Greenhouse construction update

Building this greenhouse was actually the motivation for me to start this blog. Today, I am finally getting around to an update of the progress of its construction- mainly with some pictures.
I have written a few posts about the greenhouse; a general description of the green house is here, plans for the greenhouse can be seen here, and my plan for heating the greenhouse is here.

In general, I am constructing this greenhouse out of recycled materials, and I have designed it to be energy efficient with the site and our latitude in mind. Our plan is to grow hardy vegetables in the greenhouse all year long, and use to it start plants and extend the growing season by a couple of months for warm weather vegetables (read: hot peppers).

It has been a really fun project, learning about greenhouses, designing the greenhouse and accumulating all the pieces. Since it is almost all made from recycled or reused materials, accumulating the parts has taken a while

Site preparation was slow- I had to remove and pot up all the plants that were in the greenhouse footprint, including 50+ bitterroots. This was compounded by my eagerness to begin the project this spring and the reality of having to wait for many species to come up.All these potted plants filled up our nursery and even filled up space in all our raised beds. We will grow these plants for another week, and transplant them to our front yard- where we started a little makeover project- more on this in another post.

Also, we will probably donate some of these plants to the Clark Fork Chapter of the Montana Native Plant Society's annual native plant sale- at the Missoula Farmer's Market on May 16th. Depending on the quantity and diversity of plants he have left over, we might even have a plant sale of our own at the Missoula Farmers Market in late May or early June. Below, all the plants are removed from the greenhouse area.

Initial grading and 8" compacted gravel base, onto which the treated 4x6 foundation was installed, and secured to the ground with lengths of 36" re-bar.

After a lot of deliberation, and a lot of advice, I finally decided to use just a compacted gravel base and pressure treated wood foundation for the greenhouse. I considered almost every iteration of building a foundation. My friend Barry finally convinced to me to build it this way (if it goes wrong, it is his fault). Actually Barry is a fantastic carpenter and builder, so I totally trust him.

Below is the compost furnace before going into the ground. It is a 30" x30" x 36" deep box, insulated from with ground with 2" rigid insulation. I installed it on top of 4" of cobble/ gravel for drainage. You can read about the compost furnace here- if it works it will heat the greenhouse in the winter. If it does not work, we will have great storage in the greenhouse- either as a root cellar or as my wife puts it, a place to store sweaters in the summer.

Below is the compost furnace installed, notice the 2" rigid insulation over the part of the greenhouse that will be covered with brick flooring.
On top of the insulation I laid down landscape fabric and 4" of compacted gravel (see below). The insulation should keep the floor warm and restrict heat loss to the ground. Below, you can see the greenhouse floor and the separated part to my left is for a raised bed (on the south facing side of the greenhouse).

The next step is to lay down 1" of sand and install the brick flooring. The brick is 100-year old salvaged Missoula brick. It should make a really nice floor.