In this post, I will share the fundamental elements to a healthy, thriving lawn and garden and the key is in understanding soil health and plant nutrition.
Understanding soil health and plant nutrition is key to a vibrant, healthy and productive lawn & garden. Soil nutrients, soil microorganisms & fungi and soil structure are fundamental in supporting optimum plant vitality and growth. Understanding the roles macro and micro-nutrients play during the various growth stages of your plants life cycle as well as the benefits of adding organic matter such as compost or manure, will help support a thriving garden. Below I outline in detail the function of the macro and micro-nutrients in plant health and organic sources of these nutrients and also discuss the benefits of aged manure and compost on soil and plant health.
When selecting nutrient amendments, I always prefer to use organic sources rather than synthetic fertilizer/amendment products to improve soil structure and provide plants with nutrients essential to their growth, productivity and well-being.
Nutrient functions in plants:
Macro-nutrients include the 3 primary nutrients of Nitrogen, Phosphorous and Potassium (N-P-K) and secondary nutrients of Calcium, Magnesium and Sulphur. Macronutrients are essential for plant growth and a good overall state of the plant. Plants consume the primary N,P,K nutrients in larger quantities while their intake of secondary macro-nutrients is lower.
Micronutrients are equally important for plant growth but required in smaller quantities. Plants require a proper balance of all the essential nutrients for normal growth and optimum yield. Micro-nutrients include iron, manganese, boron, molybdenum, copper, zinc, chlorine, and cobalt.
Each of the above nutrients has a distinct function, necessary for nourishing the plant. A shortage in any of them leads to deficiencies and varying adverse effects on the plant’s general state, depending upon which nutrient is missing and to what degree.
Nitrogen (N): Nitrogen is key for leaf development and chlorophyll production, making it essential for young plants and leafy vegetables. It helps give plants that vibrant green color and encourages robust growth. Fertilizers high in nitrogen are often used for grass or other plants where green foliage growth is more important than flowering. A nitrogen deficiency results in a loss of vigor and color. Growth becomes slow and leaves fall off, starting at the bottom of the plant.
Important tip: Using too much nitrogen will produce foliage at the expense of fruit and flowers.
Phosphorous (P): Important for healthy root structure development and shoot growth. An essential nutrient for plants coming into spring growth in particular. Great to use at planting time for all plants including bulbs. A shortage of phosphorous results in a late, deficient flowering, browning and wrinkling of the leaves, and a lack of vigor in general.
Potassium (K): It is essential for fruit and flower production. Potassium contributes to the overall health and vigor of plants. It is known to help strengthen plants ability to resist disease and assist in the movement of water and nutrients in the plant. Use as the plant is coming into flower or setting fruit. When there is a potassium insufficiency, dark spots appear on the leaves.
Magnesium (Mg): Magnesium plays a key role in the photosynthesis process and its deficiency is detrimental to plant growth.
Calcium (Ca): A secondary or macronutrient needed for growth and development of plants under both non-stressed and stress conditions. It’s important in cell wall and membrane stability.
Boron (B): The main functions of boron relate to cell wall strength and development, cell division, fruit and seed development, sugar transport, and hormone development in plants. Boron becomes available as organic matter decomposes.
Organic nutrient amendments:
Organic fertilizers and amendments are derived from plant or animal sources and contain plant nutrients in organic form. They contain macro and micro nutrients in various quantities depending upon the product. I always opt for slow/timed-release organic amendments that deliver nutrients to the plant when they need them and provide longer term results rather than synthetic fast release fertilizer products that quickly get used up by plants and deliver short term results. Below I detail the nutrient specific organic sources as well as the best broad spectrum organic sources.
Nutrient specific organic sources:
Organic sources of Nitrogen-Fish meal, blood meal, fish fertilizer, poultry manure pellets and aged chicken manure
Organic sources of Phosphorus-Bone Meal and Rock Phosphate
Organic sources of Potassium-Kelp Meal, Liquid Seaweed, Greensand, Granite Meal and Wood Ash
Magnesium-Epsom Salt, Dolomite Lime, Chelates and Borax
Calcium-Calcitic Lime, Dolomite Lime, Gypsum and Oyster Shells
Boron-Borax and compost. Boron becomes available as organic matter decomposes
Amendments with broad spectrum nutrients:
Broad spectrum amendments with the three primary nutrients of N,P,K and micronutrients in slightly lower nutrient quantities then the nutrient specific amendments above, include garden compost and aged manure.
Manure is rich in primary nutrients (N,P,K) and micronutrients such as Copper, Magnesium and Zinc as well as being a good source of organic matter to improve soil structure or act as surface mulch. Manure also adds microorganisms to the soil improving microbial diversity and biomass in soil.
Different types of aged manure and their best uses:
Cow and Steer manure are well balanced with nutrients in less concentrated form and are good for all round garden use. I use these in Rose beds and around other ornamental shrubs. This is an ingredient in the tri-blend manure (cow, chicken and mushroom from organic production facilities) I use in the veggie garden.
Cow, sheep and goat manure are also rich in beneficial microorganisms.
Chicken manure is higher in Nitrogen and unless from an organic producer, may contain higher levels of arsenic (added to non-organic chicken feed to control parasites). Non-organic sources should not be used in food growing gardens for this reason.
Mushroom manure is horse manure used in the commercial production of mushrooms. The mushrooms have extracted more nutrients from the manure so its often less nutrient-rich then other forms. Unless from organic production facility, it can contain significant pesticide residue so inquire if the product is from an organic producer before using in food gardens. It also contains Calcium which makes it more alkaline so its best used for alkaline loving plants and shouldn’t be used around acid-loving plants.
Compost provides trace amounts of N,P,K and macro-nutrients and micro-nutrients in lower doses then manure or the above nutrient specific amendments. Finished compost generally contains small amounts of the primary nutrients: usually 1-2% nitrogen, 0.6.-0.9% phosphorus and 0.2-0.5% potassium but this can vary depending upon the predominant material being composted. It also often contains low levels of secondary nutrients: Calcium, magnesium and sulfur.
Composts primary benefits are that it adds organic matter to improve soil structure and helps make nutrients more available to plants, helps the soil retain those nutrients for a longer period of time and also introduces beneficial soil micro-organisms to the garden that help suppress pathogens. It works well as a mulch to prevent surface evaporation and erosion on slopes.
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