Last Saturday we had a break in the weather (no precip or wind, and temps in the 30's), and four of us put up the frame for a second rolling greenhouse. It's like the first one we put up in 2012, a 26' x 48' Rolling Thunder greenhouse from Rimol Greenhouse Systems. Even though it won't be heated, the enclosed airspace and solar gain help tremendously in extending the growing season here in New Hampshire.
We picked up all of the parts from Rimol at the end of February, foolishly thinking we'd have it up well before the end of March. February's weather was unusually mild, making us think maybe winter was over. Not so. We had four nor'easters in March, with lots of snow, wind, and cold temperatures. I remarked last year that it was only the second time in 100 years that March was colder than February. This year is the third, the second in a row. Changing weather patterns, for sure.
Our original rolling greenhouse was the first of our greenhouses from Rimol. This one is our fifth. We've learned as we've gone along, so we've become better at putting them up. A tip from John Wells, Rimol's sales rep, really helped with this one though. Being on wheels, the first handful of bows are extremely unstable, until there is enough structure to solidify the frame. On the original one, we had our tractor and excavator alongside, with ropes tied from the greenhouse to the equipment to brace it all. It ended up working, but there were a few scary moments. John told us to put the first bow in ground posts to lock it down, and then build off of it. After the rest of it was assembled, then we removed the first bow from the ground posts and put the wheels on that bow. Easy peasy. Thanks, John.
Our plan all along has been to have two rolling greenhouses, but the arrangement of them has changed. With our eight 26' x 48' growing plots (each plot has six raised beds) laid out in two side-by-side rows of four, we were originally going to put 200' rails on both rows of plots. Then we'd have one greenhouse on each set of rails. That would have given us an ABCD crop rotation for each greenhouse. However, the terrain here is not level to begin with, and Rimol recommends putting them on level ground. The ground where we put the first set of rails in 2012, was "fairly" flat, but not level. It sloped 4' over the 200' run, and one-and-a-half feet, plus or minus, from side to side. We leveled the ground side-to-side, with our tractor and excavator and laser transit, but decided to live with the 4' drop end to end, and so just smoothed it out flat, especially under the rails. When we move the greenhouse in the fall of the year, it rolls in the downhill direction a little easier than when we roll it uphill, but not enough to really matter.
We've always been advocates of having a good crop rotation for optimal soil health. But a lot of the farms we admire don't seem to put as much emphasis on it, because the soil is a lot healthier from no-till and generous amounts of compost and soil amendments. Because the ground where we were going to put the second set of rails and rolling greenhouse not only slopes more than the first, it also undulates considerably, we decided not to try and smooth it out. Instead, we put the new greenhouse on the first set of rails with an open plot between the two greenhouses. Now when we move them, there will always be an open space between them, and they will both have an AB rotation. Other than letting us get a head start on the winter crop before we move the greenhouses in the fall, the big advantage this will provide is that by being open to the atmosphere and weather every other year, salt and mineral buildup in the soil should be much less, which can be a significant problem in stationary greenhouses.
Now we have to put up the end walls, with doors and vents; wire up the thermostat, vents, and inflation blower; put on all the wirelock; and cover the top with a double layer of poly and wiggle wire it down.
With the extra greenhouse, Laurel is doubling the amount of tomatoes we usually grow, and she's adding some warmth-loving crops that should do a lot better inside, like melons and okra. Stay tuned. ---Steve