Extending The Growing Season In Cold Climates

Hello!

So I plan to partition pieces of growable terrain, remove manually any snow cover, place a black fabric that heats up the soil by absorbing the sunlight in an attempt to thaw out the soil still frozen down to the frostline. After this happens, work the soil and plant seeds or seedlings started indoors and hardened. To help the seedlings along, replace the black fabric with a commercial white fabric that protects during the cool nights by shielding and maintaining a higher temperature and removing it during the day.

In the event of a killer frost (sometimes either in early June or early August), smudge fires (in barrels) that produce a lot of smoke can be used.

The growing season here is 60 - 90 days June to August, postal code J0R 1H0 in Canada, but I'm in the hilly country about 1000 feet altitude. We have a 6 month winter season.

Anyone using this or similar technique, please comment and mention the type of fabric used (could it be burlap?), the brand or other commercial product or even a home made cover?).  

George Mogil wrote:Hello!

So I plan to partition pieces of growable terrain, remove manually any snow cover, place a black fabric that heats up the soil by absorbing the sunlight in an attempt to thaw out the soil still frozen down to the frostline. After this happens, work the soil and plant seeds or seedlings started indoors and hardened. To help the seedlings along, replace the black fabric with a commercial white fabric that protects during the cool nights by shielding and maintaining a higher temperature and removing it during the day.

In the event of a killer frost (sometimes either in early June or early August), smudge fires (in barrels) that produce a lot of smoke can be used.

The growing season here is 60 - 90 days June to August, postal code J0R 1H0 in Canada, but I'm in the hilly country about 1000 feet altitude. We have a 6 month winter season.

Anyone using this or similar technique, please comment and mention the type of fabric used (could it be burlap?), the brand or other commercial product or even a home made cover?).  

I would use row covers instead of smudge fires in the event of a frost of the type you are talking about.  Smudge fire by definition would be incredibly polluting.  I'm trying to improve the environment, so that sounds like the opposite of what I'm trying to accomplish.

There are several techniques for pushing the zones or creating a microclimate.

If using the black fabric and then replacing that with white fabric works for you, please report back to let the forum know.

I like Trace's suggestion about using row covers rather than smudge posts.

Just about any sort of cover will work to keep frost off the plants.

Hi George,
You might look into Eliot Coleman's work... specifically his book 4-season Harvest. While not quite as cold as you, he has had a lot of success extending the seasons by using row covers and cheap greenhouses and changing what crops he was growing.

We are in a very similar environment in a cold valley in Idaho. We use hugel beds (apx. 2 feet tall) and they heat up quicker in spring than the rest of the ground. Right now the beds are almost clear of snow and we still have 6-12" of snowpack on the ground. We don't use plastic in our garden mostly because I don't want plastic leaching anything into the soil. I have enough plasticizers in my body.

In the spring and late summer we put garden cloth over a framework above the beds to keep the warmth in. It's good for those random frost killer nights in June and August. This is a pain if you have a lot of garden, so I tend to put the most frost sensitive plants in the same bed and concentrate on covering those. The rest I'm working on landracing varieties that are somewhat frost tolerant.

I wouldn't dare use smudge fires in August around here. Wildfire danger is usually in the very high/extreme category at this time. I don't like the idea of adding pollution to the air in any case.

Bonjour mon ami! We have very similar growing seasons: my postal code is K0J2B0

I do not use the fabric, but if I could recommend perhaps a greenhouse would do the trick and this could not only thaw the ground in spring but extend your season in the fall. We are currently experimenting with this. We purchased a greenhouse from Planta Greenhouses and we dug out a 4 ft foundation in which we plan to install a rocket mass heater only the pipes will run underground and heat the surrounding soil. All of this likely sounds crazy, but I promise to update you when it is complete and wether or not is it worth the time and effort in our climate / growing zone.

Please update me on your success with the black fabric cover. If this is successful I would like to adopt this strategy for thawing my outdoor garden beds

Having lived in northern MN for 4 years, I would try a high tunnel.  

Hi George, we have the same short season as you. A greenhouse is your best bet, and definitely check out Elliot Coleman as mentioned, he basically put a greenhouse in a greenhouse to trap more heat. Adding an RMH to a greenhouse would be worth the effort if you have the time and skill. Here is a link to one such build, lots of details and photos. http://www.quesehrafarm.com/2016/04/20/building-our-greenhouse-rocket-mass-heater/
You mentioned “place a black fabric that heats up the soil by absorbing the sunlight in an attempt to thaw out the soil still frozen down to the frostline” and the problem with that is it only works (barely) with raised beds. Otherwise you are trying to heat soil surrounded by frozen ground and it’s a fool’s errand essentially. As fast as you heat a spot, that heat gets sucked away. Even with raised beds it’s slow progress unless you have insulation below them somehow. We keep r10 foamboard on the north side of ours, and even with mini hoop covers of poly we only gain a couple weeks.
The ultimate trick is to to keep an area from ever freezing during winter, then using the black fabric in spring to warm the (already not frozen) soil. We have successfully used 12” thick EPS insulation which is about r45. Placed on the ground before it freezes in the fall, and of course covering a bigger area than you need since the perimeter will still freeze inward. It comes in 4x8 pieces and gets covered with poly or a tarp. Also consider building a Walipini with perimeter insulation and maybe even earth tubes underneath. If you have or can create a south facing slope, even better!

There are several potential methods.  The black fabric followed by white is interesting, but most areas can receive strong winds.  For example, my home is located on a bench higher than most hills west of me.  We always laugh at high wind warnings unless they exceed 45 mph.  Even a 30 mph wind, however will move a lot of fabric cover unless it is anchored.

For late frosts, a floating row cover anchored over a row or swath of plants can be supplemented by using recycled milk or water jugs.  So long as the jug does not contain toxic materials, it can be used.  I have successfully used this for decades for sensitive squash, melon and other plants.  For heavy protection, place two jugs on the NW and NE sides of each plant.  They generally need clear space from weeds and the jugs sitting on soil tend to assist there as well.  The floating row cover helps to keep insects away as well as deer (deer really fear any white moving material - kicks in their flight instincts).  

I also used sprinklers one year where we had frost every month. Each morning with frost, I would open the valve and blow accumulated ice from the hose then hook up the sprinklers and soak the plants before the sun rose.  That way, you cover the generally coldest time of the night frost and water plants for the day at a time when the water is best placed. Water releases a major amount of heat as it cools, if it is on plants, it tends to warm the vegetation slowly and the cells do not rupture as much, if at all.

Best system I ever saw was a geodesic greenhouse in VT.  They installed a circular pool in the center and planted the periphery. Fish were raised in the pool (trout in winter and catfish in summer) while the water kept the growing area warm enough to grow Cruciferous vegetables all winter while cold-sensitive plants were able to extend their growing season significantly.  If one wants to be even more efficient, plant bags of peat moss with drip systems over the pool.  I would suggest a wheel axle in the center to allow a balcony or two for tending/harvest.  A geodesic dome should have a central pier to hold the center down anyway.  With cold weather dome covers above the hanging plants, some really interesting fruits and vegetables could be grown and it would make for a relaxing area to inhale the extra oxygen from the plants while resting.

Hi George,

I live in south-central Alaska and have been trying to find ways to extend my growing season for years. Unfortunately, every year is different so what worked one year won't always work the next. I've tried black plastic, but it didn't work well for me. It seemed to shade the snow I was trying to melt. Clear plastic worked better,  but there is only so much that can be done while the sun is still low on the horizon.  I'm just above 60 degrees north latitude and  it seems like it isn't until early April that melting really starts to happen. Even then, the ground is too wet to work and too cold for germination. I still have about 3 or 4 feet of snow, so it may be May before I get to see my beds.

In years when I can get a snowblower into the garden, I like to remove as much of the snow as I can without tearing up my slightly raised beds. They're frozen fairly solid, so no worries about compaction. I then sprinkle wood ashes on the beds to darken the remaining snow. This melts the snow quickly, assuming you don't get a late spring snow that covers the ashes. Once the bed is exposed, the dark, moist soil is still too cold and wet for germination, but its weeks ahead of the non-treated spots. A low tunnel over the beds has helped me in the past.

It's not my favorite thing to do, but I also grow potatoes in plastic growbags placed on a large gravel area the previous owners created. I get good yields and the soil warms up quicker than does the ground. Plus, I don't have to invert my soil layers hilling or digging up the spuds. Crop selection is critical for cold-climate gardening. Long day onions, hard neck garlic, brassica crops, greens, potatoes, some kitchen herbs, peas, and the most amazing carrots and beets I've ever had make up the majority of my outdoor crops.

I have a small greenhouse with in-grpunds beds. I put cold hardy greens in there a couple weeks ago. I know it's cheating, but I also have a heater in there to keep it above freezing at night. I'm tired of grocery store greens and the overnight warmth breaks the momentum of the cold. I can generally get the greenhouse 20-30 degrees Fahrenheit warmer than outside temps during the day. I can't recommend enough a high tunnel or greenhouse. They not only help extend the season,  they add growing degree days to those heat-loving crops like summer squash and tomatoes.

I start most of my crops inside well before the snow melts. I put LED growlights under the kitchen cabinets and have taken over my wife's kitchen.  Once the seeds germinate, the seedlings goes out to the greenhouse to grow their sun leaves. Some crops just take too long to not start early. Things like leeks, tomatoes, and hard squashes have a hard time maturing if I don't start them early and/or we have a cool wet summer. I plant a lot knowing some crops won't perform.

Worst case scenario, have some sheets or row cover cloth on stand-by if you get bedeviled by a June or August frost. They suck, but picking frost tolerant crops helps that be less of a concern.

Good luck,
Ben

Ben Polley wrote:  I also grow potatoes in plastic growbags

We use 5 gallon buckets which are essential to us for so many things! Drywall outfits give them away and we may have close to a hundred by now. Painted black, they make great early season planting containers for many things including potatoes. Easy to relocate by the handle or with a hand truck/dolly, easy to cover, easy to dump out. They even make great worm farms. The only downside is more watering, but we found a couple inches of wood chips in the bottom helps. We also plant potatoes in raised beds, but the buckets give us earlier ones.

I like the "greenhouse inside of a greenhouse" idea as dead air is a cheap source of insulation. As you add the second layer of plastic over the greenhouse, you could also place regular insulation on the north [cold] side, all the way up to the top or part way up.
Large plastic barrels painted black also provide a thermal mass that would keep plants warm for longer. If I could afford it, I would partially bury the greenhouse in the soil or add soil on the cold wall. I would try this first as it is the cheapest and it would also work *with* the rocket stove idea.
If you still do not get enough heat with these passive heat ideas, you could add a rocket stove, as these ideas will work together. The rocket stove, by itself, would solve all your problems but 1/ it would gobble precious real estate  in a hoop house and 2/ require more talent, hard work and money. You would want the heat to be well away from the plastic cover/s.
So that is why I'd want to go with passive heating first.

Painting the buckets black helps a lot as most are white to start with, at least the drywall mud ones we get. An alternative would be wrapping them in landscape fabric. Things like squash and tomatoes thrive on warm soil and can tolerate cool air better than cool soil it seems. Once you are north of the Canadian border it makes sense to have a solid insulated wall on the north side of a greenhouse because there’s not much sunlight coming from that side anyway. If it’s white on the inside it reflects a lot of light back at the plants. We have two 55 gallon drums full of water in ours which moderates the temperatures a bit.

OOOOpppppss! I posted this in the 'Safe Containers' forum, but left it there.

I've tried some Winter-Sown veggies this year in Quart Milk Jugs, cut about 4" up from the bottom and left as is on one side to act as a 'hinge'.

These are all brasicas, cold crops, so the extension is that they grow when the seeds feel the temps are right and this gives you at least 2-3 weeks extra. IF you wait to buy plants that extension might be as much as 5-8 weeks!

I live in East Central Indiana and weather has been very cold temps overnight especially, so they should have gotten enough, in three weeks of of the cold period, even if I got them out late. And it seems to have worked!

I looked down the spout today and I actually see green things growing in there. Of course - some - of that may be weeds, but I'm happy to see that some of the seeds survived and are taking off. I'll just let them grow until time to transplant.

Niki Jabbour has written another nice book about season extensions:
https://www.amazon.ca/Growing-Under-Cover-Techniques-Weather-Resistant/dp/1635861314/ref=sr_1_1

She is (and I am too) in zone 5b-6a in Nova Scotia, less challenging than the Laurentians where you are, admittedly. I made a little greenhouse out of an old swingset, and suspended row cover over the salad greens - if you figure out what and when to plant them so they're strong enough through the coldest weather. I've had salads at Christmas and Easter, if little between those dates, but sprouts or shoots grown indoors can fill that gap. A tunnel or greenhouse with row cover inside (as Eliot Coleman mentions) will boost your zone by 2 or 3. Lots of tomatoes are grown commercially in greenhouses in Nova Scotia.

Hi George, I recently saw a book in the library by Mike Oehler on Earth Sheltered Solar Greenhouses which has some interesting ideas if you are somewhat handy at building and have land on a slope.  It uses a cold sink method to pull cold air down away from where the growing area is keeping it warmer up top. If you have cardboard you might make 3 sided shelter around your plants with several thicknesses and use row covers or recycled window frames/panes to let sunlight through on the south/west side. Maybe the cardboard sides can be cut on a slant like a cold frame. Not sure if covering the cardboard with plastic would be to your liking but it might extend the life of the cardboard  somewhat thru rain/snow.  Back up the cardboard sides with hay bales or dirt or something to hold in heat.

If you want to quickly melt the snow with zero pollution, sprinkle ash. It melts the snow fast and fertilises the soil. Just do not overdo it, since ash is alcalic.

I would build a wall around the beds and cover the beds with a frost blanket. You will not change the temp drastically, but every bit counts.

Also, a sool rich in microbial action melts much faster than a tilled, packed soil. The difference can be striking. See this pic.