As you’re planning and plotting your garden for this spring, there are plenty of factors that you must consider. What plants will you grow? Where will you plant them? What will your harvest be like?
However, keep in mind that many of the answers to these questions–as well as the final outcome of your gardening efforts–don’t necessarily depend on you, but on the type of soil that your homestead possesses. Soil type can have a major impact on which plants thrive, and which ones die. Make sure you know which type of soil you have before you begin to plant this April.
Soil type is a multi-faceted concept, with dozens of factors that must be taken into consideration. When you think about your soil type, you need to consider its structure (is it clay, loam, sand, etc), which determines the porosity of its particles and how well nutrients, water, and oxygen will reach your plants.
You also need to consider your soil’s texture and color, as well as its nutrient content. Nutrient content contains several sub-categories. While most people think of nitrogen, phosphorous, and potassium as the only nutrients a garden needs, the reality is that there are dozens of micro- and secondary nutrients needed by developing plants as well.
Finally, you must also consider your garden’s pH. This is often influenced by, and in turn influences, the soil’s nutrient content and structure. It also affects the level of microorganisms in your soil, as well as how efficiently your soil responds to external stressors.
Soil is a living organism, and therefore, evaluating and modifying your soil type is not a simple process. However, with a bit of understanding of how soils work and are comprised, you can learn your soil type and alter it to suit any gardening needs with just a few years of patient, consistent work.
Clay soil feels lumpy and sticky when wet, but rock-hard when dry. This is the type of soil you might see cracking under the hot summer sun, as it has poor ventilation and few spaces for air or water to move through. It warms slowly in spring and is heavy to cultivate. Along with poor drainage, these factors make clay soil incredibly difficult to work with.
However, if drainage is improved or moisture content is moderated–such as through the use of heavy mulches–clay soil works well, as it tends to retain more nutrients than other types of soil.
Sandy soil drains much better than clay soil, and warms up more quickly in the spring. Although it is easy to cultivate, it often lacks nutrients, as they are easily washed out in wet weather. It also dries out quickly. Sandy soil will feel loose and gritty to the touch.
Sandy soil’s main problem in cultivating crops is that water drains too quickly, rapidly disappearing before the roots of your plants can reach it. This is especially true for seedlings with shallow, undeveloped roots. Erosion and runoff tend to be more of a problem.
Silty soil is more fertile than sandy soil and easier to cultivate than clay. Because it is heavier and denser than sandy soil, it also retains moisture and nutrients better than sand, without the sludge-like conditions of clay. However, the structure is weak and easily compacted, so working silty soil too early in the season can sometimes be damaging.
Silty soil tends to be cold and drains poorly. It can be easily compacted and poorly aerated, causing issues, in particular, with root crops like carrots and beets.
Peaty soil is somewhat rare, as it contains a high percentage of organic matter–also known as peat. This soil inhibits decomposition, meaning there are fewer nutrients, but it works well for plant growth if fertilizer is added. It retains water easily and, like clay, may require extra help with proper drainage. It warms up quickly in the spring and is exceptionally dark in color.
Peat soil, once drained, provides a good growing medium for most plants. It can become overly dry in the summer months, and in some cases, can cause fires. However, it usually holds water well, retaining in the drier months and protecting the roots from damage during wet months. It often works as a good amendment to other types of soil.
This type of soil is also relatively rare, and is an alkaline soil with a pH of over 7.5. It typically contains a high volume of rocks and often is found over chalk or limestone bedrock. Due to its nature, it tends to be higher in some minerals but makes some inaccessible to plants, such as manganese and iron. This can inhibit growth and cause leaves to yellow, but can be countered by adding fertilizers.
Clay is like the Goldilocks of soil–if too wet, it becomes heavy and prone to damage. If too dry, it can be hard and compact, making it difficult to turn. Although clay tends to hold the most nutrients, it needs a lot of care to be tillable.
The final type of soil, loam, is considered by most homesteaders to be the “perfect” type of soil. It has good, solid structure, and is packed with nutrients. It is easy to cultivate, warming quickly in the spring and retaining moisture throughout the hot summer months. It can both retain moisture and drain easily, making it the golden ticket of all types of soils. Loam has a higher pH and calcium levels as it is higher in organic matter.
In addition to the specific soil type, you also need to pay attention to the acidity of your soil, which we have mentioned briefly already. pH goes hand in hand with soil type and structure. pH usually ranges between 3.5 (very acidic) to 8.5 (very alkaline). A pH of 7 indicates a neutral pH. In general, fruits and vegetables prefer soil to be neutral or very slightly acidic.
That being said, if you have more alkaline soil, that doesn’t mean you can’t garden. There are some plants that actually prefer a less acidic soil, so if you are having trouble working with your soil type, consider changing your planting strategy.
pH also influences how well certain nutrients break down in the soil and are made available to plants. For example, at a pH of 6 to 7.5, microorganisms are the most active, working hard to break down organic matter and supply nutrients to plants’ roots. That being said, different diseases and pests also prefer a wide range of soil pH, so knowing your soil’s levels can help you stay on guard for particular problems.
You can estimate your soil’s pH by looking at what your garden grows best. Plants like rhododendrons thrive in acidic soil, while plants like clematis grow well in more alkaline soils.
How Do I Tell What Type of Soil I Have?
In most cases, you can determine your type of soil by reading the descriptions above and taking a look–and feel–at your garden. Pick a handful up. If it feels slimy and sticky and retains its shape after you let go, you have clay soil. If it feels gritty or lumpy, it is probably sand. If it feels spongy, it is peaty soil, and if it feels smooth and retains it shape for a moderate amount of type, it is loam.
Another technique you can use to determine your soil type is the watering test. Sprinkle a small amount of water on the bare dirt and see how quickly it disappears. If it lingers for quite some time, it is probably clay, but if it disappears quickly, you likely have sandy or silty soil.
You can also try adding a small amount of soil to a glass jar. Fill the jar with water, stir, and let it rest for two hours. If you have sandy soil, the particles will sink and form a layer on the bottom, leaving the water fairly clear.
If the water is cloudy and the particles take a while to settle, you have clay. If you notice several layers of white, gritty fragments or that the water has taken on a gray hue, you have chalk. Peaty soil results in lots of particles floating, cloudy water, and small amounts of sediment on the bottom, while loamy soil will send the finest particles to the top and result in a clear water with layered sedimentation.
What is a Soil Test Kit?
Along with the informal, DIY methods of testing your soil, there are several more advanced and accurate ways to test your soil type as well. Formal soil test kits come in a myriad of formats, but some of the most common ones you might find are those that test the nutrient content of your soil. While soil structure (for example, whether it is clay, peat, or sand) is important to figure out when planning your garden, nutrient content is equally important and is a direct influence of soil structure – and vice versa.
Professional testing can be conducted by local county cooperative extensions. In some areas, you may have to contact the county extension agent to find the exact person who does the soil testing, as it might not be done in-house. In most cases, the process is simple.
You will need to pick up a free soil-sampling kit first. These are often available at public locations like office buildings or the local library, but you can also find them online for a small price. This kit will include a box for the soil as well as an informational form that you will need to complete. The form will ask you questions like what kinds of plants you intend to grow as well as when any amendments (like lime) were added. This will help the agent obtain a better understanding of the organic composition of your soil.
When you get home, you will need to scoop out some soil about four inches down in the ground. Into the sampling box it will go, but make sure you scoop out any unwanted matter, like sticks, debris, or even worms. Then, you’ll mail the box and a check (for usually less than $20) to the lab. In a few weeks to months, they will send you back the results of your test.
If having somebody else do the dirty work isn’t exactly your style, you can also test your soil yourself. DIY soil test kits can be purchased at local hardware stores or garden centers. These range in price, with inexpensive options starting around $7 with more elaborate kits pricing all the way up into the double-digits.
There are several types of DIY kits that are popular on the market. A pH meter will require you to stick a probe into the soil, which will send the registered pH back to a display screen. You could also purchase a pH soil tester which requires you to mix soil with water and pour it into a plastic container. You will then add a premixed powder and shake it before comparing the color to an accompanying, pH-correlated color scale.
Finally, the third type of soil test kit has additional capsules so that you not only discover the pH of your soil, but also what levels of nutrients it contains. This is especially beneficial if you are interested in testing for things like nitrogen, potash, and phosphorus so that you know what kind (if any) of fertilizer to add. Some labs won’t test for nitrogen because it leaches easily from the soil, but if you are interested in learning that information, this test kit is the way to go.
What About the Other Aspects of My Soil?
We already mentioned how you can test for certain nutrients and other factors in your soil. Key nutrients in soil include nitrogen, phosphorus, and potassium.
Nitrogen is required by plants to build proteins, with deficient plants producing yellowing leaves and experiencing stunted growth. Phosphorous is necessary for the development of root and seed systems, as well as many other natural processes. If your garden plants have a reddish or purplish pigmentation, phosphorous deficiency might be to blame.
Finally, potassium helps regulate water usage and disease resistance, as well as to produce strong stems and cells. Potassium can create poor root systems and cause your plants’ growth to slow to a halt.
While these are the key primary nutrients in your soil, there are countless other secondary nutrients and micronutrients. When people think about fertilizing their gardens, they often forget these lesser nutrients, but they are still integral to creating a healthy garden. These include calcium, magnesium, sulfur, iron, manganese, boron, zinc, copper, chlorine, nickel, cobalt, and molybdenum.
When you think about these nutrients in context, a store-bought chemical fertilizer might not do the trick. While chemical fertilizers provide concentrated, evenly measured levels of nitrogen, potassium, and phosphorous, they usually do not provide secondary or micro- nutrients. All are required for a healthy garden, as are beneficial microorganisms, which is why an organic fertilizer often works better.
Soil is more than lifeless matter – it is a living, breathing system. Healthy soil will contain high levels of the aforementioned nutrients (levels of which can be impacted by your soil type and acidity, by the way), and also active organisms like earthworms, insects, and microorganisms. Microorganisms in particular are incredibly important, as these creatures help to break don the remains of plants and other soil-dwelling organisms, releasing vital nutrients as they do so.
Healthy soil will also possess other characteristics, some of which you have a bit of control over. Others may be tougher to moderate. For example, healthy soil will have good water infiltration. If you have a naturally dense soil type, like clay, this might be an issue. It will have low rates of erosion, which you can combat by adding additional organic matter. Adding organic matter (like compost) can also help moderate your pH, add nutrients, and increase biological diversity in the soil.
What are Soil Microorganisms?
Living organisms in the soil, consisting of both plants and animals, are vital for soil health. Soil that has been overworked generally has lower quantities of microorganisms, but these agents are so important for maintaining soil fertility and productivity. Soil microbes help to cycle nutrients and also add levels of vitamins and enzymes that create healthy food.
Microorganisms can be broken down into several categories. Microflora are more commonly and broadly (but incorrectly) referred to as soil bacteria, and include organisms like fungi, mold, yeast, mushrooms, algae, actinomycetes, Streptomyces, and, yes, bacteria. Bacteria can be broken down further into autotrophic and heterotrophic.
Macroflora organisms are simpler to categorize, and are simply the roots of plants. These are an active part of the soil system, working to absorb and release nutrients as they grow. Microfauna in the soil include protozoa and nematodes, typically invisible to the naked eye, as well as larger macrofauna. Macrofauna are easier to detect and include animals like ants, moles, and earthworms.
What Do I Do If My Soil Is Not Compatible?
When it comes down to it, don’t treat your soil like dirt. Remember that soil biology is about so much more than its porosity, acidity, and base nutrient content. You need to think of your soil as a living, breathing creature that needs to be fed. Creating healthy soil does not happen overnight but is instead a constant, slow-moving process in which you must consistently work to improve the ground beneath you.
Adding organic matter and incorporating a no-till system of agriculture is one of the best ways to improve your soil structure and nutrient content. Many gardeners make the mistake of constantly tilling or turning their soil – particularly with motorized equipment – which is detrimental for several reasons. Constantly moving your soil kills microorganisms and causes soil compaction – a big problem in particular if you have heavy, clay soil. This makes it more difficult for oxygen, water, and nutrients to penetrate, and can ruin your garden’s overall success.
Dig as deep as you can, and incorporate broken down organic matter into soil. You might consider adding compost for nutrients, manure for extra nitrogen, or, for exceptionally sodden clay soils, add some horticultural grit or sharp sand.
Avoid tilling whenever possible. Instead of turning the soil to prepare it for the upcoming season and to get rid of weeds, consider planting a fall cover crop. This will help fix nitrogen back into the soil, improve your soil structure, and also control weeds well into the spring. Maximize the benefits of organic fertilizers, like compost, which not only fertilize your soil but also add some structure so that erosion, run-off, and nutrient and microorganism depletion are not problems you need to be concerned with.
Having perfect, loamy soil is incredibly rare. Luckily, there is much that you can do to improve the quality of your soil, or even change its type over time. Within a few years of diligent work, you will have luscious, fertile soil that can be worked for decades to come.