Building an inground flower bed enhances your property while adding a wealth of new gardening experiences. Whether you are digging your first inground bed or adding a new landscape detail, planning is the key to success, and there are several planning strategies to try before you begin digging your bed. As in the case of starting a new business, the three essential elements are: location, location, location. Figure out the best place for your new flower bed and enjoy the beautiful results.
Take some photographs of your house and yard, including the area where you want to put your new flower bed. This will help you determine the affects of the new bed on the overall look of your property. Since many of us tend to think about a flower bed from a single point of view--often how it looks from inside the house--photographs will enhance your overall vision.
Draw a plan of your new bed, noting dimensions. You need information about the size of your bed to calculate materials you will need. Again, point of view matters. You may find it useful to look at your proposed bed from several angles as you draw. Climbing a step ladder or viewing your yard from a second-story window gives you useful information for placement.
Identify the elements that you need for good growth and maintenance. Assess the amount of sunlight you will have when trees and other plantings are in full-leaf. Determine how easy it will be to water your new bed; you may find yourself adding more hose or a rain barrel to your shopping list.
Creating the Bed
Test your soil to determine what soil enhancements you will need. A soil-test kit measures the acidity or alkalinity of your soil. Most flowering annuals and perennials do best in neutral or slightly acidic soil (although there are plants with very specific needs), and you may need to add acidic or alkaline enrichments to produce the balance you need. Nurseries often carry small soil-test kits. Consult your County Extension Office for soil-testing equipment and results.
Dig several test-areas in your new bed to determine soil character and content. Especially in areas of new construction, you may find that you need to remove rocks and debris before going farther. Even under established lawn, subsoil may be inhospitable to garden growing. Only a thin layer of topsoil is needed to sustain grass. You may need to remove poor subsoil and replace it with high grade topsoil. Ideally, your new bed should contain good soil to a minimum depth of 12 inches.
Enrich existing or new topsoil with amendments that improve drainage and plant nutrition. Heavy clay soil may need sand or peat moss to lighten its weight and make it possible for plants to develop good root systems. All garden-bed soils benefit from regular additions of rotted leaf mold and other forms of compost. As a rough guide, calculate the soil volume using the dimensions from your plan and multiplying them by a factor of 12 inches (depth). Plan to add an equal volume of amendments when establishing a new bed.
Consider adding materials that improve weed control or drainage before filling your new bed with planting soil. Lining the bottom of your new bed with permeable landscape fabric or a 1/2 inch layer of newspapers make it harder for established weeds to trouble your new flowers. Creating a 2-4 inch layer of gravel at the bottom of your bed will improve drainage of standing water.
Dig in your soil amendments, mixing them with topsoil as you go. Break up heavy clods of existing soil with your shovel or rake and incorporate sand, peat and compost evenly. (This same mixing technique will make your overly sandy soil richer and more moisture-retentive.) Rake smooth and plant.