How to tell what your garden is made of.
Garden writers, including your humble correspondent, frequently make reference to good garden loam, rich with humus and teeming with beneficial creatures, with a colour and consistency like rich chocolate cake. Makes it sound good enough to eat, doesn't it? If our soils are that good, we should have titanic tomatoes, colossal columbines, and peas the size of Howard Dill's Atlantic Giant pumpkins, right?
Well…. let's face it, friends. Most of us don't have perfect garden soil, especially when we're starting out. A lot of soil throughout Atlantic Canada is sparse, with more rocks than soil; look at parts of Newfoundland and Labrador, where gardens are planted along roadsides, and native plants cling to whispers of soil on top of boulders and in niches between rocks of all sizes. And areas where there is plenty of soil often have clay, which turns to goo when it's wet and to hardtack when it's dry; some are plagued with soil so sandy that water runs through it like sugar through a sieve. And to top it all off, most of us have soil that is ranging on the acidic side of the pH scale, which can be a problem for many garden plants. What is a gardener to do?
The first thing, of course, is to panic not, regardless of what sort of garden you have or are contemplating, or what sort of soil you have. There are surefire fix-its for most soil problems, but first, we have to know just what we are dealing with for soil. Time for a little soil chemistry.
Soil is made up of a marvelous mixture of particles of various minerals, living soil organisms (fungi, algae, insects, and other small creatures), and decaying plant and animal organic matter. The final component of this mix is pore space, which is the space between the various particles through which water, air and plant roots are able to move. Mineral particles can vary in size from barely perceptible (clay) to easily visible (sand). The finer the particle, the less pore space available for air, water and root movement.
Good garden loam is composed of a mixture of all three particle sizes, along with ample organic matter to provide nutrients for plant roots to absorb, so those giant pumpkins can flourish.
Trouble arises when soil has too much sand, so that pore space is large and soils drain quickly of water and nutrients. Too much clay, with fine particles clumping tightly together, makes drainage and root penetration difficult.
To determine if your soil leans toward sand or clay, the Mason jar test for major soil components is easy and can be fun for children to help with. Scoop a trowel or two of soil from your garden plot and put it in a Mason or quart jar; fill the jar with water, cover and shake vigourously for a few minutes, then let stand overnight. Soil particles will settle out with sand on the bottom, silt in the middle, and clay in the top layer. Measure the depth of each layer; a good soil mixture will contain roughly the same proportion of each type of particle.
Another quick visual test is to take a handful of moist, but not soggy, soil and squeeze it into a ball. If it refuses to form a ball, it's sandy soil; if it gloms into a sticky mess, it's clay, but if it crumbles like that rich chocolate cake, you have good garden soil.
If you don't have the right stuff, don't despair. The cure for both excess sand or clay soil is to add organic matter to the soil. This means incorporating such material as animal manure, grass or leaf clippings, sawdust or shredded bark, seaweed, or any of a number of other options. What you add depends on what's easily available, but the most effective way to add organic matter is as compost, or rotted organic material.
You get the organic matter into the soil in several ways. If you have a vegetable garden or are planting a new bed, dig or rototill your compost, manure or other organic matter into the existing soil to a depth of a foot or more. If you have ornamental borders or beds that are already planted, add organic material around the plants and either let it break down into the soil gradually or scratch it in lightly with a hand trowel to mix it into the surface. However, this method takes a long time to improve soil more than a few inches deep. A more effective method is to use plenty of organic material when you're adding new plants: dig the planting hole deeper and wider than usually recommended and add a few inches of organic matter before planting the perennial or shrub. Backfill in around the plant with a mixture of the soil you dug up and more organic material, and finish off with a top dressing of compost or with mulch.
Many nurseries and landscaping professionals will recommend that you have a thorough soil analysis done. This is a fee-based service, where a private lab or government extension office will put soil samples through a variety of tests for particle composition, acidity, and the presence of specific minerals. The lab will provide a printout of results and usually a recommendation for adding fertilizers or other amendments such as lime. Although some gardeners may balk at paying for an analysis, such tests will likely save you money in the long run by providing recommendations for appropriate fertilizer applications or other corrections. Your garden will thank you.