Nothing is more important to the success of any garden than the quality of the soil. Rarely is the soil in your yard ideal for growing flowers or vegetables without some amendments or improvements. In almost every situation, the best thing a gardener can do is add organic matter. Adding it just once won’t be enough. Try to add some kind of organic matter at least two or three times each year.
But what is ‘organic matter’?
Organic matter is any of a variety of materials derived from plant tissue. Fallen leaves, grass clippings, shredded bark, sawdust, peat moss, hay and straw, even manure, are all considered organic matter. With manure it’s the plant-based diet the animals eat that makes it organic matter. Compost is the classic source, which makes sense since it is made from any of the above ingredients.
Organic matter is eaten by earthworms and converted by soil microorganisms into nutrients for your plants and into humus for the soil, making any type of soil more ideal for root growth. Heavy clay soil is lightened up by organic matter so that excess water can drain through and plant roots can expand easily. Sandy soil benefits from organic matter because it becomes more like a sponge, able to hold on to some nutrients and water, but allowing the excess to drain away.
The more organic matter in your soil, no matter what type it is, the larger the population of earthworms and micro-organisms will be. Don’t worry about having too much organic matter, that is nearly impossible!
There are many ways to provide organic matter. If you employ a few of these methods every year, you will see a dramatic improvement in your soil quality and plant performance.
Cover crops, such as oats, winter rye and ryegrass, are planted in the fall to cover the bare ground over winter. When the cover crops are tilled under in spring they add organic matter.
Green manures are plants that are tilled into the soil while still green. Their green tissue contributes nitrogen and well as lots of organic matter. Oats and rye work well as green manures and buckwheat is excellent as long as it is planted during the warm summer months and tilled under before it sets seed.
Natural mulches not only contribute organic matter as they break down, but also do an excellent job of conserving soil moisture, controlling weeds and cooling the soil. Grass clippings make an excellent mulch as long as they are applied in a layer no more than 2-3 inches thick and have not been treated with weed killer. Straw works well in vegetable gardens but is too coarse for most flower gardens. Hay is all right, but it will bring in more weed seeds than will straw. Fallen leaves that have been chopped up by the lawn mower are excellent and turn into marvelous leaf mold. Sawdust and fine bark chips are all right, but they take up nitrogen as they decompose, so you will need to supply extra nitrogen, either with manure, blood meal or conventional fertilizers.
As you harvest and clean up your garden either compost all the scraps and debris or spread them over the ground and till them into the soil before planting a cover crop.
In new gardens, set aside one section in which you will only grow a series of green manure crops this year. Next year, plant vegetables in this section and designate a new section for the green manure series. Or, after harvesting a short season crop such as lettuce, scatter oats over the former lettuce row, let them grow during the summer heat, then till them under and plant a fall crop of spinach there.
Extension offices can test soil pH, and soil samples can be sent to Cornell University for a complete nutrient analysis. But these tests only give you readings. In almost every case, additional organic matter will help. Once you get in the habit, it just won’t feel “right” to have any bare, unused soil in your gardens. Your plants will respond with larger root systems, greater production ,and increased resilience and tolerance to pests and environmental stresses.
Photo courtesy Scott Bauer, USDA NRCS.