Sunday, February 26, 2012


 I decided that while I had the excavator at my house, I would expand my garden and turn it over.
 After digging the trench around the perimeter, I dropped in the air tubes and backfilled with some 2A modified stone, and then lined the trench with 2-foot sections of pink board overlapped.
After backfilling, the two 30-foot sections of tubing stick up out of the ground on opposite sides of the dome.  I thought it would be better to have 2 shorter tubes for heat exchange than one long one.

Now I know that you should always take estimated completion time and double it, but this was ridiculous.  A circular trench, working in a tight space, and no experience all made for a very long day!  Geoff, if you're reading this, thanks again.  Getting to drive the trackhoe is fun for a while, but after 6 hours it's just another hard job.  I couldn't have done it without you!

Saturday, February 25, 2012

Mockup of Base

Each strut will be cut with at a 12-degree angle, recessed so the connectors fit flush.
 For the mock-up, I have only attached a connector on one side.
I will have to disassemble all before I start to dig, but I needed to know the exact diameter of the greenhouse.
 Here is the completed mock-up.  With the added length of the connectors, total inner diameter is 18.5 feet.
 After centering the blocks that will become the base, I sprayed the outer perimeter orange.
 3 yards of stone to protect the underground tubing and make the floor of the greenhouse.  It doesn't look like it will be enough, but I will make it work.
 1" foam board, cut into 24"x36" chunks. This will protect the foundation perimeter from frost.

Thursday, February 23, 2012

New Blog for the Serious Gardener or Solar Enthusiast!

I am a big fan of self-sustainability, if such a thing even exists.  I want to grow my own food (lots of it) all year around.  I would also love to do it with a minimum of fertilizer and water.  Not that water is especially scarce where I live, but it can get expensive.  At my old house in Easton, PA, using a hydroponic system, I was able to maintain a 60 sf garden on 5 gallons of water per week during the heat and dry of August, and all of that water was collected in my rain barrel.  Not a drop came out of the hose that summer, and I got a good amount of delicious produce, although it was just a small experimental garden. 

My new greenhouse will be a dome.  After seeing the one at the Rodale Institute in action, I just had to have one! This is my second homemade greenhouse after my first attempt at urban gardening.  With a new home in the country, I have more space for a  bigger greenhouse!  This one will be about 18 feet in diameter.

Another extremely important requirement is heat retention.  I want to be efficient with both water and energy, and the greenhouse must not freeze even during the coldest of days in January.  After considerable research, I have settled on an insulated foundation with a subterranean air heating system.  For this I will need to dig to our 36" frost line.

I have the excavator ordered for delivery this Saturday, but I have no idea how I am going to dig a round foundation to line with pink board.