Coldframe/hoophouse question/confusion

kroach001February 17, 2013

Hi All.
I'm hoping some of you that have grown in cold frames and/or hoophouses can shed some light on this for me.

I just can't wrap my head around how a cold frame or hoop house helps you grow things over the winter. I get how it warms it up nicely during the day. Got that. But it won't hold in enough heat at night to keep common cold crops from dying. Temps inside are maybe 1-3 degrees above what they are outside overnight. They may have protection from direct frost, but effectively none against temperatures. I've tried lettuce and broccoli that both died in low 20's temps. I have one friend that has a cold frame, but they bring their plants in the house if its going to be really cold overnight. But I know people say they grow/keep things in there all winter. Over the winter we commonly get overnight lows in the teens and occasionally in the single digits.

If someone could help explain how it keeps plants from dying from extreme cold overnight, I'd love to understand! People say they grow with these methods over the winter and it bugs that I can't seem to understand how it works.


Thank you for reporting this comment. Undo

I don't know about hoop houses. But one of the keys to successful use of a coldframe is growing very cold hardy/cold tolerant plant varieties, choosing vegetables that thrive in or tolerate the cold. Another critical point in using a coldframe is to start your plants early enough before cold weather arrives.

Cold frames often need to be "insulated" with hay or straw piled around them, making berms or stacking hay along cold frame sides and covering the top of the frame with blankets or straw at night to extend the growing season. Some people use heavy black plastic bags filled with leaves to insulate. Some cold frames are even sunk into the ground somewhat. Your zone conditions dictate the type and amount of additional protection needed.

Hardy perennials don't work well in a cold frame, but some annuals can get a faster start in a coldframe.

    Bookmark   February 18, 2013 at 10:20AM
Thank you for reporting this comment. Undo

For hoop or coldframes some users bury a thick layer of fresh manure which is covered with soil for more ground heat, or place large drums of water for heat storage from the sun which helps hold the temp down over the nighttime inside, string lights for added heat during cold days and nights. Even black plastic on the soil should add to the daytime heat in the soil.

    Bookmark   February 22, 2013 at 4:28PM
Thank you for reporting this comment. Undo
livelydirt(Zn 4, Lively, ON)

Get a copy of Eliot Coleman's 'The Winter Harvest Handbook' and treat it like your garden Bible. In Zone 6, you can effectively become a zone 9 following Coleman's advice.

Here is a link that might be useful: Lively Dirt - The Garden Blog

1 Like    Bookmark   March 1, 2013 at 11:09PM
Thank you for reporting this comment. Undo
jrslick (North Central Kansas, Zone 5B)

You grow cold hardy crops. If you are expecting to grow tomatoes or cucumbers, you will fail. You can grow lettuce, kale, swiss chard, bok choy, napa cabbage, cilantro, spinach, green onions, arugula, mustard, carrots, many other asian greens. Many of these crops will freeze and thaw out and keep growing. You don't really "Grow" during the winter, it is more you grow before it gets too cold and then you "Harvest" during the winter. The plants do grow, but due to the low light levels, the grow at a very slow rate.

How big are your cold frames? Size does matter. If you have a very small high tunnel, it won't hold enough heat to be successful. I have 6 high tunnels and grow produce year around. We also use row cover with low tunnels inside our high tunnels.

If you read the winter harvest book, you will be in business.

1 Like    Bookmark   March 2, 2013 at 9:17AM
Thank you for reporting this comment. Undo
gardnpondr(Zone 8)

I have a friend in MI. that uses hoop houses and I would dearly love to do this in the wintertime as well. I need to pick her brain. :-)

    Bookmark   October 7, 2014 at 10:24PM
Thank you for reporting this comment. Undo

Also check out Niki Jabour's book she's up in Canada, it's totally cool. This is my first year trying it out but I'm in Wisconsin and am trying it out for the first time. I'm going to document how long each type lives. Here's the hoop house and current state.

Here is a link that might be useful: Hoop house creation

    Bookmark   October 21, 2014 at 11:31PM
Thank you for reporting this comment. Undo
gardnpondr(Zone 8)

I just got the winter harvest handbook from the library today. Eliot Coleman. going to check it out and see if I can use some of his info in South Ms.

    Bookmark   October 22, 2014 at 12:35AM
Thank you for reporting this comment. Undo

First, here in NH, the ground inside my high tunnel doesn't freeze even though night time temps can be below zero. The short day period of plant dormancy ended mid-February. A local market grower said a few weeks ago that he had started hardy greens inside for April harvest and expected to plant peas March 1. We still have 2-3 feet of snow. I have not looked inside my high tunnel due to rodent damage last fall. I suspect they are in there sunbathing. I should have been able to pick spinach etc all winter but the last I saw of my spinach patch, hlf of it was browsed to the ground. I had some red romaine growing in a large flower pot and was able to stick a tomato cage in the pot, then wrap with a couple of layers of Agribon 19. I had some arugala and chard plus a bit of spinach so met my goal of having a salad for Christmas. But, if I had put the effort into it, I should be harvesting mixed greens right now. I can get them at my local winter farmers market. I recently bought Four Season Farm Gardener's Cookbook by B. Damrosch and Elliot Coleman. The first half is all growing instructions. If you "like" or "friend" local market farmers, you might also get some tips as to when and what they are planting. With higher temps (sap is running!) next week, I should have my husband plow a path to the high tunnel and get gardening again.

1 Like    Bookmark   March 6, 2015 at 6:06AM
Thank you for reporting this comment. Undo

A big help for me is that I put my lettuce garden right up to my house (which is brick) The heat that the bricks get from the sun during the day helps keep the soil and plants warmer in the hoop house. Also, if I know it's going to be much colder than normal, I leave the plastic over my hoop house all day and let it warm up so it has reserves of heat at night.

    Bookmark   March 6, 2015 at 8:23AM
Thank you for reporting this comment. Undo

btw it's only 6mm plastic but on a sunny day it can heat up even in winter. Today it is about 21 degrees at almost noon but it's 78 inside the high tunnel.

1 Like    Bookmark   March 6, 2015 at 8:53AM
Sign Up to comment
More Discussions
Help make my backyard not smell
This may not be the right forum, Please let me know...
cold fall in MN crop report
It got down to 11 degrees here Tuesday morning so when...
Evergreen shedding?
I have this beautiful expensive evergreen for a year....
Help with my cilantro microgreens
Please excuse me as I couldn't find a forum just for...
How to keep this plant
Hi all, I am new in NZ and absolutely know nothing...
People viewed this after searching for:
© 2015 Houzz Inc. Houzz® The new way to design your home™