Garden & Greenhouse


How to Build a Cedar Potting Bench

Posted October 13th, 2016 by Robin Nichols in

cedar-potting-benchThis bench is designed to be strong without complex joints. An experienced woodworker can complete this potting bench in a day. If you’re a beginner, allow two or three days.

You’ll need basic carpentry tools like a tape measure, large and small squares, and a chisel. You could make most of the cuts for this potting bench with a circular saw. However, a power miter box will ensure perfectly square end cuts, and a table saw is almost essential for cutting the grate slats. If you don’t have a table saw, ask a friend, neighbor or the staff at the lumberyard to cut the pieces for you. You’ll also need a drill with the bits mentioned in the story and a jigsaw.

Choose Straight, Nice-Looking Lumber

Use the Shopping List at the end of this article to buy your materials. Cedar is used for this bench, but pine is cheaper. Consider using pressure-treated pine if you’ll be leaving the bench outside. All of these are available at home centers and lumberyards. But make sure to pick straight boards with at least one nice-looking side. You can hide a few minor defects on the back or underside of the bench. Also, avoid boards with large knots, which will weaken key parts and make it harder to cut the notches.

When you get your materials home, cut the pieces to size using the Cutting List at the end of this article. Many of the parts, like the 1 x 1-in. slats for the grate and the 2-1/2 in. wide legs, have to be cut the length of the board. This operation, called ripping, is possible with a circular saw, but it’s much quicker, easier and more accurate with a table saw.

Make Tight-Fitting Joints for a Strong Potting Bench

Notching looks tricky, but it’s simple if you follow these key steps: First clamp each pair of legs together, and using dimensions from Fig. A, mark the lower edge of each notch. Use a square to draw lines across the boards at these marks. Then align the corresponding horizontal board with this line and mark along the opposite edge to get an exact width. Using the boards in this manner to mark the width of the notch is more accurate than measuring. When you saw the notch, cut to the waste side of the pencil line, leaving the line on the board. You can always enlarge the notch or plane the board to fit a notch that’s too tight, but you can’t shrink a notch that’s too wide. Tight-fitting joints strengthen the bench and look better too.

Assembly is Quick Once the Parts are Cut

Before you screw the horizontal pieces to the legs, pick the best-looking side of the boards and make sure it’s facing the front of the bench. Drill 5/32-inch clearance holes through the cross members to avoid splitting them. This will also allow the screws to draw the boards tight to the legs.

Use only one 1-1/4 in. screw to attach parts F and G to the front legs. Center the screw so it doesn’t interfere with the 3-in. screws you’ll be installing to secure the leg assembly. Use a 3/4-in. spacer block to align the cross members (E) before you drive in the 3-in. screws.

If you’ll be leaving your bench outdoors, use stainless steel screws or corrosion-resistant deck screws. For extra strength and durability, put a small dab of construction adhesive on each joint before you screw the pieces together. To hide the 3-in. screws that secure the front legs, use a 3/8-in. brad point drill bit to drill 1/4-in. deep recesses before you drill the 5/32-in. clearance holes. Then glue 3/8-in. wood buttons into the recesses after you screw the parts together.

Prepare Your Materials

Keep a framing square handy as you assemble the leg sections and bench frame and use it to make sure the assemblies are square before you tighten the screws.

This example uses a plastic wastebasket, but any container with a lip will work. Trace the shape on a piece of plywood and then cut the hole a little smaller so the plywood supports the lip. The bench top is made of 1-in. thick bullnose cedar decking. Join two pieces with cleats to make a removable cover for the dirt container. Glue 1 x 1-in. slats together with water-resistant wood glue to form the grate. Scrape off excess glue before it dries. Then allow the glue to dry overnight before you sand the grate and trim the ends flush. Screw cleats to the bottom of the grate to keep it positioned and allow easy removal.

The width of the end pieces (P) varies, depending on the dimensions of your decking. To determine the width, first center the grate, removable cover and three more boards on the bench top, leaving an equal space on each end. Then measure the distance from the last board to the outside edge of the back leg and cut and notch the end pieces to fit. Glue 3/8-in. wood plugs into 3/8-in. by 1/4-in. deep recesses to hide the screws that hold the two end pieces (P) and lower shelf boards in place. Sand them flush after the glue dries.

Complete the potting bench by notching the 1×8 shelves and securing them with 2-in. screws through the horizontal 1×4 shelf rails (H). Black metal shelf brackets were used to support the ends.

Protect Your Potting Bench With a Good Finish

Unfinished cedar has some resistance to decay, but the best strategy is to apply a top-quality exterior finish to keep the wood from cracking, splitting and rotting. Penetrating oil–type finishes with a small amount of pigment provide a natural look and reduce fading. Finishes that leave a film provide the best protection. Take extra precautions to seal the bottom of the legs to keep them from absorbing moisture from the damp ground. For interior use, any good-quality varnish will work.

Item QTY.
2×6 x 8′ cedar (rip to 2-1/2′ for legs) 1
2×4 x 6′ cedar (rip to 2-1/2′ for lower cross members) 1
2×4 x 4′ cedar 1
1×2 x 4′ cedar 3
1×3 x 8′ cedar 1
1×4 x 8′ cedar 2
1×8 x 4′ cedar 3
5/4 x 6 x 4′ bullnose cedar 9
2′ x 2′ 3/4′ plywood 1
1-1/4′ stainless steel screws 80
2′ stainless steel screws 50
3′ stainless steel screws 10
1-1/4′ finish nails 1 lb.
3/8′ wood screw plugs* 30
3/8′ wood button plugs* 10
10-oz. tube of construction adhesive 1
Water-resistant wood glue 1
6’x 8′ decorative shelf brackets 4
10’x 14′ x 18′ deep Rubbermaid wastebasket 1
14′ x 20′ x 4′ deep litter pan 1
100-grit sandpaper sheets 2

Cutting List

A 2 1-1/2′ x 2-1/2′ x 62′ (back legs)
B 2 1-1/2′ x 2-1/2′ x 33′ (front legs)
C 2 1-1/2′ x 2-1/2′ x 21′ (lower cross members)
D 1 1-1/2′ x 2-1/2′ x 21′ (middle cross member)
E 2 1-1/2′ x 3-1/2′ x 21′ (upper cross members)
F 2 3/4′ x 2-1/2′ x 47′ (lower rails)
G 1 3/4′ x 3-1/2′ x 47′ (upper rail)
H 2 3/4′ x 3-1/2′ x 47′ (shelf rails)
J 1 3/4′ x 7-1/4′ x 47′ (backsplash)
K 2 3/4′ x 7-1/4′ x 47′ (shelves)
L 1 3/4′ x 3-1/2′ x 42-1/2′ (bench-top support)
M 2 3/4′ x 1-1/2′ x 10-1/2′ (cover cleats)
N 2 3/4′ x 1-1/2′ x 12-1/2′ (grate cleats)
P 2 1′ x 5-1/2′ x 23′ (bench-top ends; cut to fit)
Q 5 1′ x 5-1/2′ x 23′ (bench top)
R 7 1′ x 1′ x 23-1/2′ (slats)
S 12 1′ x 1′ x 4′ (spacers)
T 2 3/4′ x 1-1/2′ x 25-1/2′ (container cleats)
U 2 3/4′ x 1-1/2′ x 16-3/4′ (bench-top cleats)
V 4 1′ x 5-1/2′ x 47′ (lower shelf)
W 1 12-3/4′ x 20-1/4′ x 3/4′ plywood (container support)

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