Monday, September 21, 2009

The Nights Are Getting Cooler Now

With the coming of cooler autum weather, our thoughts have turned to season extension.
A solar greenhouse would be nice, but as many of you who have visited the Murray Hill site will have noticed, space is at a premium! We haven’t ruled out a solar greenhouse yet – but siting it properly will take some doing in our limited space.
Other possibilities for season extension are much more achievable in the near term. We are planning the construction of some cold frames, as always trying to use up scrap wood from our dwindling lumber pile and possibly using some old glass from a window renovation we just found out about. We have done a bit of reading about low tunnels, high tunnels, solar pods, etc and find some of those ideas interesting.
Our current project and first attempt at shielding at least part of our crop from the elements is our tomato ‘hot house’ as we’ve taken to calling it. The idea originated with a similar project that we implemented to shelter our seedlings on the side deck at Murray Hill. The seedling flats would tend to fill with water during the ‘monsoon season’ resulting in drowned plants. Our solution was a seedling table made from scrap cedar planks (left over from our deck construction seven years ago) laid over a couple of sawhorses. We attached a few uprights and crossbar to the sawhorses and to the crossbar we attached a length of 6 mil poly which rolls up out of the way when the sun shines and rolls down over the seedling table when it rains. It took no time at all and has worked well for us.
When we realized our tomato crop was in a race against cooler weather on the way, we looked at how well the seedling table functioned and came up with the idea of tenting the tomato trellis with 6 mil poly arranged to roll up and down as the weather dictated. The almost finished result doesn’t work quite as well as we had hoped (rolling it up and down will get to be a chore) but it does provide some additional daytime heat to the ripening tomatoes and will work well to shelter them on those frosty nights which are rapidly approaching. We may alter this layout, for example if the wind blows it around too much (or completely carries it off some windy night!) but for now we’ll see how well things work. It would improve it greatly to close the ends and place some thermal mass in the garden (water filled jugs painted black?) and we might go that route. Of course all this just makes us want to move directly to putting in a solar-heated greenhouse. We’ll see.
The walk-in cooler has been functioning as such since about the middle of August, but there are a few important refinements that still need to be done. The most important of all, of course, is modifying the 8000 btu air conditioner to run cooler than 60 deg F. We are part-way there, but one of us just needs some time to sit down with a pencil, paper, some circuit components and soldering gun and come up with a fix to fool the a/c into ‘thinking’ it’s much warmer in the cooler than it really is. There is more to it than that , but that’s the basic concept we’re working with. Like many of the things we are doing in this urban farm operation, we are trying to balance what the ‘experts’ say is possible with a little experimental tinkering to see for ourselves and maybe prove them wrong.
Other projects still to be completed are the rain barrel irrigation systems at the various fields, Bob’s bicycle water pump idea, Bob’s cheap homemade bike trailer idea, etc, etc . . .
As Steve Earle says . . . days are never long enough.