How to build a cheap raised bed from fence pickets

Build it

1. Cut the dog-ear off the top of each picket with a square cut, so all six are 70 inches long. Cut two of them in half: four end pieces of 34¾ inches.
2. Cut the 2 × 2 into six posts, 11 inches long: the height of two pickets.
3. Lay two long pickets edge to edge on a flat floor, the better faces down. Screw a post across both at each end, set in ⅝ inch from the ends (a scrap of picket makes the spacer), and one in the middle, the post tops flush with the top edge. Drive two screws through each picket into each post. Build the second long side the same way.
4. Stand the two long sides up, posts inside, 34¾ inches apart. Fit two end pieces between them at each end, flush with the ends of the long pickets, and screw them to the corner posts, two screws each. Measure both diagonals: each should be about 6 ft 6¾ in. Push the corners until they match.
5. Choose a sunny spot, loosen or clear the ground under the bed (the site guide shows how) and set the bed level on it.
6. If gophers or voles dig in your garden, staple hardware cloth across the bottom before the soil goes in. UC IPM advises hardware cloth or ¾-inch mesh poultry wire under raised beds for gophers; Colorado State University Extension gives ¼-inch hardware cloth for voles and pocket gophers.
7. Fill the bed 10 inches deep.

How much soil it takes

Filled 10 inches deep, an inch under the top, the inside takes 13.7 cubic feet of soil: 10 bags of 1.5 cubic feet, or about half a cubic yard in bulk. The posts are taken out. Ten inches is the least the University of Georgia Extension gives for most garden crops; where the ground under the bed is poor, loosen it so the roots can go deeper.

Open this bed in the soil calculator to change the depth or split the soil into a mix.

Reaching the middle

The bed is 3 feet wide, so the middle is 18 inches from either long side: within reach from both sides for most adults. Against a fence the far side is nearly 3 feet away; the width guide shows how to measure your own reach. For a bed you work from one side, cut the end pieces 22¾ inches instead: the bed is 2 ft wide outside, still takes six pickets, and holds 6 bags at the same depth.

Which pickets to buy

University of Maryland Extension, citing the USDA Forest Products Laboratory, names cedar and redwood among the decay-resistant woods to build a vegetable bed with, and says to avoid old wood treatments: CCA, creosote and penta-treated lumber. The pressure-treated wood most widely sold for homes today uses micronized copper azole, which it calls low in toxicity; Oregon State University research it cites found copper rose only within an inch of the bed’s edge and not in the plants grown in it.

Fence pickets are also sold in pressure-treated pine. If you would rather keep treated wood away from your soil, buy cedar, or line the inside of the walls with heavy plastic, as the same page suggests. Pickets are ⅝ inch thick against 1½ inches for a 2 × 6, so even cedar ones will not last as long as a bed of thicker boards.

What this plan does not cover

This is a plan for a small, low bed on open ground. Pickets are thin: the University of Georgia Extension asks for a vertical support about every 4 feet on boards 1 inch thick, and this bed has one every 3 feet; a longer bed needs the same, and a taller one thicker boards, as in the tall bed plan. It is not an engineered design and makes no load rating. For a bed on a patio or deck, read the hard-surface guide first.

References

• Raised Garden Bed Dimensions (Circular 1027-4), University of Georgia Cooperative Extension.
• The Safety of Materials Used for Building Raised Beds, University of Maryland Extension.
• Pocket Gophers (Pest Notes), UC Statewide IPM Program.
• Vegetable Gardening in the Mountains, Colorado State University Extension.