Soil: A Brief Overview
The single most valuable investment in your home landscape is soil improvement—healthy soil means healthy, productive, beautiful plants! Healthy soil is loose, nutritious (fertile), well-drained, and has the ability to retain necessary moisture and nutrients.
Poor soil has little organic matter, worms, or microbial activity. Ornamental plants attempting to live in such conditions are vulnerable to pests and disease, whereas weeds THRIVE! Often, the condition of the soil can be assessed by what is or isn’t growing well there. For example, a lot of moss may indicate that the soil is acidic in pH, has low fertility, and is compacted (all conditions that moss prefers).
Alternatively, healthy soil is comprised of minerals, water, air, organic matter, worms, and billions of microbes (there are more living organisms in a handful of healthy soil than there are humans on earth). Microbes are microscopic organisms such as bacteria, fungi, protozoa, and nematodes, most of which are beneficial or benign to plants. Generally speaking, microbial activity decomposes organic matter and converts it to nutrients usable by plants.
Worms and arthropods both play important roles in growing healthy soil. Worms 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. Adding worm castings as an organic amendment is also a great way to improve soils.
Active, healthy soil is a place where plants are anchored. Furthermore, their roots gain access to the essentials such as oxygen, water, and nutrients that have settled in the pockets of air between mineral and organic particles. Fourteen of the seventeen primary nutrients needed for plant development and health are obtained from soil; the remaining three (carbon, oxygen, and hydrogen) are delivered via air and water.
Benefits of Healthy Soil
- Healthy productive plants!
- Larger crop yield (i.e. food)
- Curb appeal and increased real estate value
- More of the plants you do want and less of those you don’t (weeds)
- Healthier ecosystem within your yard
- Plants gain increased resistance to pests and diseases
- Less work in the garden (weeding, watering, tending to sick plants)
- Lower water bill—soil can efficiently use supplemental water you provide; less water runoff due to soil’s storage ability
- Increase in overall water quality in streams and rivers, resulting from decreased runoff from garden beds
Things That Can Damage Soil
Chemicals: Whenever possible, use organic products and follow package directions. Prevent problems rather than attempt to “fix” them.
Overwatering: Not only does too much water prevent air from reaching plant roots, it also increases chances of disease affliction.
Over-fertilizing: Too much fertilizer actually causes stress to plants. Use slow-release, organic products such as G&B fertilizers. Think of this as feeding your soil and thereby feeding your plants.
Compaction: Soil particles that are tightly bound together suffocate the delicate soil web of life. Consequently, plants are unable to obtain optimal nutrients or grow healthy, deep roots. Heavy construction equipment, seasonal pools, and even moderate foot traffic can cause soil compaction.
What You Can Do to Grow Healthy Soil
Add compost: Growing healthy soil is as simple as adding compost and other organic amendments. Compost is dark in color and is nearly odorless. It is a mixture of decaying plant and animal wastes (living and dead organic material) that support an intricate web of life teeming within soil. Products such as G&B Soil Building Conditioner, Harvest Supreme, or Malibu Compost make it easy to amend your soil right out of a bag. Making your own compost is far less daunting than it may seem, but it takes some time. Ask one of our experts for information on starting a compost pile if you are interested in giving it a try.
Mulch: Add a thick layer of arborist’s wood chips, aged bark, dried grass clippings, shredded leaves, etc. on top of the soil to reduce evaporation of water, prevent weed growth, and insulate plants. Over time, organic mulch breaks down and becomes part of the soil structure.
Plant a cover crop in beds (or areas of beds) that are currently unused. Not only do cover crops suppress weeds, they also fix nitrogen, add organic matter, improve soil texture, decrease run off (soil absorbs water more readily), and suppress soil pests and diseases. Cover crops are tilled or turned into the soil and allowed to decompose about 2-3 weeks before spring planting.
Avoid compacting soil by not walking in your garden beds (this includes pets, too). Instead, add stepping stones or paths for easier access.
Minimize tilling (including the use of rototillers): Remember, there is an extremely intricate web of life in every bit of garden soil. 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. To loosen soils without damaging structure, use a cultivator fork instead of a shovel or spade.
Rotate crops: When growing vegetables in your garden, rotate the area 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, plus more productive crops!
Local Testing Labs
A&L Laboratories (Beaverton): www.al-labs-west.com