Written by Susan Seawolf Hayes with guidance from Daniel Woodham, Goat Lady CSA Farm Manager
The Home Gardener Series, Part 3 of 4.
Soil. It’s the basis for our garden. It makes all the difference in how fruitful your garden is and affects the amount of time needed to keep your garden in shape.
The right soil offers a hospitable environment for plants in a blend of air, water, and nutrients. But the ideal balance of ingredients eludes most gardeners. Even those who are fortunate enough to start with good soil must contribute to its improvement regularly because soil is a living layer of earth that changes naturally with time and the weather.
REASONS TO AMEND YOUR SOIL
Is your pH out of ideal range? The term “pH” refers to the degree of acidity vs. alkalinity in your soil and measures the amount of lime (calcium) in your soil, and the type of soil you have. Moist climates tend to have acidic soil (pH lower than 7.0), and dry climates, alkaline soil (pH higher than 7.0). Although some plants are very sensitive to pH, most plants in your vegetable garden will thrive with a pH range of 5.5-6.8.
Your local county extension office will test your soil for you at no charge. We can’t tell you how important this step is so don’t skip it—unless you are opting for a raised bed that you fill with “perfect” soil in the first place.
Do you have heavy, wet soil? Unimproved soil in the Piedmont of North Carolina is generally red clay, (see “Introduction to the Soils of North Carolina,) especially if it has been cleared for a home site. Clay holds moisture far better than sandy soil, which tends to compact the soil, making it so heavy that plants (particularly young ones) can literally smother. So one good reason to amend your soil is to lighten it up, making it more friable (crumbly) so that it drains well and gives room for plant roots to grow.
How are your microorganisms? Unimproved soil generally is poor in microorganisms–most of which were removed when the topsoil was moved to prepare the homesite.
How is your nutrient supply? Organic gardening feeds the soil, whereas chemical gardening feeds only the plants, leaving the soil even more depleted than it was at the beginning of the season. Adding proper soil amendments each year will keep your soil in optimum shape at gardening time.
SPECIFIC AMENDMENTS TO CONSIDER FOR YOUR SOIL
Lime. Before applying any lime to your soil, you should test your soil’s pH. (Again, test your soil via the county extension office or many garden supply shops sell inexpensive pH test kits.)
You, of course, will be looking for a pH in that ideal 5.5-6.8 range. If it is, you’re ready to consider your other soil amendments. If your soil is seriously out of optimum pH range, the best way to change pH is slowly, over the course of several years.
If the pH is low, add hydrated lime as follows to raise soil alkalinity: to increase pH by 1 point, add 12 ounces of lime per square yard of clay soil. (Test your soil each spring, particularly if, during the year, you have added hardwood ash or bone meal to your soil during the year, since these substances also raise pH.) It is best not to overdo lime, since a little goes a long way. If your pH is seriously low, you may want to adjust it gradually over 2-3 years, with some lime added in the spring and additional hardwood ash, bone meal, crushed oyster shell or crushed marble added during winter.
If the pH is high, (not common for central NC), you may raise soil acidity by adding sulfur. To reduce the pH 10 points, thoroughly mix 3.6 oz of ground rock sulfur into each square yard of soil before planting. Or you might try a mixture of the following, added any time during the year: sawdust, composted leaves, wood chips, leaf mold, and especially peat moss. If the pH is quite high, consider building a raised bed and filling it with nursery topsoil.
Finished compost/peat moss and load of topsoil/bags of potting soil. Compost is simply decayed organic matter. If you live on a wooded lot, chances are you have a ready supply of compost under your trees. The composting process begins as soon as the leaves fall in autumn and continues ad infinitum. Or you may have started your own compost pile, adding layers of grass clippings, topsoil, shredded black-and-white newspapers, vegetable scraps, etc., and turning the pile occasionally. Remember not to add meat or dairy scraps, and try to avoid plants that might reseed all over your garden (unless you want them!). Good finished compost is usually quite black, crumbly and has an earthy smell with no funkiness. Mix compost or peat moss (which is a kind of compost that has decomposed for many years in peat bogs) half and half with bags of potting soil (pricey) or a load of topsoil from the garden center.
YOU’RE READY TO BEGIN
If you are starting a (red clay) garden for the first time and are not using raised beds, till your soil with the amendments from the above selection. You can certainly just use a garden spade to turn the soil and incorporate the amendments if you don’t have a tiller or if you just love physical labor. If you are using raised beds, hallelujah! Fill new beds with that topsoil/compost mix plus other amendments, or top up old beds with the same.
Don’t forget to place taller plants and/or trellises at the back of the garden so as not to shut out the light from shorter plants. For seeds, plant at height suggested on package, add a little soil and tamp lightly with the flat of your hand to make sure seeds contact the soil. Tiny seeds (such as carrots) may just need a thin sifting of soil over them, but you may need to mist them regularly until the seeds sprout (using too much water can wash them right out of the ground). If you choose to use starter plants instead of seeds, put an additional handful of compost or peat moss.
Do keep seeds and newly planted starter plants lightly moist (no drowning), and sit back and watch your garden grow!
WATCH FOR OUR NEXT INSTALLMENT: What to Plant When.