By Sally Cunningham
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Whatever you plan to grow, the soil makes or breaks plant health and crop success. New gardeners and homeowners, before they start designing and planting, must address the state of the soil. If you see an established landscape with healthy-looking woody plants (trees and shrubs), get information from prior residents what was done in the past. Your soil may be perfectly fine for now—but all soils become depleted. We must replace what we use. Good stewards of the soil take steps to add organic matter (which supports the community of microorganisms and provides nutrients for plants) on a regular basis, usually in the form of compost or a compost-enhanced soil mix.
Maintenance, if your soil is good:
Based on garden and landscape success, or testing, productive and well-textured soil will need a basic annual routine of soil care. On vegetable and flower garden soil, every year add a layer of compost (two inches) or compost-rich garden soil (such as Big Yellow Bag Garden Soil) to all exposed soil. (See lawn care instructions below.)
If you add compost in the fall: You may simply let it lie there, as it will enhance soil structure and nutrition as the worms and other organisms digest it. Many gardeners, including myself, cover the compost-layered soil through winter, to block weeds. This could be done with straw, cardboard, tarps, or heavy black plastic. Do not use wood chips in this situation because its decomposition often ties up soil nitrogen.) It is pleasing to find the soil ready for planting when you remove the covers.
If you add compost or garden soil mix in the spring: Be careful not to walk or use equipment on damp soil. When the soil crumbles, rather than cakes, in your hands—usually two or three weeks before planting, spread the compost or garden soil mix over the top of the exposed soil, and turn it over lightly. (If you till, make it one pass. If you dig by hand, leave the resulting soil coarse and crumbly. Over-tilling damages soil structure, and destroys the communities of healthy micro- and macro-organisms; it takes years to correct the damage.) On planting days, use a rake to loosen the soil surface, which disrupts small weeds and aerates compacted clumps.
How much Big Yellow Bag or compost to use?
In order to spread two inches of Big Yellow Bag garden soil across a raised bed, flower or vegetable garden, or landscape bed, use this formula based on the square feet you wish to cover:
3 x 6-foot bed (18 square feet): {SHOW VOLUME AND PORTION OF BYB?)
3 x 12-foot bed or wide row (36 square feet): “
10 x 10-foot garden (100 square feet, allowing for paths) (SHOW NUMBER OF BYBS?)
For mixed landscape areas, add estimated square footage and use the formulae above. Cover soil around trees and shrubs from 2 inches outside the crown (shrubs) and from 3 inches outside the trunk (trees) to the dripline or farthest branches of the woody plant. Never crowd plant crowns or trunks. You may choose to cover these areas on top of the compost shredded bark mulch for decorative and weed-blocking purposes. (Some prefer cocoa shells, or wood chips. Avoid gravel or rocks, since they compact the soil and add reflected heat.)
Soil repair – If your soil is unfamiliar or in bad shape, begin here:
Collect a sample to test for soil pH. This measurement of acidity/alkalinity is crucial for success, most critically for growing rhododendrons, blueberries, and potatoes (or any ericaceous plant. (They require a low pH—acidity—below 6.0 or 5) For instructions on soil sampling, see the Fact Sheet about this from www.erie.cce.cornell.edu. At that site, choose “soil” and you will see what to do for testing. (A careless soil sampling will not provide meaningful results.) Master Gardeners, through Cornell Cooperative Extension, provide soil testing at several locations during the season. In addition to pH testing, a complete soil analysis is wise for gardeners beginning in a new location, especially for those intending to start a farm, grow a crop, create a new landscape, or invest in a new lawn.
After the soil test, you or a certified landscape r can follow the test’s instructions to prepare the soil for optimum plant survival and health. Most frequently, soil test results indicate soil compaction (lack of organic matter) or lack of nutrients, both of which are improved by adding quality compost. (Do not mix sand into heavy, clay soil. It was a traditional “fix” before scientists convinced the industry that a better answer is organic matter such as compost.) Other frequent findings (high pH), common in Buffalo and “North towns” especially, will indicate the need for sulfur-based, soil-acidifying amendments.
When to replace soil? If you suspect that your soil is contaminated, as in former industrial or construction sites or from other chemical or pollution exposures, it may be necessary to remove that soil (to a depth of 2 feet) and replace it with a quality garden soil product. (We recommend Big Yellow Bag garden soil.) If you or a landscaper is purchasing “topsoil,” discuss its source and consider a soil analysis before major purchases. Some “topsoil” is sub-soil scraped from construction sites. It may be heavy clay, or it can be damaged, compacted, or weedy. Also, all composts are not alike, and some can introduce serious weed infestations.
The raised-bed alternative: Sometimes replacing the soil may be overwhelming or too expensive, in which case a gardener or homeowner might consider raised-bed gardening. Ignore the old soil, and build enclosed beds (as tall as you wish), making sure there is drainage. Fill the new beds with quality garden soil, or a compost mixed with quality topsoil.
Especially for food crops or herbs, garden in healthy, un-contaminated soil.
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Sally Cunningham is a horticulturist and former Master Gardener, through Cornell Cooperative Extension, and a CNLP (certified nursery/landscape professional) through the wNY Nursery and Landscape Association. She is author of Great Garden Companions (Rodale Books) on organic gardening, Buffalo-Style Gardens (St. Lynn’s Press), and has provided decades of garden writing through The Buffalo News. Buffalo Spree Magazine, and many Rodale Books and Yankee Publications.
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