Improvements to Hoophouse

Catarpillar Tent Update

In our last post we described two caterpillar tents we constructed -- one to protect a bed of beans and the other to protect some squash. The tents worked very well until a 45 MPH wind blew one to pieces and the other to the ground. We tried some modifications which seemed to help a bit. The first tents used 10' hoops and a four-foot-wide placement. We lowered the height gradually by moving the rebar further apart. At eight feet wide the tent could withstand the wind pretty well. Another problem was that winds caused the weights (dirt-filled pots) to tip over. We decided to fill some feed sacks with dirt to supplement the pots hoping they would blow and this worked pretty well. We also tried putting hoops 4 feet apart instead of 5 feet.

Now we have a couple of wide tents over carrots and broccoli and the new concern is that the first snow will pretty much crush the tents so we plan to try 7-foot hoops and a five-foot wide bed. We will report again as we improve the design.

Our Four Season Hoophouse

We have set an objective to grow cool weather crops through out the winter to deliver to the local market. To get from three season to four season we need to add heat and light and save as much heat as possible. We also want to do it without using any energy other than solar. To accomplish this objective we have put together the following plan:

Add heat: We are building a hot compost pile four feet high, six feet wide, along the 70-foot length of the hoophouse and right up against the plastic. It seems necessary to be against the plastic to keep that side of the pile moist so heat will be conducted into the house. Our first attempt was a twenty-foot pile built from horse manure and wood shavings from a local stable mixed with grass clippings and other materials. This pile heated to 150 degrees in three days and appeared to be working. The inside plastic felt only mildly warm but that seemed reasonable since any heat that reached the plastic would rapidly diffuse into the house. We uncovered an immediate problem: pressure from the pile was pushing hard against the plastic so we decided to take the pile down, add some battens (See picture. We used 10' by 1" grey pvc conduit) between the hoops and outside poly to reduce the pressure, and then rebuild the pile. Further plans for adding heat:

1. Add white plastic liner inside plastic on north wall to bounce light and heat onto plants.
2. Add white plastic ground cover on ground outside south side of house.

Conserve heat: 1. Insulate north side of hoophous (between outside poly and white liner). 2. Seal all doors and other openings to eliminate all airflow in and out.