Garden soil is much more than simple dirt. If we take a close look at the makeup of our soil, we will find that garden soil is a mixture of mineral particles, organic material, moisture, living organisms, and chemical nutrients. One of the most critical factors in a soil’s ability to support life is its texture. Depending on the size of the soil particles, the texture can range from very porous and well draining to extremely dense and resistant to water movement. We refer to this dense soil as clay due to the fact that most of its mineral particles are very fine clays. Ideal soils for gardening are sometimes known as loamy soil,and it is a mixture of sand, clay, mineral particles, and most importantly, organic material. To truly understand the importance of soil, we have to take an even closer look at its ingredients.
Soil microbiology is the study of all microorganisms that exist in the soil, specifically the ways they function and affect soil properties. Our soils are teaming with life, serving as excellent hosts for the growth and development of plant life. In fact, there are more microbes in one teaspoon of soil than there are people and soil provides shelter for around one quarter to one-third of all living organisms on the planet. This collection of organisms consists of bacteria, fungi, and algae that serve important roles in the overall health of soils. Soil has its own ecosystem that hosts large numbers of micro-organisms. Biodiverse soils consist of organisms that increase soil fertility, convert nitrogen from the air so it can be absorbed by plant roots, and mineralize nutrients. The community of organisms in soils range from microscopic microbes to earthworms and ants, all serving important roles in soil health. To achieve the maximum benefit from our gardens, landscape beds, and lawns, it is essential to support these complex ecosystems in order to preserve and promote fertile soils.
Within just one handful of soil live around 100 million bacteria. These bacteria are largely responsible for the process of converting nitrogen in the air into compounds that can be absorbed by plant roots. Although not as commonly abundant as bacteria, fungi also assist with extremely important functions of soil health. While one of their main activities is decomposition of organic matter, fungi also aid water and nutrient cycling. Fungi are responsible for binding soil particles together and water filtration and water holding capacities. Just like fungi, earthworms also break down organic matter, such as dead leaves, and produce natural fertilizers. They too support soil fertility with the transportation of water throughout the soil, as well as air, by creating tunnels that allow the two to flow freely.
We receive requests from our customers daily during the planting season to check the pH of their soil, and frankly, the samples we see are either lifeless, almost baby powder fine and hard compact soil, or heavy chunks of wet clay soil. Neither of these are optimal for plant growth and will take a little effort to correct. One of the causes of soil failure is the over use of synthetic fertilizers. Fertilizers are of two types: organic, or natural, and inorganic, or synthetic. Organic fertilizers are naturally occurring substances and include biofertilizers, green manure, organic manure and compost. They slowly leach essential nutrients into the soil and improve its overall vitality with time. Synthetic fertilizers are man-made combinations of chemicals and inorganic substances. They typically combine nitrogen, phosphorus, potassium, calcium, magnesium and other elements in different ratios. Synthetic fertilizers, unlike their organic counterparts, immediately supply essential nutrients to soil. Agriculture has relied on the use of natural fertilizers; substances that increase the nutrient levels of soil; for most of human history. Synthetic fertilizers made an entrance at the end of the 19th century and paved the way for modern agricultural production. Their use increased crop yields and brought on an agricultural revolution, the likes of which the world had not seen before. Synthetic fertilizers continue to have far-reaching effects, both positive and negative, and are likely to remain a part of human life. Synthetic fertilizers supply consistent amounts of precise nutrients to the soil. They act on soil immediately — unlike organic fertilizers that need to break down before absorption. This immediate effect is especially beneficial to dying or severely malnourished plants. Synthetic fertilizers are easy to use andare readily available. Unfortunately, Synthetic fertilizers have long-term negative effects. Synthetic fertilizers kill beneficial microorganisms in the soil that convert organic material into nutrient-rich organic matter. With the microorganism population gone, plants become reliant solely on synthetic fertilizers and the soil becomes less and less hospitable to plant life. We see this more in lawns than anywhere else. Hard packed soil that resists digging with conventional tools like a shovel, yet when hit with a pick or digging bar, turns into a lifeless powder. This can be repaired. We can rebuild and replenish the natural biodiversity of this type of soil, the same way we convert heavy clay soil into a hospitable environment for our mid south landscape.
Clay soil is prevalent in many parts of the United States, and it can be a bit challenging if you are trying to grow a flower or vegetable garden. While some trees and shrubs grow well in clay, most annuals, perennials, and vegetables don’t have roots strong enough to force their way through dense clay. And if spring flower bulbs are your dream, forget it—most bulbs tend to rot over the winter in wet clay soils.Clay soils can be improved, however. With a little help from us, you can improve your clay soil and you’ll be able to grow most flowers and vegetables with a much greater level of success.
Clay soil is defined as soil that comprised of very fine mineral particles and not much organic material. The resulting soil is quite sticky since there is not much space between the mineral particles, and it does not drain well at all. If you have noticed that water tends to puddle on the ground rather than soak in, it is likely your ground consists of clay. Soil that consists of over 50 percent clay particles is referred to as “heavy clay.” But chances are, you probably already know if you have heavy clay if the soil sticks to your shoes and garden tools like glue or forms big clods that aren’t easy to separate.
Even clay soil has some good qualities. Clay, because of its density, retains moisture well. It also tends to be more nutrient-rich than other soil types containing high levels of minerals such as calcium, potassium, and magnesium
Improving clay soil or soil that has been depleted by over use of chemical fertilizers will take a bit of work, but the good news is that the work you do will instantly improve the structure of the soil and make it easier to work with. Most of the work is done up front, although some maintenance will be necessary to keep your soil at its peak.
It is best to improve an entire planting area all at once, rather than to attempt improving the soil in individual planting holes as you need them. In an existing bed, however, you can amend each planting hole with compost. Adding organic compost on the surface to the areas where you didn’t plant is just as important as adding it where you did. All of the nutrient content of the compost will leach into the ground, increasing and feeding the beneficial microbes in the soil. Overtime, by adding compost to your garden like you would add mulch, you will see a difference in plant health and productivity.
If you are adding a new landscape bed or starting a vegetable garden, to improve your soil, you’ll need to add 6 to 8 inches of organic matter to the entire bed. You can add any organic matter you can get your hands on. Grass clippings (as long as they haven’t been treated with chemicals), shredded leaves, rotted manure, and compost are all perfect choices. Spread your organic matter on top of the soil. Here’s where the manual labor comes in. The organic matter needs to be mixed into the top 6 to 12 inches of soil. Digging it in and mixing it with a shovel is a great way to do this, however, if digging is just too hard on your back, using a tiller is fine.
When you’re finished, your garden bed will be several inches higher than it was originally, but this is not a problem. Your garden bed will settle some over the course of a season as the organic material breaks down. The soil structure will continue to improve as microorganisms in the soil work to break down all of the organic matter you’ve added.
The bed can be planted immediately. Plan to add more organic matter in the form of compost once or twice a year. This will continue the process of improving the soil’s structure and offset any settling that happens.
Surprisingly often, people imagine that the proper way to improve a dense, clay soil is to add the opposite kind of mineral material….sand. After all, loamy soils, viewed as ideal garden soil, are a mixture of sand and clay. Unfortunately, when sand is added directly to clay, the result is something that more resembles concrete. The reason loamy soils are great for plants is they have a large ratio of organic material in them as a foundation for the sand and clay. Without lots of organic material, clay plus sand equals an awful garden. Clay soils are best improved primarily with the addition of compost and other organic materials.
After a season or so, it’s a good idea to collect a soil sample and have it tested to see if you have any nutrient deficiencies or pH issues. The report you get back will offer suggestions for how to improve the garden further. Add any organic fertilizers or soil amendments outlined in your report, and your bed will continue to be perfect for growing healthy plants for years to come.
Organic material will need to be continually added to prevent your garden from returning to its heavy clay state. Fortunately, this becomes a self-fulfilling process as garden plant material breaks down and works its way into the soil. Rather than cleaning your garden down to the soil line each fall, allow leaves and other plant material to decay naturally and become part of the ongoing ecosystem of a good garden soil. If your garden is occasionally mulched with more compost, there will be little additional work you need to do.
On lawns and large landscape areas, fertilizers like Milorganite provide an organic boost to microbe populations and are a great source of natural nitrogen and iron. Feeding with products like Fox Farm Microbrew or Kangaroots or any of the plant specific Espoma products will increase the microbe population in your soil. Natural Guard Soil Activator is a highly concentrated organic soil conditioner that provides humic acids that stimulate nutrient uptake and soil microbial life. Humic acid also promotes strong and healthy root development. In the mid south, it is a generally accepted practice to aerate our lawns once a year. The use of a machine that pulls up plugs rather than the use of solid spikes is preferred. Once the soil has opened up by aeration, this is a perfect time to spread a layer of compost over your lawn. Back to Nature Cotton Burr compost, Back to Nature Blend, or Back to Nature cow manure are perfect sources of the natural organic materials your lawn needs to be healthy and at its best. The periodic use of chemical fertilizers to give a quick boost to your landscape or lawn is okay. However, use products that are slow release and are specific to your needs.
No matter the condition, we can improve your soil and help you have a productive vegetable garden or landscaping that will be the envy of the neighborhood. It all truly begins with the soil.