Gravel boards are a quick and easy way to create informal raised beds of almost any shape. This will help you to overcome problems such as poor soil and bad drainage and allow you to sow, plant, care, harvest and cut both crops and flowers without trampling on the soil. Boards may also be used to enclose an existing bed.

Make a plan of your design before you start work; a number of symmetrically arranged beds may be appropriate for herb and vegetable gardens, whilst borders and flower gardens may suit asymmetrically arranged straight or curved edged beds.

Materials

• Gravel boards: (15 cm depth) or pressure treated timber planks 2.5 cm x 15 cm.
• Stakes: 4x4 cm or 5x5 cm treated timber, 45-60 cm in length, and preferably pointed at one end. You will need enough to use at 1 m intervals around the beds, more for a curved design.
• Annular nails: 5-7.5 cm - allow two per stake.

Method

1. Rake the site roughly before you start and remove large stones and clods of soil.
2. Mark out the beds using pegs and string.
3. At one corner of the bed, drive a stake into the soil so that 15 cm is left above ground. The stakes should be long enough so that at least 25 cm of their length is buried. Note that the stakes should be positioned at the back of the edging.
4. Position the remaining corner stakes.
5. Insert the rest of the stakes, spacing them evenly between the corner posts. They should be set approximately 1 m apart, although this will vary slightly depending on the length of your beds. Use a spirit level to ensure that their tops are level.
6. Position a heavy object, such as a head of a sledgehammer or a concrete block behind the first post. This will help to keep it secure whilst you drive the nails home on the first board.
7. Hold the first board in position against the first corner peg and nail it to the post at the top and the bottom. Try to use 5-7.5 cm annular nails as their barbed shaft will resist any levering pressures.
8. Move the concrete block or other object you are using to support the stakes to the next post. Making sure that the board is level, nail it to the stake at the top and the bottom. Continue around the length of the bed.

Creating Curves

If you are creating a curved edge, you will need to set the stakes closer together - tight curves may require a distance of only 30 cm between posts. Cut shallow notches along the back of the board (no more than half its depth) at intervals of about 2.5 cm to help it to bend and reduce the risk of splitting the timber. Gently bend the board around the curve, adding in more posts where necessary.

Joining Two Boards

Two pieces of board may be joined in one of the following ways.

Bracing

A short length of board (30 cm) may be used to brace the two pieces. Nail the brace piece to the back of the two boards to join them together. Use two nails to fix the braced boards to the post; one at the top on one side of the join, and one at the bottom on the other side.

Mitre Join

When joining two boards on straight runs, you can use a mitre cut. Cut each plank at a 60° (one from the bottom sloping to the left, the other from the top, sloping right). Hold the boards together, making sure that the stake is positioned in the centre of the join. Use four nails to fix the boards; two above and below the join in a slightly staggered line.

Double Staking

If you need to join two boards at a point where the bed changes direction or is on a curve, you will need to use the double staking method. Drive in two stakes, about 5 cm or so apart so that they will each support one of the ends of the boards. Take care when driving in the second stake to prevent it dislodging the first.