To clear existing vegetation from garden sites, you should use one of two methods. The process you prefer will probably be based on how much time you have and how much effort you want to invest, and the kind of vegetation you’re removing.
If you’re handling turf or a ground cover, physical removal will work adequately. For a planting bed laced with noxious weeds, you’ll need an aggressive stance to eradicate them.
Regardless you’re going to want to start by defining the bed edge before beginning. Use a sharp spade to slice into vegetation. With the blade embedded into the soil, move the spade around to form an open trench. If you use herbicide to remove vegetation, create a physical barrier or shield using cardboard, plastic, or lumber to prevent any spray from drifting onto surrounding plants.
The Two Methods
Physically Remove Vegetation. Removing plants by hand involves exhaustive labor but provides a low-cost approach to clearing a bed. When clearing vegetation by hand, remove as little soil as possible; the top few inches of land is the most fertile. As you start removing the first pieces of existing vegetation, examine the ground beneath. You shouldn’t see any grass rhizomes, plant roots, or rooted stems. If you do, dig a little deeper and remove more soil.
When working with ground cover that roots along stems, search around in the proposed garden site and locate crowns of the plant. Focus on digging those out; the remaining stems should pull up quickly.
Herbicide. Herbicide exterminates weeds and turf in short order, killing the aboveground portion of plants, roots, or both. It’s an excellent choice when time is short. Read the package label; typically you can plant in an herbicide-treated area within 10–14 days. One of the most commonly used herbicides for killing grass and weeds is glyphosate.
Excellent use for herbicides is on a slope. Spray plant tops with herbicide and roots will remain to hold soil in place. When greenery dies down, you can dig through the remaining roots to plant.
If you need to wipe out weedy roots, spray plants in late fall when carbohydrates are moving from leaves into roots. At this time, herbicides move more readily into roots, and you should be free of problem weeds come spring.
Mix in Amendments
Once you have eliminated existing vegetation, it’s time to work amendments into the soil. This task is the most labor-intensive aspect of planting a garden. The goal in working the ground is to improve drainage on lower levels, if needed, and to work organic matter into the upper 6–8 inches of soil.
As you blend in amendments, try to create gradual changes in the soil from top to bottom. Work in amendments from the top down, aiming to increase organic matter in the topmost layer, where the majority of soil organisms and plant feeder roots are. Lower soil layers might need only to be broken up to enhance drainage. Before digging, make sure soil isn’t overly wet or dry.
Mix in amendments by hand, using a digging fork or round-point spade. Hand-digging makes sense in a small garden or to save money. Going over the ground two or three times with a shovel will effectively blend amendments into the soil. For a large garden, rent or borrow a rototiller. A tiller isn’t useful in rocky ground or a bed filled with tree roots, but it works fast in sandy or loamy soil. In clay soils, don’t churn the same area of the earth too much to avoid compacting lower layers where digging tines strike.
In soil with many tree roots, a digging fork (also called a spading fork) maneuvers well without damaging roots. A digging fork also makes quick work of soil preparation in sandy soil.
To mix in amendments, add a 1- to 2-inch layer of organic matter on top of the soil and work it into the top 6–8 inches. If digging by hand, use a digging fork to turn forkfuls of dirt on its side, mixing in the amendments as you turn the soil.