Experiment Extending Short Season

The growing season in my neck of the woods is roughly 90 days and I've been experimenting with ways to extend the season without using structures like green houses, cold frames, or row covers.

Last year I experimented with covering the garden beds with plastic with the thinking that if I could prevent the ground from freezing then it would come up to temperature faster in the spring time.

This year I'm testing a different approach. Instead of covering the beds, I will try accelerating the spring melt so that I can get solar energy into the soil as early as possible.

I will be using spent coffee grounds as my solar energy absorption and snow melting medium.

So yesterday I went to the garden and found it still under a few feet of snow. I got out the shovel and located the pathways which I dug out so that I knew where the grounds needed to be spread.

I then sprinkled the beds with a thin layer of the coffee grounds. Too think and they might form an insulating crust which isn't what I want. My intention is to have each ground being like a small solar themal battery that will melt it's way down through the pack into the bed below.

So here are a few pictures after I was done and I'll post some more as time goes by.

Woodstove ashes might work as well, especially if it's got some bits of charcoal in it - and also good for the soil!

My reasoning behind not using plastic over this winter was simply that I used plastic and I'd like to get away from that if possible.

The coffee grounds are a much more environmentally sustainable option seeing as I'm diverting an industrial waste stream which also happens to be a high quality Nitrogen source rich in minerals. It is also PH neutral.

There is roughly 500 sq ft of garden beds and I used a full sized garbage can full of grounds to get the coverage shown in the photos.

I have another full garbage can waiting to go for a second application.

This project has diverted the entire coffee waste from a coffee shop that operates 18 hours a day, every day of the week.

I have extended my growing season by growing varieties that are more cold tolerant... Within each species I have found wide variations in how much cold they can tolerate, and how well they grow in cooler weather. I've ended up developing my own varieties that are descended from the most cold hardy and/or frost tolerant ancestors.

Nice idea changing the albedo of the surface. If you have wood ashes try those too - they will add nutrients and some of the ions in there will act like salt-grit and dissolve/melt the snow.

Joseph is also on the right lines... selecting for shorter seasons/cold hardiness is likely to have a substantial impact on yield over the longer term... probably more than you can get by extending the growing season by a day or two.

The best way to accomplish your goal is to deep mulch in the fall to start, deep leaves to insulate the ground so the frost doesn't go as deep until the snow has enough depth to insulate .
In the spring you want to make a solar collector. Dark colour covered by a transparent sheet. Go ahead and spread your grounds (or ashes, or compost) on the snow but then cover that with plastic sheet. Once the snow is melted you probably want to pull your mulch back to expose the soil to the sun and replace the sheet.
This will give you the best heat gain during the day.

You'll still loose the heat at night unless your cover has better insulation like old windows or you cover with some sort of insulating blanket at night.

Plant and pull the mulch back a month or two later when you're trying to reduce evaporation from the soil.

Well I went to the site yesterday to check it out after we had some more snow. I brought with me more coffee grounds as I was expecting my previous work to be buried. Here are some pictures of what I found.

I was particularly impressed with the fact that the garden beds that I sprinkled used coffee grounds on are completely clear of snow, even after the covering we got the previous day. Meanwhile, the areas around the garden beds that I didn't touch are still under quite a few inches.

I noticed that my original application of used coffee grounds missed a few spots and went over in others. The area near the compost heap is a good example of where I went over. Before I left, I applied used coffee grounds to where I missed the first time, and also over the beds in general.