DIY Build- Solar Seed Benches, Greenhouse heat sink benches

I’m struck with early onset Alzheimer's each and every time one of our seed orders arrives….the postwoman or man with this impossibly small parcel…. “What did we order honey?” I exclaim to Mackenzie only to realize our $1,000 seed order is contained within this nondescript, imperceptibly small 10”x 8” box. It’s incredible really! Enough seeds to envelope an acre with lacy pastel hues and vibrant coral yarrows, draping tendrils of deep magenta amaranth and blazing poppies shooting towards the sky reflecting the efficacy of the sun within their own glorious orbs of light.  Considering the bees and butterflies, birds and frogs… much energy is contained within this little box?  It’s no doubt the biomimicry nuclear energy must have stemmed from!

“We’re going to need some more start tables in the greenhouse, aren’t we hun?” It was a bit rhetorical, our old ones needed updating anyhow.

As the TopaFlora greenhouse is “off-grid” I decided to engineer something functional as well as dual purpose, in this case I eked out threefold. Not only are they seed benches, they’re passive solar heaters, as well as garden tea brewing vats & organic weed control containers (soap and vinegar)!

What you need to make two benches:

(keeping even numbers of tables optimizes materials)

3# 55 Gallon Water Drums = $90                      Staples =$1.00

32# 2.5” Wood Screws = $ 2.00                         6# 1” Wood Screws = $1.00     

2# 27” x 8’ Ribbed Steel Lath = $17.00             2# Cans of Black Spray Paint = $6.00

4# 2x4 x 12’ =$17.00                                             2# 1x4 x 12’ = $9.00

2# 2x4 x 8’ =$8.00                               Total =     $150     

$75 per bench seems kind of expensive compared to our pallet benches, conversely Home Depot has a 3.5’ bench for $86, which seems comparatively exorbitant at $24.50 pr linear foot when compared to our $6.25 pr linear foot. Two benches will fit 28 seed trays. If you do only one table (or an odd number) the odd table out will cost $10.25 pr linear foot and will have 4' of  unused lath.

Tools Required:

Saw                         Tape Measure

Screw Gun              Tin Snips

Staple Gun

Let’s get started!

Cut 3# 23.5” pieces from each 8’ 2x4

You should have a 25.5” piece left, cut that in half.

Be sure to get the steel lath which is more sturdy, specifically called “High Ribbed Lath”, a bit more expensive but is worth it.

Screw two of your 23.5” pieces perpendicular to the ends of your 12’ pieces of 2x4, you should end up with a large rectangle.  Align both the 23.5” 2x4s, ¼” below the 12’ 2x4, your lath rib will sit in there and lock the steel sheet into place.

Now screw your third 23.5” piece across the middle of your large rectangle ¾” below the 12’ long 2x4.

Then take your little 13” pieces of 2x4 and “scab” them onto the outer 23.5” pieces.  You’ll want to do this on the inside of your large rectangle, level with the top of the 23.5” piece.

Lastly set your 1x4 x 12’ on top of the scabbed on pieces and supported by the center brace. Don’t screw it in yet.

Repeat this process to make your second 2x4 x 12' rectangle.

I got these really great 55G drums off of craigslist.  I made certain to get drums with a removable lid, instead of just the common two hole setup, because I want to be able to make garden tea and clean the drums at the end of planting season.

Now get your drums nice and level and put your 12’ 2x4 rectangle upon your 55G drums, right in the middle of the second drum (the one in the middle of your 24’ span will be supporting your next table as well).  Put your 8’ steel lath on top of the rectangle and cut your second 8’ piece of lath in half. Adjust the 1x4 so that it rests in the middle of 2 ribs of the lath.  Now staple your lath to the 2x4”s and screw your 1x4”s to the blocks it’s resting upon.  Once you have everything the way you want it, fill the drums up with water.

Put the second 2x4 x 12' rectangle on your third drum and the other half of your second drum. Staple your 8' and remaining 4' lath and screw the 1x4 down.

Since I’m making tea I made these large 2x4” “T”s  now I can lift the whole table off of the drum and rest the greenhouse table upon my large “T” to then access the lid.

Be sure to crack your lid for a bit for expansion and contraction and I added ingredients for our garden tea. Note: You will need 2 "T"s if you do tea in a drum which has two tables on it. I've done water in the center drum, with soap and vinegar to prevent algae growth, which may be used as weed killer periodically or at the end of the season. Only my outer 2 drums have tea.

I painted the drums black (thanks to a suggestion from our beautiful Facebook friends!) As the greenhouse warms during the day the drums absorb heat.  During the night our little nuclear seedlings are kept warm due to the latent heat of water.  

I zip tied some drip misters down the middle. The Imperial Stars seem to like it.

Mackenzie is happy!

The sweet peas are frothing at the bit.

                                                                                                           Achieved 98.6% germination off-grid!

   Stock 7-14 days germination popped up in 5!                         91% Germination rate on package


D-Bo’s earning her keep on mouse patrol! (Although thinking about it now...the mice were previously excavating each cell of our trays for the little seed kernel when we had pallet tables.  I don’t think they can climb the drums…..Murphy's law the little acrobats will find a way!)

I imagine the lath will rust somewhat quickly, I’ve considered spraying a lacquer to slow the process but I also think that replacing the lath every 2 years, at $1.00 pr linear foot is a reasonable cost to incur.  Conversely that is a consumerist mentality and I would love any suggestions or insight from our brillant readers!

Build, expand and add your ingenuity to this post! We cherish your support on Instagram or Facebook; and please don’t hesitate to email us with any questions or farming topics on your mind.