Thursday, May 7, 2009

Finishing the Greenhouse Construction

I have had a couple of email questions about tomatoes and about how my extra-early tomatoes are doing. There was also a comment from Amber asking for an update on our Greenhouse. These are related topics because we will not have ripe tomatoes in May this year due to how slow I was in finishing the Greenhouse. Renee and I built most of it last Fall, but there were several things not completed that prevented the early tomatoes from going in there in time. The tomatoes are doing well and I will post specifically about them later. Its just that I don't think they will be ripe early enough to beat last year's record of June 5th.

The good news is that I finally completed the rest of the Greenhouse construction. The things left to do this Spring were:

  1. Install an exhaust fan and run electric to it
  2. Build windows to use as vents
  3. Build inside grow beds and fill with soil/compost
  4. Extend retaining wall and back fill for future greenhouse expansion

That proved to be a little too much to accomplish quickly, but it is now almost complete. The first item on the list was the hardest and the most important. Most people think that a greenhouse needs to be hot, and that is true during cool weather. The biggest struggle with a solar greenhouse is that in the Spring and Summer it can get TOO hot. This time of year is particularly difficult because nights are cold and sunny days get hot. With all of the vents closed up for the night, our greenhouse can easily get to above 120 degrees by mid-morning. The new exhaust fan is thermostat controlled to come on and expel the hot air in that scenario.

Here is a picture of our hoop house from the back where the fan is:

I was able to install the fan myself.


Getting the fan put in place was all I could do since I am not an electrician. Later I had an electrician friend come to run the electricity to the fan. In the meantime I set about completing the other items on the list.

I built the windows so I could have flexibility in how much venting to allow each day.

Then I built the raised beds along one side and along the back. This is not a requirement for all greenhouse structures but it was in the book  The 12-Month Gardener by Jeff Ashton, where I got the plans from and I think it will be a great way to grow lettuce and spinach all winter long.

The hardest part was getting the wheelbarrow in to fill up the beds.

I was able to put boards down as plank ramps to go up and in.

I also had to tackle the retaining wall. The spot where we placed the greenhouse didn't naturally fit there. There wasn't enough space for it so we had to build a retaining wall and then fill in behind it with fresh dirt. Originally I wanted the greenhouse to be 14 feet by 24 feet. Since we had to move so much earth, we only built half of the wall and then built half of the greenhouse. Next year I want to expand to the full 24 feet so the rest of the wall needed to be put in and back filled.

I moved about 50 wheelbarrow loads of dirt from the spot I dug out to fit the chicken coop in (more on that later). I forgot that we would need to run the electric through that space, so I had to dig part of it out again to make the trench for the electrician to run the pipe with electric wires in it.

My electrical friend came over and did a great job with the pipe and the wiring.


He was able to splice in to an existing outside outlet that used to power a swimming pool pump.


He put in an outlet and switches to control a light that we will install later and the fan.


And finally, here is the fan working!


Now we can put plants in our greenhouse without worry of them getting too hot.


We may not have been able to use it much this spring, but from now on this greenhouse will grow thousands of plants for us. Our goal is to be able to harvest something from the garden in all 12 months of the year by leaning heavily on this structure in the winter. I'll show you more as we get it all going.

This greenhouse was a little more work than I thought it would be, but it feels good knowing that we built it ourselves from scratch with only a little help from our electrician and a lot of help from The 12-Month Gardener. What a great book that is!

Happy gardening!

- Marc


Staci Severns

Looks like you’re doing great in your Greenhouse construction! It’s definitely a good idea that you installed an exhaust fan with a thermostat. With thermostat, you won’t have to worry about the temperature inside your nursery because it will be regulated. Essentially, that will help create an environment where your plants can thrive. Maybe you can document the progress of your greenhouse by taking pictures of your plants every month!

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