Sunday, March 24, 2013

How to build our 8 tray seed starting bench


     This seed starting bench is designed to hold 8 standard 10" x 20" seed flats directly in front of 2 double hung windows.  One light fixture can be supported by the unit, the upper fixture is hung from the ceiling above it.

Tools Needed:

Measuring tape
Straight edge
Drill / driver
Saw (for crosscutting lumber and ripping plywood) 
Framing square

Shopping List: 

(Use this list if you are planning to buy all new materials)
(Prices are based on my current local prices for these materials and are for example only)

Quantity               Material               Actual Size           my current local retail price
1                            2' 1x4"                 3/4" x 3 1/2"                             $1.09 for 47"
7                            8' 1x2"                 3/4" x 1 1/2"        $.78 each =  $5.46
1                            4'x8' x 1/4" plywood                                             $9.47 for luan
1                            4'x8' x 3/8" plywood                                             $13.57 for CDX
18                         2" wood screws                                                      $2.97 for 25
37                         1 1/4" wood screws                                                $3.29 for 50
51                         3/4" wood screws                                                   $3.79 for 100
                                      Total example price for all new materials =  $39.64

Cut List:

(Use this list if you are planning to salvage materials)

Quantity             Length            Material                               Piece Name

10                       4'                     1x2"                             Legs and Side Rails
6                         20 1/2"            1x2"                             End Rails
1                         3' 7 1/2"          1x2"                             Top Support
2                         15 3/4" x 3' 7 1/2" x 1/4" plywood      Side Walls
2                         15 3/4" x 1' 8" x 1/4" plywood            End Walls
1                         1' 8"                 1x4"                             Light support
1                         3' 9" x 1' 10" x 1/4" plywood              Bottom
1                         3' 9" x 1' 10" x 3/8" plywood              Shelf
1                         4' x 1' 10" x 3/8" plywood                   Top

Please keep in mind that 1x2 and 1x4 is given in nominal dimensions and the actual size of these boards are 3/4" x 1 1/2"  and 3/4" x 3 1/2" respectively.

Easy to salvage materials:

All the plywood needed for this project is in pieces less than 2' wide and under 4' long allowing for a great many salvage opportunities.  Other thickness can be used though some measurements may need to be adjusted depending where the pieces are located.  The 1x2" (3/4" x 1 1/2" actual) material that is used for most of the frame can be ripped out of any 1x or 2x dimensional lumber available if you have access to a table saw.

Step 1:

Create a side wall frame by attaching 3 side rails to 2 legs as shown below.  Use 2 of the  1 1/4" screws on each connection.  Pre-drill these holes to avoid splitting the wood.  Use a framing square to ensure good 90° corners.

Step 2:

Repeat step 1 and make a second side wall frame

Step 3:

With the side rails facing out, connect the two side wall frames using 6 end rails as shown below.  Use 1 of the 2" screws per connection to complete the frame.  It is helpful to have someone hold the pieces at this stage.  Be sure assembly is square.

Completed Frame

Step 4:

Install side walls to inside of side rails as shown below, leaving approximately 1/8" of frame exposed above and blow the plywood.  Attach using 10 of the 3/4" wood screws for each panel.  You do not need to pre drill these connections.

Step 5:

Attach End Walls to inside of end rails using 6 of the 3/4" screws per panel.

Step 6:

Install bottom support centered to inside of side walls as shown below.  Attach using 4 of the 2" wood screws through both bottom side rails and side walls.  Pre drill these connections to avoid splitting the wood.

Step 7:

Attach bottom using 19 of the 3/4" wood screws as shown below.

Step 8:

Install the top support to the center of the Top End Rails using 2 of the 2" wood screws as shown below.

Step 9:

Install the Top using 13 of the 1 1/4" screws

Step 10: 

Finish as desired, we used a coat of all purpose primer followed by an exterior latex house paint.  Stain or penetrating oil can also be used but some measure should be taken to protect the wood from the moisture involved with planting.

Step 11: (Optional)

Install incandescent light fixture to bottom support for heat source.  Be sure to follow local electrical code.

Step 12: (Optional)

Drill 8 medium size holes in shelf to allow heat to reach the bottom of the seed trays.  The holes should be centered so that 2 holes are heating the center of each tray.
Set shelf in place,  it does not need to be fastened.

That's it, you are ready for planting!


  1. Nice set Joe!
    Seen your link on a garden forum. Building mine this weekend. Weather has been terrible. I also run one acre and just moved in two years ago and have been busting butt to put in my gardens and landscape beds. I'll add you to my reading list. I have a blog as well where you can see many pics of my garden and landscaping. Looking forward to a good gardening season this year. Cheers!
    The High Cost of this Low Living

  2. Thanks Bushman,

    I enjoyed your blog, the writing is very open and honest, which is refreshing. Will be on my reading list. Let me know how the build goes, I am anxious to hear how the plans work out for someone else. Hopefully Ma nature will be a little kinder to us this season than last.