Build your raised bed in four main steps: choose a location, assemble the frame, fill it with soil, and plant

A raised bed is a wooden or composite box you fill with soil and plant into. You build it by stacking boards into a rectangle, securing the corners, placing it where it will get sun, and filling it with a mix of soil and compost. Most people can build one in an afternoon with basic tools. The whole project costs between $50 and $200 depending on the size and materials you choose.

The real work is not the building—it is choosing the right spot and getting the soil depth right for what you want to grow. A bed that sits in shade will produce less than one in sun. A bed that is too shallow will stunt root vegetables. This guide walks you through each decision so your bed works for years.

Key Takeaways

  • Raised beds need at least six hours of direct sun per day for most vegetables, and eight hours is better.
  • Standard boards are 2 inches thick and 8 or 10 inches tall; you can stack two boards to go deeper for root crops.
  • Cedar and composite materials last longer than untreated pine, which rots in three to five years.
  • Fill your bed with a mix of topsoil and compost rather than garden soil alone, which compacts and drains poorly.
  • You can build and plant a raised bed in one day, but the soil will settle over the first month and you may need to add more.

Pick a location with enough sun and level ground

Most vegetables need six to eight hours of direct sun per day. Walk around your yard in the morning and afternoon to see which spots stay sunny. Avoid areas under trees or next to buildings that cast shadows. If your yard is mostly shaded, leafy greens like lettuce and spinach will still grow in four to six hours of sun, but tomatoes and peppers will not.

The ground should be as level as possible. A bed on a slope will drain unevenly—one end will stay wet and the other will dry out fast. If your yard slopes, you can dig out the high side and use that soil to build up the low side, or you can accept that one end will need more water. Do not build on a slope steeper than a few inches over the length of the bed.

Check for underground utilities before you dig. Call 811 or your local utility locating service and they will mark gas, electric, and water lines for free. This takes a few days, so plan ahead.

Choose your frame materials and size

The most common raised bed is made from two 2-by-10 boards (which are actually 1.5 inches thick and 9.25 inches tall) joined at the corners to make a rectangle. A 4-by-8-foot bed is a standard size that fits most yards and is large enough to grow a real harvest without being so big that you cannot reach the center. A 4-by-4-foot bed works for smaller spaces. Do not go wider than 4 feet in either direction or you will have trouble reaching plants in the middle.

Cedar and composite materials last the longest. Cedar is naturally rot-resistant and will last ten to fifteen years. Composite boards made from wood fiber and plastic last even longer—often twenty years or more—but cost two to three times as much as cedar. Untreated pine is the cheapest option but will rot in three to five years, especially if it sits in wet soil. Do not use pressure-treated lumber made before 2004; older versions contained arsenic. Newer pressure-treated wood is safe but will still rot eventually.

You will also need four corner brackets or L-brackets (metal pieces that hold the boards together at the corners), a drill or screwdriver, and wood screws. Galvanized or stainless steel screws will not rust. Buy 3-inch screws; use two or three per corner.

Assemble the frame on level ground

Lay your boards out in a rectangle on the ground where you want the bed to sit. If the ground is not level, dig out high spots or add soil to low spots until the boards sit flat. This matters because an unlevel bed will have one end deeper than the other, and water will pool on the low end.

Attach the boards at the corners using your brackets and screws. If you are using L-brackets, position them on the inside of the frame so they do not stick out. Drill pilot holes (small starter holes) before driving screws; this keeps the wood from splitting. Tighten all screws firmly so the corners do not shift when you fill the bed with soil.

If you want a deeper bed for root crops like carrots or potatoes, stack two boards on top of each other at each side. Use longer screws (4 inches) to hold the stacked boards together, and use brackets at both the bottom and middle joints.

Fill the bed with soil and compost

Do not fill your bed with garden soil alone. Garden soil compacts when wet and drains poorly. Instead, use a mix of about 60 percent topsoil and 40 percent compost. Topsoil is the dark, nutrient-rich layer from the top of the ground; compost is decomposed plant material. Both are sold by the bag or by the cubic yard at garden centers and landscape supply yards.

To figure out how much you need, measure the length, width, and depth of your bed in feet, multiply them together, and divide by 27. That gives you the number of cubic yards. A 4-by-8-foot bed that is 10 inches deep needs about 1 cubic yard of soil mix. Most garden centers will deliver soil for a fee if you order more than a few cubic yards.

Dump the soil and compost into the bed and mix it together with a shovel. Fill it to the top; the soil will settle over the first few weeks and you may need to add more. Water the bed thoroughly after filling so the soil settles and compacts.

Plant or sow seeds right away or wait for the season

You can plant when ready after filling the bed. If you are planting seedlings (small plants from a nursery), dig a hole, set the plant in, and firm the soil around it. If you are sowing seeds, follow the depth and spacing on the seed packet. Water gently so you do not wash the seeds away.

If you are building in fall or winter and want to plant in spring, cover the bed with a tarp or landscape fabric to keep weeds from growing in. You can also leave it uncovered; weeds will grow but you can pull them out before planting.

Maintain your bed through the seasons

Add a 2-inch layer of compost on top of the soil each spring. This replaces the organic matter that breaks down over the year and keeps the soil rich. You do not need to dig it in; just spread it on top and water it down.

Water deeply and regularly, especially in hot weather. Raised beds dry out faster than in-ground gardens because water drains through the bottom. Stick your finger 2 inches into the soil; if it feels dry, water. Most vegetables need about 1 inch of water per week, either from rain or from you.

At the end of the season, pull out dead plants and add them to a compost pile if you have one, or throw them away. Do not leave them in the bed; they can harbor pests and disease. You can leave the bed empty over winter or plant a cover crop like clover to add nitrogen back to the soil.

Frequently Asked Questions

Can I put a raised bed directly on grass?

Yes, but the grass will eventually grow up through the bottom and into your soil. Lay cardboard or landscape fabric on the grass first, then set the bed on top. The cardboard will break down over a year or two, but by then the grass underneath will be dead and the roots will have rotted away.

How deep does a raised bed need to be?

Most vegetables need 8 to 10 inches of soil. Leafy greens like lettuce can grow in 6 inches. Root crops like carrots, beets, and potatoes need 12 inches or more. If you are growing a mix, build it 10 to 12 inches deep so everything has room.

What if my raised bed is in partial shade?

Leafy greens, herbs, and root crops will grow in four to six hours of sun. Tomatoes, peppers, and squash need eight hours or more. If you have four to six hours, stick to greens and herbs. If you have six to eight hours, you can grow most things but yields will be lower than in full sun.

Do I need to replace the soil every year?

No. Add 2 inches of compost each spring to replace what breaks down, and the soil will stay healthy for years. After five to ten years, depending on how much you harvest and how much compost you add, you may want to replace the top few inches if it feels depleted.

Can I build a raised bed without tools?

You need at least a drill or screwdriver to assemble the frame. If you do not have either, ask a neighbor or friend to help, or buy pre-made raised bed kits that snap together without screws. Some garden centers also offer assembly services for a fee.