It’s time to plant spring seeds!

Now that we have passed the Winter Solstice and the days are growing longer my heart has turned to visions of of my garden finally  being perfect this year.  Ok, it can’t be perfect because I have a zillion ideas, BUT I’m ready to fill it with the wonderful seeds I ordered from Johnny’s this year!

As friend of mine recently confided, seeds can be tricky to sprout and grow into a usable plant. One of the things that has made our lives easier out here on the farm is having a heated seed box.  Check out these plans to build your own heated seed box. You can modify this to be the size you need.  If you have a smaller space then you can try building one without legs that sits on an existing table.  This will give you the basics.  This seed box was build 5 years ago and is still running strong!

While all seeds do not like to be transplanted, some are fine with it. Start your seeds in this tray and when they are big enough move them to 4″ pots. This design has part of the box not heated for seeds that like it cooler. Read the back of the package to see which seeds prefer a warmer start. You can make your’s smaller and seed mats come in different sizes.

Seed starts give you a jump on the season and let you grow plants when you would normally just be doing your yearly prep and maintenance. You can transplant your starts outside when appropriate.

Materials for a Heated Seed Box

Materials list for your heated seed box

2 8’x4″x4″ pine or treated

2 2′ 2″x4″ pieces

1 3/4″ sheet plywood

4 brackets

2 2″x6″x6′ pine or treated

2 3’x5′ plastic sheeting

1 1/2″ wood screws

Wondering whether to choose pressure treated or pine for your seed box? Consider these points:

  • Pressure treated is more expensive, but can last a very long time.

  • Pressure treated cannot be used in organic production

  • Fir boards are very inexpensive.

  • If using economy 2″ x 4″ make sure to examine the pile and pick the boards for the best boards possible

  • The part of the table that comes in contact with water is protected by plastic, so rotting is not an issue.

  • SCRAP WOOD WORKS! Just make sure it’s not rotting.

Build the Tray:

We cut each 2″x 6″ board into a two foot and 4 foot piece.We then screwed the edges together as shown. Notice that we put the 2′ piece on the inside to insure the inside was 24 inches. We cut the bottom (plywood) to fit. We left one corner with only one screw in so that we could wedge the bottom on snuggly and then screw it in from the side. Once in, we screwed the corner in tight.

Cut your wood for your heated seed box

Reinforce the bottom:

Uses scrap wood or new if you have it to reinforce the bottom.

We had 1″x2″pieces lying around so we used these.

Again, screw them from the side. The gap that is left in the corners (between the plywood and sides) will add stability to the legs.

Secure the Legs

Secure the brackets to the box first using the screws.

Next secure the legs.

They will be a little unstable and there will be an overhang on the bracket.

Secure the legs on your heated seed box
The overhanging bracket is important

See the overhanging bracket?

That’s a good thing.

Hammer the bracket around the corner for a snug fit.

See how nicely that fits?

Make sure to screw it off.

The hammered bracket fits perfectly.
Secure your legs from the top with screws

Securing the Legs from the Top:

Carefully turn over the table, being careful not to jostle the legs.

Screw the legs from the top with two or three more screws to give that final stability.

Line the bottom with plastic.

Staple the bottom down.

Line the bottom of the seed box with plasic.
Install the heat mat in your heated seed box.

Insulate and add the mat:

We used a yoga mat–obviously not in use– for our insulation.

We put the heating mat (designed for plant trays) in and then affixed the cord with electrical staples to keep it from moving when we are digging around in the tray.

We wanted there to be room at the other end for starts that don’t like warmth on their roots.

This makes for smart use of space when doing your starts.  You just pot on from the box.

Finish it up:

Now cover the table with the last piece of plastic. You will be able to wrap it all the way over the edge and under the bottom for a nice clean look.

Carefully tack down the plastic on the bottom at the edges with a staple gun, being careful not to puncture the heat mat.

Then pull down and over the edge, securing with the staple gun. Now sit back and enjoy your work.