DIY Potting Bench

Few tools are as valuable to a gardener as a potting bench.

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Andrew Weidman
Avoid aches and pains by customizing the height of the bench to what’s comfortable for you.

To a gardener, the potting bench is an indispensable tool. It provides a dedicated work space for seeding flats, starting transplants, repotting seedlings, bench grafting, trimming harvested vegetables, washing harvested vegetables… the list goes on and on. If asked their favorite tool, a gardener might pick a certain trowel or pruner, but they probably use their potting bench more, and for more diverse tasks, than any other tool they own.

There are plenty of potting benches available to purchase; some have shelves and bins for potting mix. Others have built-in wells to contain repotting messes, or frames to hold grow lights over seedlings. None ever seem to have all of the features you want, or the space you need. And you get what you pay for; cheap models rarely last more than a year.

However, for the price of a box of decking screws, a few brass fittings, a few 2-by-4s, a few hours of work, and some opportunistic upcycling, you can build the ultimate potting bench complete with every feature you want, including the kitchen sink. This project revolves around a salvaged section of kitchen countertop and a sink basin with faucet plumbing.

The countertop I used for this article came from our kitchen remodel. Even if you have no plans for updating your kitchen in the near future, you can still get your hands on a castoff sink counter. Once in a while, one will appear on the side of the road along with a “FREE” sign. Ask around; family, friends, or coworkers may be planning a remodel soon. Keep an eye on online crowd-sourcing platforms. The simplest and fastest way to find an old countertop and sink, however, is to go right to the source: call local contractors and ask them. Since contractors have to pay to dispose of construction waste, someone is certain to be happy to supply you with what you need. They may even have several to choose from.

A word on materials: The countertop will most likely be laminated particleboard or plywood. While lamination will protect the surface from water, exposed edges can swell and degrade if they get wet. Seal them with an aerosol rubberizing spray, especially if the bench will spend significant time outside in the elements.

The sink will probably be either stainless steel or enameled steel, and may be a single or double basin. Either style will work well and last for years. Stainless steel is considerably lighter, which will matter only during construction.

Speaking of weight, while finding a granite or quartz countertop is highly unlikely, if you should find one, be aware that it will be exceedingly heavy — too heavy to safely use.

Because of the variable nature of upcycling and repurposing a countertop, the following guidelines will contain few hard measurements. Most of your dimensions will be determined by the countertop you have available.

The most important dimension is the height of the finished bench. Working at too low a level will result in an aching back; too high will fatigue your arms and shoulders. Most countertops are set at 36 inches, so I maintained that height with my potting bench.

Build your bench frame on a flat, hard surface, preferably where the bench will stand when completed. Give yourself as much room to work as you can. I built the bench in the photos on my asphalt driveway, for the sake of working space and better lighting. The bench is now in my garden shed. I built my first bench in my basement, on a concrete floor, where it still serves today, about 15 years later. As you work, maintain solid, square joints and accurate dimensions. A little extra care now translates into a solid, sturdy bench for years to come.

Take a good look at the underside of your countertop. Most will have a lip running around the edge of the underside. Determine the thickness of the countertop. Subtract that from your desired height to find the length of the legs. For instance, my countertop was 1 inch thick, with a 1-inch lip. I subtracted 1 inch from my finished height of 36 inches for a leg length of 35 inches.

Using these measurements as a reference point, cut six sections of 2-by-4 (referred to as “board” through the rest of these plans) at 35 inches, taking care to maintain a square cut. Next, cut four pieces of board at 31-1/2 inches. Clamp one 35-inch board and one 31-1/2-inch board together, keeping one end and both sides flush, creating a leg 3-1/2 inches thick and 3-1/2 inches wide. Use the 45-degree side of a combination square to lay out a zigzag line from one end of the leg to the other. Use 2-1/2-inch decking screws to fasten the two halves of the leg together along this line. I used two screws for each “zig.” Repeat these steps on the remaining three sets of legs. The legs should be able to stand upright on their own without support. TIP: Drill pilot holes for each screw to avoid splitting the wood. Use a drill bit slightly smaller than the thickness of the screw’s shank, allowing full engagement of the screw’s threads into the wood.

For the next step, measure inside the lips of the countertop. This measurement, minus 1/8-inch, is the length of the cross members of the legs. In my case, the lip was 2 inches wide on the front and sides, and 1 inch on the backside, giving me a board cut measurement of 22 inches.

Cut three boards 22 inches long, again maintaining a square cut. Set one 22-inch board into the notched tops of two square legs, clamping it lightly in place with C-clamps. Use a framing square to maintain a square joint on both corners. Fasten a cross member to each leg with two screws per joint. Again, the assembly should stand free with no support. Repeat these steps with the remaining square legs and one of the remaining cross members. The remaining cross member and two half-thickness legs are assembled in a similar fashion, but will not stand on their own.

As I had an additional 24-by-25-inch section of countertop, I chose to use it as a secondary shelf beneath one end of the bench. To do the same, cut two boards at 27-1/2 inches to create support bars for the shelf. Measure up 4 inches from the bottom of the insides of one square leg set and the narrow leg set, and mark a line. Fasten one support bar to the inside of one leg of the square leg set, aligned with the center of the leg.

Tip: Lay the leg set on its side and rest the end of the support bar on a piece of scrap wood to keep the joint square.

The bottom of the support bar will be 4 inches above the ground when positioned properly. Attach the other end of the support bar to the inside of the narrow leg set at the same height, but flush with the outside of the leg. Check the shelf fit between the legs. Attach the second crossbar to the other side of the legs to create a square structure. Check for square and stability, and then cut two boards to fit inside the lip of the shelf, front-to-back. Attach to the tops of the crossbars to support the shelf.

Set one end of the countertop over the structure, settling the legs into the inset created by the countertop lip. Position the second square leg set beneath the opposite end of the countertop, and settle the countertop down on top. Adjust legs as necessary. Again, check for square and stability. Set the sink basin into position if you removed it earlier. Cut two boards the length of the bench, measuring from the outsides of the legs. Attach one board to the front of the bench, directly below the countertop, fastening each end to a leg with two screws. Attach the second board to the back of the bench in the same position.

Water can easily be plumbed to the sink, provided the faucet plumbing is still in place. Most faucets use flexible hoses with standardized fittings. Attach both hoses to a brass tee fitting connected to a garden hose adapter fitting. Wrap the threads of the fittings with white plumber’s tape to achieve a leak-free join. This assembly will allow you to connect a garden hose to the faucet. Set a 5-gallon bucket beneath each drain to catch water, which can then be used to water garden beds and flower containers.

With a little dreaming and innovation, you can easily modify these plans to add extra shelving, adjustable light racks, tool storage, and whatever else you may desire in your ultimate potting bench.

Andrew Weidman lives and writes in Lebanon, Pennsylvania. He is always open to the possibilities of repurposing and upcycling castoff items into useful tools or fixtures, and he likes sharing those ideas with others.