Build a Seed Starting Rack

For several years now we’ve tried to start most of our own vegetables (and lately flowers) for our garden from seed. In the past we’ve used a plastic folding table and while it worked, it also took up a lot of space and wasn’t the most attractive thing to look at. So I thought that I would build a rack large enough to hold all of our seed trays, heating mats, and grow lights.

A rack with books and seedling trays.

I started by cutting the shelves and top from a 1/2” sheet of MDF. (Note that most local Home Depots will cut the sheet at least once to make it easier to manage.) In order to fit our four seed trays on a single shelf along with our 4’ lights, I made the shelves 24” deep by 47” wide. I left the top 49” wide (MDF sheets are actually 49” x 97”) so that it would extend a little over the tops of the legs.

A circular saw is used to cut a large sheet of MDF.
A circular saw is used to cut a large sheet of MDF.

For the shelf frames and the legs, I decided to use pre-surfaced pine boards from Lowe’s to avoid having to use the jointer or planer. To ensure that the matching parts were identical lengths, I used a stop block for the frame pieces and for the legs I cut them to rough size first and then made a final cut through both pieces at the same time.

A miter saw is used to cut a pine board.

To save a little money I did buy 1x8 boards and rip them to size at the table saw, but if you don’t have a table saw you could simply buy 1x3 boards.

A table saw is used to rip a pine board to width.

Once all the parts were cut, it was time to assemble the frames.

Several cut pieces of pine wood are stacked together.

I kept the frame assembly simple and used pocket-hole screws to attach the short rails to the long rails while making sure everything remained as square as possible.

A pocket-hole jig is used to drill holes in a wooden board.
A drill is used to screw two pieces of wood together.

After finishing the frames I clamped down each piece of MDF to its frame and sanded the edges of the MDF flush.

A random orbit sander is used to sand two pieces flush.

To protect the front edge of the MDF shelves and top, I decided to cut a small 45° bevel along the front edge at the table saw.

A table saw is used to cut a bevel down a piece of MDF.

It was then almost time to paint, but I first cut several small blocks from an old 2x4 to raise the MDF pieces off the floor.

A table saw is used to cut a 2x4 into small blocks.
Small blocks are used to raise MDF panels off the floor.

To prevent any bleed-through of grain and knots on the pine parts, I decided to use a shellac-based primer for everything. It’s pretty runny, but applying two coats with a 4” foam roller was fast because of its quick drying time.

Three pieces of MDF are primed.
A 4" roller is used to apply primer to a frame.

After a quick sanding and wiping, I applied two coats of latex paint to both sides of the shelves and top as well as the frames and legs.

A 4" roller is used to apply primer to the legs.
Brown painted MDF shelves and top.

To make it easier to assemble and disassemble the rack if need be, I decided to use 1/4” bolts, washers, and nylon lock nuts. Note that round-headed bolts would work fine and would avoid needing a counter-sink bit – my store just did not have enough in stock. I also purchased some small right-angle brackets to attach the MDF shelves to the frames.

A pack of stainless steel bolts.
A pack of stainless steel nylon locking nuts.

I marked off where the holes on the legs should go and then drilled the holes at the drill press table. I then drilled counter-sunk holes in the legs.

A drill press is used to drill holes in a wooden leg.
A cordless drill is used to drill countersunk holes.

After marking off where the holes in the frame needed to go, I drilled those by hand.

A square is used to mark the location of a hole in a frame.
A cordless drill is used to drill a hole in a frame.

And before moving everything into the house for assembly, I attached four right-angle brackets to the tops of all the frames.

A square is used to mark the location of a hole in a frame.

To attach the tops I laid them face down and then aligned the frame so that the rear and side edges were flush. Then I made a small mark for the screw locations using a Philips head screwdriver and moved the frames back out of the way.

The frame is laid on the bottom of the shelf.
A screwdriver is used to attach the frame to the shelf top.

I carefully pre-drilled small holes for the screws using a piece of tape on the drill bit as a depth guide. Then it was just a matter of moving the frame back into position and using some small screws to hold it in place.

The frame is laid on the bottom of the shelf.
A screwdriver is used to attach the frame to the shelf top.

To attach the legs to the frames, I started at the top and just used a screwdriver and socket wrench to secure it to the leg with a bolt, washer, and lock nut.

A leg is attached to the frame with a screwdriver and wrench.

I then just worked my way down to the middle and bottom shelves and then attached the front left leg before finishing up with the right legs.

A leg is attached to the frame with a screwdriver and wrench.
Another leg is attached to the frame with a screwdriver and wrench.

And with that, it was finally finished and ready for some lights and some seeds.

A leg is attached to the frame with a screwdriver and wrench.

To help with seed germination we use a pair of 20" x 20" heating mats that are controlled by a digital thermostat which makes it great for starting seeds early in a cooler room.

A heating mat is placed on a shelf.
A digital thermostat.

For lights, we’ve been using a pair of T8 fluorescent shop lights with a 7-Day timer, but we’ll probably switch to brighter T5s next year. We also like using the heavier duty seed trays as they don’t bend when weighted down with dirt and plants.

Fluorescent lights are hung above a shelf.
A plastic dome is placed over a seed tray.

After 5 or 6 days on the heating mats, most of the seeds other than our peppers had germinated and it was time to remove the covers.

Several small labeled seedlings in trays.

Hopefully they’ll continue to do well and in a couple of months we’ll be able to do a quick garden tour. If you’re into gardening leave a comment below and let us know what types of things you’re growing this year!

A seed starting tray with books, seed trays, and a watering can.

Materials and Hardware

  • (1) - 1/2” x 4’ x 8’ MDF
  • (3) - 1” x 8” x 8’ Pine Boards
  • (48) - 1-1/4” Pocket Hole Screws
  • (12) - 1/4-20 x 2” Oval Phillips Machine Bolts
  • (12) - #12 Flat Washers
  • (12) - 1/4-20 Nylon Insert Lock Nuts
  • (12) - Right-Angle Bracket

Seed Growing Materials

Tools Used

Be sure to check out Our Workshop page for more details.

Plans

Plans for this project are available as a PDF or SketchUp file.