Improving Soil on the Small Farm

Woman planting lemon balm in soil.
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One of the biggest components of growing healthy plants is the soil. It sounds simple, but many beginning farmers skimp on proper preparation of the soil before planting. With some testing, care, and amending, you too can have loamy, well-aerated, deliciously dark soil to grow the best crops.

Determine Your Soil Type

The soil is usually classified as clay, sandy or loamy.

  • Clay soils are rich in nutrients but tend to hold water.
  • Sandy soils are just what they sound like - quick-draining and high in sand.
  • Loam soils retain moisture without bogging down and are fluffy and full of air pockets and nutrients.

There are several ways to test your soil, but the easiest is to pick up a handful of moistened soil and squeeze it. Here is how different types of soil will react:

  • Loam will hold its shape, then crumble with a poke.
  • Clay will hold its shape even when poked.
  • Sand will not hold its shape and will fall apart when you open your hand.

It's also a good idea to have soil type and pH tested by your County Extension Office. They can also test your soil for various contaminants such as lead - important information to have before you use that soil to grow food.

Amend the Soil

Once you know what kind of soil you have, and if you have any pH issues or nutrient deficiencies, you can begin amending it.

  • Adjust pH. Proceed somewhat carefully here, as changing pH can be trickier than it initially seems. Give it time and retest your soil. Consider choosing crops that work with your existing soil pH. For acidic soil, you can add lime. For soil that's too alkaline, add sulfur or peat moss.
  • Add organic matter. Increasing the amount of organic matter is probably one of the most important things you can do to improve your soil no matter what its current type. Compost, animal manure, grass clippings, leaf mold, and green manures (cover crops) are all great organic matter to add. At least three inches of organic matter spread over the planting surface should be added - and four to six is better.
  • Adjust nutrients. Often, adding organic matter and giving it time will be enough to balance out the nutrient profile of your soil. But if your soil test showed great imbalances, you might consider adding blood meal for phosphorus, bone meal for calcium, and kelp or greensand for potassium deficiencies.

Plant Cover Crops

Cover crops, also called green manures, are a great way to improve soil aeration and texture, add nitrogen, as well as support and encourage microorganisms and worms.

Choose the proper cover crop for the season - for example, winter rye is a fall crop, while buckwheat is sensitive to frost. Grains such as oats or rye tend to add lots of organic matter to the soil, while legumes such as field peas or hairy vetch fix nitrogen. Sometimes farmers combine several cover crops - for example, a field peas/oats mix - to gain the benefits of each type of plant.