Growing a garden successfully over several seasons can be a challenge, so its important to understand the science behind the earth your garden lives in. Soil science involves many formulaic components depending on varying environments, but the most common rule of thumb for improving your garden soil lies in a potent acronym: NPK (Nitrogen, Phosphorous, Potassium).
N for Nitrogen
Nitrogen helps the chlorophyll process of your plants, making them greener and helping them grow faster. Nitrogen is often depleted from soil when it is heavily cultivated, or if it is washed away by heavy rains, flooding or watering.
P for Phosphorus
Phosphorus helps your plants develop healthy and strong roots, fend off diseases, create abundant and sturdy blossoms, fruits and seeds.
K for Potassium (or Potash)
Potassium also aids root growth, disease resistance, and can be beneficial for drought resistance in drier climates.
All three of these nutrients can be found separately or in prepackaged ratios. To know exactly how to amend your soil for optimum growth results, make sure to test your soil first! Your garden soil may well have plenty of potassium and phosphorus, but be deficient in nitrogen, and too much of any one nutrient can be harmful to your plants.
Simple soil test kits will provide fairly accurate results, and will help determine the needs of your garden soil. You can also get a detailed soil analysis from a lab if that's necessary for your needs. The National Sustainable Agriculture Service has a list of labs that provide these services.
It is especially beneficial to understand the nutrient levels in your garden soil if you are starting a new garden, whether it be a raised bed garden or in the ground. This way you can ensure that your plants have the best chance of growing healthy roots, stalks, leaves, blossoms, and eventually fruits.
Always choose organic fertilizers! You can find fertilizers with all three nutrients included in different ratios, or you may choose to purchase each one separately. Good sources of potassium and phosphorus are wood ashes and fish fertilizer, while manures, seed meals, bone meal and blood meal are excellent sources of nitrogen.
Apply the powder or liquid to a freshly turned bed and water it well to let the nutrients soak in. Let the amended bed sit for at least a full day before planting seeds or transplanting seedlings. Then watch your garden grow!
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