People have been gardening in raised beds (simply gardens where the soil level is higher than the surrounding land) for centuries. If your gardening location
- has poor soil
- is difficult to till
- has limited space
- has low spots which pool water
- has pests (rodents, birds etc)
- or mobility is an issue
then maybe raised bed gardening is for you.
Why Raised Bed Gardening?
Studies have shown that gardeners can get more than twice the yield out of a raised bed garden versus a traditional garden. Why? Since you aren’t walking or driving a tractor over a raised bed, the soil doesn’t get compacted. Seeds and seedlings can be planted closer together since there is no need to leave space between the rows for walking, and their roots love the airy soil.
Improved Soil Condition
The soil is less compacted. Plus, since you are generally adding soil to a raised be (rather than tilling up whatever is there) you can make sure to choose a nice mix of compost, pH balanced soil and organic matter.
Ease of Working
Because you are walking around, not in, raised beds, they can be worked even when the weather is wet and the soil is muddy. Raised beds can be built as high as needed, so if bending is a problem, just build your bed to a comfortable height.
Ease of Pest Control
Raised beds are easier to cordon off from rodents and birds.
Drip irrigation or soaker hoses (both of which apply water directly to the soil and reduce evaporation) are perfectly suited to raised beds.
Build a Raised Bed
So you are sold on the idea of gardening in raised beds, but how do you build one? Of course, you could purchase a kit online or at a gardening store, but if you to choose to build your own, follow these easy instructions.
If possible, build a raised bed in the fall or winter when you have a break from other gardening projects. This will give your new soil time to settle and you can get rid of weeds with out resorting to chemical herbicides.
Decide what kind of plants you want to grow. Then look at the seed labels (or research online) to figure out how much sunlight those plants need. Choose a site that meets the sunlight needs of your future plants.
Here’s what those labels mean:
“Sun” means direct sunlight at least 8 hours a day.
“Shade” means less than 4 hours of direct sunlight.
“Partial Sun” means between 4 and 6 hours of sunlight a day.
- Choose a site with easy access to water.
- Select a place out of strong winds.
- If you are planting for aesthetics, make sure your beds can be easily seen from a window, porch or other perching location
- Don’t build your bed in standing water or in low areas where water drains. Plants to best in light, airy soil—not the waterlogged variety. If there aren’t any dry places to be found, consider lining your bed with plastic.
- Build beds so they slope about 2 percent (a 1/4 -inch drop per foot of horizontal distance) away from any structures, or away from the center of the bed.
- If necessary, install drain tiles or septic line tubing the length of the bed and through either end of the bed as a drainage channel.
- Choose a material to build your bed that fits your style and your budget. Raised beds can be made with stone, brick, wood or other materials found or bought.
- Use caution when selecting railroad ties or other treated materials. They can leach toxics into the soil, which is especially a problem in vegetable beds since you’ll be eating the plants.
- The planning stage is a good time to think about irrigation.
- Irrigation may be as simple as watering by hand. Make sure your bed is near a water source such as a faucet.
- Hand watering can be time consuming, so a drip irrigation system (build your own) or soaker hose may be appropriate. You’ll still need access to a faucet.
- Automatic sprinklers are an option, but since they water the leaves rather than directing water directly to the soil, disease and fungal growth can become a problem.
Lay Out the Perimeter
- Use stakes and string to mark the perimeter of straight-edged beds.
- For beds with curves lay a garden hose on the ground and play around until you get the shape you like.
- A bed should be narrow enough that you can reach the center to plant, weed and harvest.
Remove Existing Vegetation
- Cut and hand pull as much as possible.
- If your plot is littered with weeds (unwanted plants), and you have time, place a clear layer of plastic over the growing area and secure with rocks. After a couple months the heat generated should kill all plants.
- As a last resort, use an organic herbicide.
- Till the soil. Even if you are adding new soil, tilling the old soil now will make it easier for the two to mesh and deep roots to get through.
- Dig a shallow trench paralleling your perimeter. This way the bottom of the edging will be slightly recessed into the ground and stable.
- Lay your first layer of stone, brick etc. If your bed will be more than 12-18 inches it may need to be reinforced with rebar or set in concrete. (See Constructing a Raised Bed for instructions on building with specific materials.)
- Continue laying building material until bed is the height you desire.
- TIP: If building a tallish bed, it may be easier to start adding soil now. It can provide support for your edging.
- If you are installing a sprinkler system, now is the time to do it.
- Layer a good soil mix (it should hold water, but have good drainage) with compost until the bed is filled.
- Grade soil slightly away from the center of the bed and nearby structures.
- Let the soil settle for a week or two. You may need to add more now or next year.
Planting a Raised Bed
Planting in a raised bed isn’t very different than planting anywhere else in your yard.
- Plants that are adapted to the local climate and weather will be easier to maintain—and thrive better than non-adapted plants.
- Succession planting will help you avoid bare spots.
- Companion planting will reduce the need for pest and disease control.
- If you are planting vegetables, rotate them each year. Every plant requires different amounts of nutrients. By moving plants around the garden, the soil won’t get depleted in any one place.
- Bunch plants that have similar needs (water, nutrients, sunlight) together for ease of care.
- Perennials can be planted further from the edge since they require less care than annuals, which will need to be replaced each year.
- If the bed is only accessed from one side, plant taller plants toward the back and shorter plants toward the front.
Mulching benefits the garden in many ways:
- Reduces water evaporation
- Keeps plant roots cool in summer
- Suppresses the growth of weeds
- Reduces runoff
- Makes the garden more attractive
- As organic mulches break down they will add nutrients and improve structure in the soil.
After planting your bed:
- Apply 3-4 inches of mulch
- Taper the mulch away from the bases of plants (less toward the stem).
Read Mulching 101 here.
Maintaining a Raised Bed
Irrigate plants as needed, letting the top inch of soil dry out between waterings.
As mulch breaks down, blows away or otherwise disappears, keep adding it to a depth of 3-4 inches.
Side dress with compost or use another organic fertilizer to replace nutrients lost to hungry plants or leaching.
Young weeds are easier to pull than established ones, so keep up with frequent weed removal.
As perennials get older (or at the end of the growing season) they’ll need pruning to stay healthy and look their best.
The best part of gardening! Pick your vegetables and flowers while reaping the results of your hard work.