Saturday, December 10, 2011
Posted by Kate at 1:01 PM
I promised another post on the features of our hoop house. Despite the fact that it's still not quite complete, the hoop house is doing well and demonstrating its productivity. Typically, protected growing space is some of the most expensive in any garden or on the farm. Our hoop house was definitely no exception. I don't have a figure for what we've spent on this project, but I'm guessing it's close to $1000 all together. That makes it about $10 per square foot of growing space. And given that our laying hens are occupying one-third of that, the productivity of the remaining two beds is under a lot of scrutiny. I know we'll get many years of use out of the hoop house, and thus the cost can be amortized. But I'm still very conscious of needing to maximize the value of that space.
The seeding of the hoop house, like everything else associated with this project, was a day late and a dollar short this year. Mostly it got planted at the end of September and very early October. Nonetheless, most of what I planted seems to be doing at least tolerable well. I experimented with turnips (planted a little too early, if anything), cylindra beets and some piracicaba broccoli (probably a tad late), catalogna dandelion (doing very well, wish I'd planted more), many transplanted volunteer lettuces and cilantro from the main garden (all looking happy and gorgeous), tatsoi (happy, but seems to be beloved of whichever pest found its way into the sheltered space before winter arrived), carrots and scallions (very happy and well timed) a few snow peas (rather small, but seem to be hanging in there), some sort of Asian brassica that I got on sale from Johnny's (nice cooking green, another one I wish I'd planted more of), as well as a few perennial herbs which seem to be biding their time. So I'm well rewarded by the sight of happy plants each time I go out to the hoop house. That said, I mostly want to show off a bit of the infrastructure today.
The hens are once again overwintering on deep bedding. As usual the bedding is primarily free wood mulch from the yard waste facility in our township. This year I also put some fallen leaves in there. These high-carbon materials will absorb and balance all the manure (high in nitrogen) laid down by the chickens during the four months or so of their winter confinement. In my experience during the last two years, the litter never smells bad and the girls constantly scratch through and mix their wastes into it. In the spring what is left is a rich, inoffensive, bioactive, nutrient-packed fertility mulch for my fruit trees. I was asked whether this didn't pose a risk to these trees, since excessive nitrogen can lead to fire blight on growing trees. I haven't seen that on the pear and apple trees that have benefited from previous years' litter treatment. My feeling is that because there is so much microbial life in the litter, most of the nitrogen and other nutrients are bound up in the bodies of living things, and thus only become available to other organisms where the litter is laid down very gradually. This is a far cry from what happens when sterile chemical fertilizers are dumped into the ecosystem of the topsoil. I will be watching the bedding closely however. We've got more hens this year, and less square footage per bird. The rule of thumb that Joel Salatin proposes is a minimum of four cubic feet of deep litter per bird. Supposedly at that stocking density the litter will never turn nasty. We're right up against that number, so we'll see what happens.
There are a few major benefits of the hoop house over the shed, as far as winter housing for the hens goes. The first is that we didn't have to sacrifice one third of the space in the shed to them this year, and won't ever have to again. The second is that the deep litter bedding in the shed, being raised up off the soil, sometimes froze solid, despite the carbon-nitrogen balance that should have provided for enough microbial activity to keep the pile generating its own heat. This required me to get into the bedding and turn it over with a pitchfork from time to time, otherwise the manure built up on the frozen surface. It's certainly true that we haven't seen the worst of the winter weather to come. But given that the lack of air space under the bedding, I very much doubt the bedding will freeze inside the hoop house. The other main benefit is the added light and warmth of the hoop house compared to the shed. The doors of the shed face north, so the hens got no direct sunlight at all in previous years. I did open the doors all day in all but the worst weather though, so the temperature was always cold in the shed. The hoop house gets cozy warm inside on sunny days, even when the temperature is well below freezing. This saves on feed costs for me, since the girls don't need so many calories to keep themselves warm. Whether the deep litter is actually generating heat as well, I couldn't say. I don't have a compost thermometer, so I have no way of distinguishing the sources of the heat in the hoop house.
Given the overall cost of the hoop house project, it was important to me to pimp out the hoop house for as little money as possible. Most of the following tricks and accessories cost very little money. While some of these were doable largely by making use of fortuitous chance, I hope some of them at least will be useful to others who have or are considering a hoop house.
In the center of the hoop house I've place a truck bed storage box - one of those things that sit across the bed of a pickup truck and provide a lockable compartment akin to the trunk of a car. (The garbage can sitting on top of it holds the chicken feed safe from dripping condensation and rodents.) This one came with our beater pickup truck, but we didn't need it. I thought it would make a pretty good seat between beds. More importantly though I noticed that it was black and that it could hold water. Black things absorb solar warmth, and water has a high thermal mass. So I filled the bed box with as much water as it will hold (with some soap and salt added to make sure it doesn't become a breeding ground for mosquitoes). Now it's doing double duty as a bench and a heat sink. The other use I might want to turn it to one day is as a large vermicompost bin. I suspect it wouldn't be great for worms in the summer time, but I'm mulling it as a possibility for next fall and winter. That could provide a nice homegrown source of protein for the chickens next year.
My next trick is one I've used before in the garden - reflective material along the north side of the hoop house that maximizes the natural light the plants receive. This time I've added a cheap space blanket that I found at a 99-cents sale. I got one for each car and our emergency kit at home, plus one for the hoop house. Now I wish I'd gotten two for this project. It's highly reflective and it probably also acts as thermal insulation.
Then there are the low hoops over each growing bed. These were invaluable while the hoop project was still under way. They were the only protection the plants had from frost for a while there, before the sheeting went on the big hoops. Now the low hoops give a second layer of protection, keeping the temperature in the beds even warmer overnight. In fact, on sunny days I need to get out there and raise the plastic off the low hoops lest the plants get cooked. Fortunately, with the hens in the hoop house, daily maintenance is built into the schedule.
Predictably, before the house was completed and before the winter weather even got too severe, some rodents took up residence on the margins of the hoop house. There were plans to place 1/4-inch hardware cloth around the perimeter of the house at ground level. Our delay on that part of the construction allowed the mice, or voles, or whatever they are, to move in. It's still the plan to install the hardware cloth. In the meantime, I knocked together a trap box based on Rob's vole motel, but so far I haven't figured out what bait will snare them. Either that or the neophobia (fear of new things) common to many rodents has kept them safe. I know they've been through my box; the dirt tracked into either side confirms this. If the peanut butter bait still hasn't worked in another week, I'll try something else. So far my carrots don't seem to have taken any damage, at least not at the surface where I could spot it before harvest. Who knows what's going on underneath though.
Here's one I'm rather pleased with. I built myself a weeding/harvesting board with an extra cross piece that extends my reach across the beds quite effectively. This was a scrap piece of the 2x6 cedar wood that we used to construct the raised beds. I tricked it out with some risers and braces underneath so that it is stable on the edges of the beds and doesn't completely flatten the growing plants. The sitting board allows me to easily reach the far side of the beds. When I rest the cross piece on the sitting board and far edge of the bed, I can lean way out for wider access across the beds. I put some wood sealer on the boards, a useful measure given how humid the hoop house is.
Okay, more tricks. To use every bit of space that possibly can be used, and to eke out as much productivity as possible, I scrounged through the pile of stuff we've pulled out of construction site dumpsters and came up with a simple shelf. I hung it from the purlin on the north side of the hoop house. With the sun low in the sky from fall through early spring, the shelf doesn't cast a shadow on the raised bed below it, so no light lost to the growing space. Right now I'm only using the shelf to store oyster shell for the hens and a few other items. Come springtime, this shelf and others like it will increase my growing space. They will be ideal spots for vulnerable seedlings in trays, keeping them well out of reach of our unwelcome rodent guests.
Our hoop house has lighting too, which is for the benefit of the hens rather than the plants. We happened to have an extra fluorescent hanging lamp lying around in the basement, and it just so happens that the previous owner of our home ran electricity out to the shed. So rigging the lamp from the ridge pole of the hoop house and running an extension cord to the shed was no big deal. As I have done the previous two winters, I am lighting the hens with the help of a timer to keep them productive over the winter months. It took quite a few hours of lighting them at first to bring them back into laying. Right now we have mostly heritage breed hens, and they had all stopped laying for the winter season. Now that we're getting a decent number of eggs each day, I may try slowly cutting back the hours and/or removing one of the two bulbs to save on the electricity bill. My understanding is that it would require an enormous amount of lighting to make any difference to the growth of the plants. That's not something I'm interested in paying for. As far as I can see, the fact that the plants are practically in stasis is one of the main benefits of winter hoop house growing.
An indispensable accessory for the hoop house is the common broom. A pair of brooms helped us coax the plastic sheeting over the large hoops. It also allows me to gently push up the sheeting from the inside to coax accumulating rain and snow off the sheeting. I keep one in the hoop house at all times.
A not so cheap aspect of the hoop house are the multiple self-ventilating windows. I had intended to content myself with just one of the expensive piston openers when I spotted them on sale at Johnny's. Unfortunately, I didn't communicate this to my husband, who spotted the same sale and purchase two for me as an anniversary present. We decided to indulge ourselves and not return any of them for a refund. So our hoop house is going to be very well ventilated when my husband finishes installing them. The way these work is that the piston contains a temperature-sensitive fluid that expands as it warms and condenses as it cools. So as the temperature increases, the piston opens the window automatically, then closes automatically when the temperature drops. It sure is a nifty trick and I admit that it saves me the need to pay a lot of attention to what's going on in the hoop house. Still, even on sale, these things weren't cheap, and I would have contented myself with fewer of them under different circumstances.
The final feature I want to mention is one that I can't take a picture of. We built this hoop house and arranged the beds directly over the surplus heat dumping coils for our solar thermal array. We actually requested the placement and configuration of those coils with the hoop house project in mind. Right now we're not shunting any heat whatsoever to the coils, because it's wintertime, and we need every bit of heat we can collect from the solar array. So presently we have an unheated hoop house. But come the shoulder season in spring, when our heating demands go down in the house, we will be able to divert some of the heat from the array into the ground underneath the hoop house. The same could be true in the fall shoulder season as well. It remains to be seen whether or not this will provide any advantage. It may be that by the time we have excess heat to vent from the array, the hoop house will already be quite warm enough. There is an alternate heat venting system that we would use in that case.
I expect having the hoop house will change the growing routine around here quite a bit. I'll be able to start plants earlier in the year, and keep a small number of them carefully manicured in there year-round. I'm thinking about implementing some proper square-foot gardening in there to really max out the potential of covered beds. I'll need to learn how best to use the extra heating that should be available in spring and fall; an unusual set-up in hoop houses that have heating available.