The single most valuable investment in your home landscape is soil improvement—healthy soil means healthy, productive, beautiful plants! Soil that is healthy is loose, nutritious (and thereby, fertile), well-drained, and has the ability to retain needed moisture and nutrients.
Growing healthy soil requires adding compost and other organic amendments. Compost is dark in color and nearly odorless. It is a mixture of decaying plant and animal wastes (living and dead organic material), which support a very intricate web of life teeming within soil. Other organic materials include shredded leaves, straw or grass clippings, arborist’s wood chips, and worm castings.
Poor soil has little organic matter, worms, or microbial activity. Ornamental plants attempting to live in such conditions are vulnerable to pests and disease and struggle for proper nutrition, while weeds often thrive! Alternatively, healthy soil is comprised of minerals, water, air, organic matter, worms, and billions of insects and microbes.
- Microbes are microscopic organisms such as bacteria, fungi, protozoa, and nematodes. Generally speaking, microbial activity decomposes soil ingredients and converts them to nutrients usable by plants. Soil-dwelling fungus and bacteria also assist plants with disease resistance and drought tolerance, and can utilize resources that are normally out of reach from the plant’s root system.
- Worms also have an invaluable role in growing healthy soil. They eat organic matter as they tunnel through the soil, endlessly searching for food. As they tunnel, they leave behind “castings” or excrement. Tunneling aerates (ventilates) soil, improving drainage capacity and texture. Deposited castings are comprised of bacteria, nitrogen, magnesium, and phosphorous—all vital components of the soil web.
Active, healthy soil is a place where plants are anchored. Furthermore, their roots gain access to the essentials: oxygen, water, and nutrients that have settled in the pockets of air between mineral and organic particles. Fourteen of the seventeen nutrients mandatory for plant development and health are obtained in soil. The remaining three (carbon, oxygen, and hydrogen) are delivered via air and water.
Perform a home soil test to check levels of nitrogen, phosphorous, and potassium, as well as pH level; doing a fall test allows time for potential amendments to be effective by spring. A more substantial test can be done through a local laboratory; information can be found on the OSU Extension Service website: How do I test my garden soil?
Benefits of Healthy Soil
- Healthy, productive plants!
- A healthier ecosystem within your yard
- Plants that have greatly increased resistance to pests and diseases
- Less work in the garden (weeding, watering, tending to sick plants)
- A lower water bill: soil is able to efficiently use supplemental water; less water runoff due to the soil’s storage ability
- Increase in overall water quality of streams and rivers, resulting from decreased runoff from garden beds and reduced watering
Things That Can Damage Soil
Chemicals: Whenever possible, use organic products and always read the label.
Overwatering: Too much water prevents air from reaching plant roots and increases chances of disease and/or root rot. Overwatering also kills off a lot of beneficial soil microbes.
Over-fertilizing: Too much fertilizer actually causes stress to plants and synthetic fertilizers can cause salts to build up in the soil. We recommend slow-release, organic products such as G&B Organics. Think of this as feeding your soil and thereby, feeding your plants. It is best to only fertilize plants that need it or when indicated by a soil test.
Compaction: Soil particles that are tightly bound together do not drain well and can make it difficult for roots to grow. Compaction from heavy machinery, wood piles, above-ground pools, or even regular foot traffic are conditions that create soil compaction. Compacted soil needs to be aerated with the possible addition of organic material to vary the particle size.
What You Can Do to Grow Healthy Soil
Add compost: Products such as G&B Soil Building Conditioner, G&B Harvest Supreme, Malibu Compost, and G&B Worm-Gro make simple work of soil amendment. Making your own compost is far less daunting than it may seem!
Mulch: Add a thick layer of aged bark, arborist’s wood chips (www.getchipdrop.com), grass clippings (no weeds or seeds), leaves, etc. on top of the soil to reduce evaporation of water, prevent weed growth, and insulate plants. Over time, organic mulch breaks down to improve soil structure. Allow your fall leaves to remain in the landscape and flower beds or rake into your vegetable garden area as mulch (large leaves may be shredded or mowed for smaller bits).
Plant a cover crop in beds or areas of beds that are currently unused. Not only can cover crops help suppress weeds, they also often fix nitrogen (legumes), add organic matter, improve soil texture, decrease run off (soil absorbs water more readily), and suppress soil pests and diseases. After planting cover crops, they are cut down and gently turned under the soil 2 to 3 weeks before planting the following spring.
Avoid compacting soil by not walking in your garden beds (this includes pets, too!). Instead, add stepping stones or paths for easier access. Ideal size for raised beds is no wider then 4 feet so it can be reached from both sides and never walked on.
Minimize tilling (including the use of rototillers). Remember, there is an extremely intricate web of life in every bit of garden soil. Optimally, in order for microbes, worms, and other soil critters to live productively and healthfully, they (like us) need their home to remain as undisturbed as possible. Deep tilling or turning of soil often unintentionally brings dormant weed seeds to the surface where they quickly sprout in your freshly prepared bed! Amendments can be layered on top of the soil or gently worked in with a gardening fork or cultivator. Worms and soil microbes will also help incorporate the layers into the existing soil (lasagna gardening).
Rotate crops: When growing vegetables in your garden, rotate the areas in which they are grown. Different nutrients are taken out of the soil by different plants, so switching a crop’s location will yield healthier soil and plants, as well as more productive crops! Various soil-born pests and pathogens may also be discouraged by annual crop rotation. Example of basic rotation: fruit (tomato, pea, squash, etc.), flower (broccoli/cauliflower, Brussel’s sprout, etc.), root (carrot, radish, etc.), shoot (lettuce, spinach, etc.)