Which soil is best for plant growth? As a beginning gardener, I plopped untold seeds, slips, and starts into the ground with no real way to tell whether they would grow or not. Finally, I learned that the soil I threw them into made a huge difference in survival and growth. Soil quality is important for other reasons, too; appropriate soil can help your plant resist diseases like powdery mildew or pests, as well as reduce your reliance on fertilizer.
It is important to realize that the appropriate soil for one plant might not be the ideal soil for another. Pumpkins, for instance, really prefer overly rich soil, even hills of pure compost. Rosemary, on the other hand, likes a sandy, well-drained spot that mimics its’ Mediterranean home as much as possible. Hydrangeas like loamy soils, but the pH often needs to be amended. Live oak trees do fine in a clay soil as long as they get enough water, but another species might have difficulty getting roots to break through the clay. So which soil is best for plant growth? The one that works best for that plant.
Generally, most home gardening environments have a layer of topsoil over your actual soil, thanks to years of the idea that every home should have a grassy yard. Dig down about a foot if you can to test soil and get a better idea of what you’re looking at. You can use home test kits, or in some places you can get free soil testing from the county extension office. I know this sounds strange if you’re not planning on commercial farming, but you can only tell so much by looking at or feeling the soil. Sure, you can determine whether you have sandy, loamy, or clay soil by looking – but pH can be just as important for some plants. Your extension agent also has a wealth of general agricultural information, and may even know of local gardeners or gardening clubs that can be helpful. Or, find someone friendly in your neighborhood who gardens, walk up and ask “What type of soil is best for plant growth?” if you can’t think of anything else.
Soil amendments include compost, peat, humus, manure, sawdust, potash, bloodmeal, sand, and many other items. Most gardening centers, and even some larger home centers, carry a variety of soil amendments ready to mix in. Some water treatment plants also offer sterilized waste compost for free or a nominal charge; if you use this, though, be sure that it is only used on decorative plants and never on anything which might be consumed. Though sterilized, it’s still better to be safe than sorry. Most loamy soils will only require some nutritive amendment, like adding compost, for most plants to grow well. Harder loam soils or those which are partly clay may need sand, peat, or vermiculite to allow better drainage. Sandy soils often require heavy organic material, for instance adding manure and humus.
Occasionally, you may discover that you have hardpack clay or something else which is not easily amended. Depending on tree distribution, erosion, and other factors, you might find that part of your yard is fine for planting but part of it has very poor soil. Raised beds are the quick solution, since you fill them with whatever sort of soil you need for your planting. I have also known gardeners to make “sunken beds” by digging out a large trench area and filling to yard level with their preferred mixture. Container gardening is another option, but has challenges all its’ own. So, when asking yourself “Which soil is best for plant growth?” you first need to examine the plant species, your growing zone, and the location you’ll be growing the plant in.