron, copper, iron, manganese, molybdenum, zinc, and chlorine. Kelp and fish based fertilizers are excellent sources of micronutrients. Always follow the instructions for diluting these products to the correct level. Too much boron or zinc, for instance, can have detrimental effects on plant growth.
We encourage the use of organic fertilizers to increase biological activity in soil and provide nutrients to crops. Plants take up and consume soil nutrients, so at each harvest, you are literally removing some nutrients from the soil. Organic fertilizers are used to replenish those soil nutrients, or to amend soil when one or more specific nutrient is lacking.
For most gardeners, it is safe to assume that even poor soil will benefit from the application of organic matter (well-rotted manure or compost), and some All Purpose 4-4-4 fertilizer. With these simple applications, you should be able to grow healthy crops. We are very pleased with the results we have achieved with Gaia Green’s All Purpose blend, as well as the others offered here.
Minerals Really Matter
It can be tempting to think of Organic Gardening as simply gardening in a lot of organic matter. Some gardeners make the mistake of over applying organic matter such as compost and manure at the expense of the mineral content of soil. This can result in stunted plants that never really get past the seedling stage, or show pale leaves and weak flower/fruit formation.
Perfect gardening soil is called Loam. Loam is a balanced mixture of sand, silt, and clay particles – and these are all minerals. Loam is fluffy, and allows both water and oxygen to penetrate deep to the roots of plants. It also allows for a rich ecosystem of soil microbiology to develop. It is this ecosystem that is literally fed when we integrate organic matter into the soil.
Organic matter (in the form of manure, compost, leaves, etc…) should only make up around 15 to 20% of soil for crop growing. So every time organic matter is added to the garden, so too should minerals be added. There are a number of ways to deliver minerals to depleted soils, but we think the best method is the use of Glacial Rock Dust. It cannot be over-applied, and it will produce rich, ecologically healthy, and highly fertile soil over time.