Season Extension Techniques: Cheap and Dirty Options
Sharon July 21st, 2009
I want a greenhouse. No, I want a glasshouse, a true British style Orangerie and succession houses (and, of course, the extensive grounds to accompany it, and the private fortune, as long as we’re dreaming). I dream of wandering in winter into tropical glory, and plucking ripe grapefruit from the trees for my breakfast, while the scent of jasmine permeates my senses.
Ok, revisiting *this* planet, the one I actually live on, and the one that’s already suffering because crazy people want to live in the tropics when they don’t, what I’d really like is an attached greenhouse on the cement slab that comes off my kitchen. But the slab would have to be insulated and we’d have to find the money and the time to build it, which may happen eventually, but has not yet done so. What I’d grow there would be cool season vegetables and seedlings in the spring.
Or I’d like a hoop house. This is more viable, but requires some infrastructure work we haven’t gotten to yet. My goal there would be to keep things over the winter in large beds, and maybe eventually go back into the CSA business, this time in winter. But I don’t have that either.
I mention all these things I *don’t* have because I think it is important to realize how even in many quite cold climates, it is possible to use very simple, very low cost strategies to extend your season. Despite all these things that I don’t have, let me tell you what I do have:
- I have fresh green vegetables grown by us from March to December or January, every single year. This is in upstate NY, where our winter lows hit -30. First frost is early October, last is usually late May.
- I overwinter produce every single year, including both hardy root crops and greens like kale, spinach, leeks, etc…
- I have two lemon, one keffir lime and one orange tree, a fig and a pomegranete, along with many smaller tender plants.
- I have fresh things of high nutritional value to eat all year round, produced here.
- I start virtually every single one of my seedlings here, in the house, and use only a couple of hanging lights. I use no lights in overwintering my tender plants.
- I have nursery beds for starting hundreds of perennials, fruits trees and berries over the winter.
I mention all this to give people a sense of what is possible with very little effort or input. My tools for doing this include:
- Two “pop up” greenhouses (ie, they can be set on top of a raised bed or flat crops, one little stand up greenhouse (ie, a plastic cover over a plant rack that sits on a porch.
- Self-watering containers on a poorly insulated sun porch
- some greenhouse plastic and old window frames and some floating row covers
- Lotsa mulch and bales of hay
- My unheated, uninsulated garage
- A couple of south facing windows
- Willingness to experiment
I’ll talk more next week about growing food indoors during the winter, and making use of your home – this week I want to talk about simple structures to extend the season outside the house. Now obviously, this won’t work the same for everyone – someone, for example, who lives in a much colder climate may not be able to overwinter anything – but they might be able to use the same techniques to get a month or two more growing season. In other places, you could do most of what I do outside without any of these things. But the techniques themselves should be available for you to consider and evaluate.
So what are some of these? Well, the first one I can think of is mulch – yes, plain old mulch. If you live in a cold climate, where the ground freezes, insulating the ground so that it doesn’t freeze, or doesn’t freeze as deeply can keep plants going a surprisingly long time. Deep mulch on dormant plants marginal or not usually perennial in your climate, for example, can allow you to grow many perennial plants you didn’t think you could grow. Eric Toensmeier grows hardy bananas in Massachusetts with deep mulch (think a bale of straw or two). Less extreme, I’ve overwintered rosemary outside in good years and maintained a Maypop. Figs can be overwintered with deep enough mulch (ie, enough to cover the whole plant in dormancy, wrapped well to keep the mulch on in winter winds. Mulch is often underrated – your carrots, your beets will survive, if not a whole winter, a surprisingly long time with enough mulch. This only works with plants that are either perennial or root crops, generally – eventually lack of light will kill everything else, but that covers a surprisingly large number of items.
Next up – the crazy easy solutions – cut the bottom off a plastic milk jug (dug out of someone’s recycling bin, of course) and put it over a favored plant. Add a few stakes and a piece of plastic sheeting or a floating row cover, and enjoy a month’s extra time with your greens. Stuff will also do better in sheltered spots or microclimates – that place along the edge of the driveway that is too hot for much of anything in summer will be just the spot for the stuff you want to overwinter.
There are lots of products out there to help you, including regular and fleecy row covers, cloches, and there are plenty of little greenhousey things you can buy. These can be helpful, but make sure you are getting good quality stuff – you want heavy duty plastics designed to tolerate sunlight and snowload (if that’s relevant), and not to wear out, or row covers with long term lifespans. Using plastics and petroleum based solutions can be acceptable, if you are getting a decent return out of them and they are the best available option – but using cheap plastics and replacing them every year is worse in many cases than transporting food from warmer places, so choose wisely. I like the stuff sold by Johnny’s Selected Seeds www.johnnyseeds.com for season extension.
The cold frame is a great tool, and my favorite model is the easiest to build – the hay bale cold frame. TAke four or six or however many bales of last year’s hay or straw (that has been kept dry). Lay out the bales in a rectangle around an existing bed, or fill them halfway up with soil and compost. Take a window or old glass door (do not use anything that might have old lead paint on it, ever) that fits over the top, and cover it up. Tah dah! This kind of frame almost never overheats, because the bales don’t fit together tightly enough to prevent air from being vented, but the bales also insulate the soil well enough that things overwinter beautifully. And in the spring, after a winter of sitting there, all the mulch is nicely decomposing and makes great organic material for your garden, and is already right where you want it.
This trick is tough if you have to put it in the front yard of your suburban neighborhood, so you might want to build a cold frame that looks prettier, like this: http://www.doityourself.com/stry/oldwindowuses
You can also use a hotbed – this is a cold frame, filled with uncomposted manure, mixed with high carbon material, where the heat of composting keeps a cold frame or open bed warmer than it would be otherwise. The composting material is covered with a layer of soil to keep the plants from being cooked, and the hotbed provides warm soil in cold times. Because the heat of decomposition gradually declines, you will want to use this for short term, rather than long term warmth, to keep something going longer or to get a fast maturing crop ready.
There are lots of cheap greenhouse plans out there – I’ve not enough experience to know which are good, but I do have some concern with many of them in places that experience heavy snow loads – I’ve seen too many collapsed hoophouses and plastic greenhouses around here, and all are too expensive and resource intensive to be used for only one season. This design http://www.kountrylife.com/articles/art1.htm seems sturdier than some of the cheap options I’ve seen (note, I am *not* advocating that you use their resource intensive strategy of electric heat (ugh!) and lights, just that I think the design is a bit better than some cheap options I’ve seen) but again, make sure you are doing something that will last, unless you are using all used and scavenged materials that would otherwise be landfilled. I don’t want to see a lot of people investing time and money in new 6 mil plastic and concrete, only to waste them and their embodied energy.
If you can afford a serious greenhouse, well, I’m jealous
. There are a lot of options out there, from simple hoophouses to serious glasshouses that really do look like the Restoration era glasshouses of my dreams
. I’ll cover greenhouse options next week in a separate post. This is about the cheap and dirty options – ones that get you a lot of food.
Sharon