Soil Fertility and the Magic of Compost

By Cynthia Averett, VINES Urban Farm Manager
03/12/21

Your garden soil is more than just dirt; it contains all the food your plants need to grow. Just like people, your plants need a balanced, healthy diet; they need water, nutrients, minerals, and even living things like worms and bacteria. Some of the nutrients that plants need to grow are nitrogen, phosphorus, and potassium, and some other things like calcium, magnesium, and sulfur.

These “plant foods” are too small to see, but there are many ways to tell if your soil is healthy. You could pay for soil tests, but you can also tell the health of your soil just by looking at it! Healthy soil should be dark in color, should break apart and crumble in your hands, and should be full of worms and other bugs. In both of the pictures below, the soil on the right is much healthier than the soil on the left.

Plants will take nutrients from the soil as they grow, and over time you will need to add some of these nutrients back in. One of the best ways to do this is with compost. Compost is organic material that has decomposed (broken down) over time, and is full of the nutrients and living things that your plants need. Many farmers call compost “black gold”, it’s that important! Compost can be made from animal manure, food scraps (except for meat, dairy, and oil), leaves, lawn clippings, wood chips, and anything that used to be alive. Make sure to avoid using “raw manure”, which is manure that hasn’t been broken down yet. Raw manure is too “hot”, which means it contains too many nutrients, especially nitrogen, and it can hurt your plants.

You can buy compost from garden stores or farms, and you can even make your own compost at home. To learn more about composting at home, check out this list of resources from Cornell Cooperative Extension.

To use compost in your garden, add 1 or 2 inches to your entire garden before planting in the spring. You can gently mix it in with the soil, or leave it right on top and let the worms and microbes do the work! You can also add compost in the fall when your garden is done, and whenever you are going to replant.