Container Gardening Conundrums

Dear Joel,

We live in the Rocky Mountains — zone 4– at an altitude of 7800 feet. We have a short, unpredictable growing season and a large population of deer and rabbits. We currently have a container garden in a small “greenhouse” (white tarps over a frame) placed against a southern wall of our home, which has produced mediocre results. What advice can you offer on suitable heirloom varieties for our area?

-Kate Hamilton

Kate-

Oh, this one is out of my league. I’d defer to to Seeds of Change or Seed Savers — there are a host of good seed folks out there who know climatological acclimation of numerous varieties. We buy most of our seeds from Southern Exposure Seed Exchange, located just 50 miles away from us, because all their varieties are grown and selected for mid-Atlantic adaptation.

I’m sure a similar seed bank exists in your area. If you have trouble locating it, check with your nearest Permaculture support group. The Permaculture network maintains databases of seeds — they concentrate on perennials, but they certainly do plenty with annuals as well.

I’m thinking your white tarps may be too opaque. You don’t say in the question whether your poor results are due to temperature or sunlight, but a white tarp would affect both negatively. Get some clearer plastic and see if that won’t help by both upgrading the temperature and increasing the UV penetration. Container gardening has really come along with the urban farming tsunami and plenty of material exists out there to help you along with that.

One of the big problems with the container gardening is that you don’t have a big enough heat sink to stabilize temperatures between day and night. You may need to think about adding some thermal mass, even if it’s 55 gallon drums painted black and filled with water to set your plants on. The barrels absorb daytime heat and slowly release it all night. Plants do not like temperature extremes, so anything you can do to ameliorate these would be beneficial.