Raised Beds

Raised bed gardening is a method that uses a variety of materials to frame an area, elevating the garden soil from 12" to 36” above the surrounding soil. Raised beds tend to be more productive and easier to manage. One exciting new example of raised beds is keyhole gardens.

Benefits of raised bed gardening

Raised beds in the garden make it easier to control soil structure, irrigation, and pests. Raised beds also allow you to plant earlier because the soil warms up more quickly. Generally, plants in raised beds are planted more closely together, creating a beneficial microclimate that suppresses weed growth and retains moisture. Since gardeners do not walk on raised beds, soil compaction is avoided, and they make reaching plants (and weeds) much easier! Raised beds are an excellent choice in limited spaces, or if you are a renter and not allowed to alter the landscape. Another added benefit of using raised beds is that it is very easy to add trellising, row covers and protective wire to keep birds away from seedlings.

Netted or screened panels help keep pests out of raised beds

How to build raised beds

Raised beds can be practically any size or shape. A raised bed can be nothing more than a walled area on the ground or it can be an elaborate artistic structure that showcases garden gems, or anything in between! You can see an excellent sampling of different types of raised beds at instructables.com. The steps below can help you get started creating your very own raised bed.

1. Select a location

• How much space is available?
• How much sun exposure will plants receive?

2. Select building materials

• Purchased wood can provide certain benefits. Cedar and redwood have natural insect- and rot- resistant properties, but they cost more. Pine is less expensive, but it won’t last as long.
• Composite wood, made from recycled plastic and wood fibers, is extremely durable.
• Repurposed pallets and other scrounged materials can make excellent raised beds, just be sure to avoid painted, stained, or pressure-treated wood, because the chemicals they contain may be absorbed by plants. Check the codes on pallets to see which chemicals have been sprayed on them.
• Bricks, blocks and stones are inexpensive and durable. The small spaces in cinder blocks can also be used as planting holes.
• Straw bales may not last long, but they are inexpensive and, as they decompose, add nutrients to the soil.
• Large tree branches and logs can also be used to frame a raised bed.

3. Clear the area

• For raised beds that sit on the ground, remove any existing weed and, level the ground, Some people cover the area with newspaper or cardboard, but this interferes with water and gas exchanges and will attract termites and voles. Landscape cloth also causes problems.
• If moles or ground squirrels are a problem, create a base made from hardware cloth to protect plant roots. (Chicken wire does not work.)

4. Measure twice, cut once

• Once the site is cleared, measure the area for the raised bed.
• Calculate the materials needed to build the raised bed, taking corners into account.
• Most raised beds are 10” deep, but 6” is deep enough for most crops.
• Determine your method of joining the corners. You can use brackets, wood fasteners, or scrap wood.

5. Add soil

• Soil quality determines how well plants grow. Invest in the highest quality potting soil you can afford for your raised bed. If your budget it tight, you can contact local municipalities for discount priced or free compost.
• To calculate how much soil a raised bed will need, multiply length times width times soil depth. For example, the soil needed for a 4’ x 8’ raised bed that is one foot deep is determined by multiplying 4 x 8 x 1, which gives us 32 cubic feet. [To calculate cubic yards, divide this number by 27. Soil sold by the cubic yard is usually cheaper, but you'll need a truck.]
• Compost should be added at least once a year, to replace the nutrients that have been absorbed by plants. 

Plants for raised bed gardening

Raised beds are a great tool for productive foodscaping, since the root systems of most vegetable crops are relatively shallow. If your raised bed is on the ground, however, it won’t matter. Even the worst soil is bound to improve over time, with a raised bed above it, to allow deeper-rooted plants to perform well. If ground squirrels and voles are a problem in your area, attached hardware cloth, not chicken wire, to the bottom of your raised bed. This will protect your plants' roots. 

The first rule of vegetable gardening is to plant what will grow where you are. Email me you zip code and I will send you a planting chart for your zone.