The cold frame is best if you can bury the bottom of it slightly below the ground level to let the earth add to the insulation.

I have a cheapy one that I bought. I transplanted some turnips and beets into it last year mid winter and also grew some spinach. I was impressed. Going to sow some beets and turnips in it soon and see how they do over the winter.

Thank CataRose,
Yes, CF is very handy to start some seeds outside. It can help seeds germinate in shorter time.

I am putting my CF on level ground. I might insulate the walls from inside reduce heat loss. It is also a shelter for potted tomato and similar seedlings early in the season to prevent stunt. As I said before, it is the next best thing to small unheated greenhouse.

I will also try growing some cool crops, to experiment,

I think you can probably try a variety of different methods for different times. I will say with the Wall-O-Waters, one thing I appreciate is that they do not need to be vented. My season is short (05/15-10/15) and I generally can put tomatoes and family in WOW starting in April. I do not do it with all of the plants but this gives me a good start on the heirlooms that take more time. They also protect my plants from the fierce spring winds. Definitely do comparison shopping as I have seen wide variations in pricing. I think that I have gotten a pack of 3 for under $10 at Wal-Mart.

I like low tunnels too for extending the season. I am not as found of them in the winter though. The plants are warm inside but the gardener outside of them is cold which is why I hope for a hoophouse or greenhouse someday , to give me some protection from the elements too.

For the low tunnels, I have liked the perforated plastic linked below. I have used this early in the season to help heat lovers get a good start and you may find it useful in your climate. I intend to order more next year to use with sweet potatoes, cucumbers and okra to get them going a little quicker.

Here is a link that might be useful: Grow-therm perforated plastic

I've been using coldframes for a few years and this year I'm up to 4 of them. I also added a few low tunnels recently. It probably gets colder here in the cold months than the PNW. The first year I tried using gallon jugs with dark food coloring added to the water. They heated up nicely and moderated temperatures overnight but I gave up using them because they took up too much space. Since then I've been using Christmas lights (the old school type not LEDs). Last year I used the lights sparingly however this year I've been using them almost every night largely due to the fact that I started most things from seed in 2nd week of October and wanted the plants to get off to a good start. Also I picked up some sleeping bags from craigslist that get thrown over the tops in really cold weather. Also I bury my frames some and then pile leaves, straw and or wood chips almost up to the top of the frames.

The biggest concern is toasting the plants as the temperatures inside can easily soar well over 120 in a short time in the Colorado sunshine. Pretty much anytime it's over 35 F the frames need to be open at least an inch. Most days I leave them wide open. There is a need to check the weather forecast almost every day. When in doubt definitely ventilate.

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I have been interested in this topic since I discovered the Eliot Coleman books (he market gardens in Maine). The first thing is getting away from the old gardening practices of waiting until Memorial Day to plant here in NH and giving up in early September. I already knew that some vegetables like parsnips can stay in the ground all winter to harvest as soon as the ground thaws. So, I suggest doing some easy things first.

- a late planting of spinach can also winter over. I've had some survive without protection thru an almost snowless winter to start growing early in the spring

- carrots can stay in the ground with a covering of straw. I'm going to try the same with beets this winter (just bought the straw this week. One bale is $10 but goes pretty far.

- figure out what's worth protecting from a first, light frost. We typically have some great warm weather after a mid-Sept light frost. We use a portable low tunnel to protect a late planting of bush beans. They were in flower mid-Sept and just beginning to form little pods. The low tunnel provided enough protection to survive for another couple of weeks. The low tunnel is covered with Agribon.

- Somewhere I read that spinach is day length sensitive. Once I started planting spinach in early April, I got great harvests. If I waited until May, plants bolted. Size of harvest is also affected by fertility. When I skipped the spring application of composted horse manure, it looked like harvest was fine but a second bed planted slightly later after compost was added had much bigger plants.

- My husband built a wood-framed high tunnel in 2012 in time for me to sow some cold hardy plants. We had spinach all winter plus some beets but the lettuce varieties I planted weren't hardier varieties and didn't survive the first hard frost. This year the high tunnel was the location of my healthiest tomato plants while the ones outside suffered greatly from a cold wet spring. I suspect most of the disease problem was because soil was unmulched. There was no sign of disease in the plants inside the HT. Unfortunately, although the plants in the HT survived into late October, the cold nights have resulted in blah tasting tomatoes. So, it wasn't worth extending the season for tomatoes. In 2012 I had one hill of late zucchini in the HT. It may have only extended the season a couple of weeks. Did not put zucchini in the HT this year and regret not doing so. Outside zucchini got diseased. First time ever I have lost all zucchini plants early in the season.

- the flavor of kale and chard improves in cold weather and they can stand some frosts. Kale isn't popular at my house but if you like it, consider switching from lettuce salads to kale salads to extend your "salad" season.

A few other things I forgot to input. If you're going to build a cold frame then it's best to buy redwood or cedar which are a bit more pricey though not totally necessary. I always treat my wood with tung oil and after that penetrates which takes close to a week I coat the lower half of the wood (the portion contacting the soil) with paraffin wax.

Starting building another low tunnel today this one is with EMT tubing. I bought the bender from hoopbenders.net Just finished bending 4 pieces which wasn't all that difficult and look pretty unifrom. The price of the bender wasn't too bad I think it was $58. with shipping.

Thanks gicore

I am building my cold frame with cedar lumber. I will use your suggestion to treat it as you have said. Tube bender can be handy. I am going to check with my nephew. I think he might have one. What size EMT are you using , 1/2" or 3/4"? I think that 3/4" should be ok.

Can you post a picture after you have finished it?

I'm using 3/4" EMT. I figure the few extra dollars is worth it with the occasional heavy snows we get.

The basic plan is setting the hoops about 2 feet apart. I'm using 2 foot 3/8" rebar as posts to set the hoops into. Just ordered some greenhouse film online 12' x 55'. Will probably secure the film back (north side) with bricks/soil. The ends will probably be cinched together. The front side will either also be secured like the back or might use 2 1"x3" boards screwed together with the film in between so that it can be rolled open.

I extend the season solely with row covers and packing root vegetables in hay. Still in the garden and looking good despite one night below 20 are several types of fall/winter lettuces, spinach, escaroles, endives, beets, carrots, turnips, kale, collards, mizuna, and the savoy cabbges which can handle temps below 10 and which I harvest in Dec. and Jan.

I could build a little greenhouse, but it's not worth the trouble and expense considering how easy it is to just do what I do.

I took one of my raised beds, made a 4X7 cold frame .
Did this last fall, havent had time to really do it justice, however it is doing fine , especially now that I converted it to SFG.

Thanks lacey and japus

Japus ... that is a nice one. The one I am building is 3' x 6'.

I have built and used CF, in the past. It is very practical to germinate and shelter plants at cold nights. I will take pictures when I have finished it.

lacey ... I have never used row covers. Mainly I don't plant anything in long rows but in small raised beds.

I learned this year you can buy EMT conduit on sale for around $1.50 each. 10 per 50 foot bed is $15. You can bend them pretty fine with your foot and not spring for a bender. Then get 10 -12 foot wide row cover and 10-12 foot wide film to go over for more heat. I am short and I can put these over one bed with the path included in it and then monkey walk along but some people would have to crawl or sit on a garden scoot.
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inside one
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before row cover is on.

Thanks little-minnie for the idea and the demonstrations.
I think EMT (1/2" ?) is better than PVC that I have used before.

But I have a question about the material of those row covers. IF THEY ARE NOT AIR and WATER TIGHT, HOW CAN THEY PROTECT PLANTS FROM COLD and COLD WINDS ?

But the bending EMT is a good idea. It can be incorporated into hoops and low tunnels too.
Thanks

"I have never used row covers. Mainly I don't plant anything in long rows but in small raised beds."

I don't plant in long rows either. I have a permanent bed, no till garden with beds about 4 feet wide. Row covers come in 5 ft and 10 ft widths, usually, and work great in beds.

Row covers will give some protection. My opinion would be that it varies depending on local conditions such as wind, soil temperature, humidity, amount of sunshine...That said as far as how much protection I'd guess at around 2 to 8 F. Through a winter only the hardiest plants are going to get enough protection from row covers alone. If you have hoops and row covers in place then it wouldn't be hard to add builders plastic or greenhouse film or something like laceyvail does with hay.

Evidently plants don't get windchill like warm blooded animals but row cover does block wind. It is nice and cozy in the tunnels. The idea is to put greenhouse film on top of the row cover, as I said above, so there is another layer of protection that can be removed when desired.

I use row covers for some things too, but, one of the disadvantages to them is wrestling with them in the wind which is not fun when one is trying to grab some veggies and then get the darn thing weighted back down. All methods of season extension have their pros and cons.

Plants definitely feel wind chill, less with a row cover. The biggest advantage of coldframes/tunnels is keeping your plants out of the wind.

Thanks all. Keep up thinking about extendin the season.

Here is a picture of my Cold Fram in process. Need to install the hinges and the cover.

seysonn
now thats what I call a cold frame, your gonna go very nicely with it..

Thank you japus. I am looking forward , beside thinking forward: LOL
I have used CF in the past. It is very cost effective. In the early spring time it is very handy to germinate a lot of things. That box can get pretty warm inside, in a cold sunny day. I have even germinated peppers and eggplants in CF. They are some of the heat loving seeds.
Once my indoor seedling get a little bigger, CF will be the transfer stations. Hopefully , as of early April I can keep my seedling in it.

Technically plants cannot feel windchill. They can be bothered by wind but that is a different definition.

Technically plants cannot feel windchill. They can be bothered by wind but that is a different definition.
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I don't think so, minnie.
Wind or any air circulation around any BODY can increase heat exchange rate . Say, if a plans and the soil are @ 45F and the blowing wind is 30F, it will remove heat, both from the plant and the soil, faster than if there were no winds.
But when a piece rock has been sitting in 15F for hours, the 15F wind blow is not going to make a difference to that rock.

So the windshield factor comes to play when there is a temperature differential. it could be humans, plants, soil etc.

That is why, most often its is the wind that kills the plants more than temperatures. Winds also remove moisture from the plants. Yet another way to cool the plants.

http://www.ksre.ksu.edu/news/story/wind_chill121709.aspx

http://elivingtoday.com/ArchiveArticleDetail.aspx?ID=2258

Only warm blooded animals get wind chill. Wind can dry out plants though!

Only warm blooded animals get wind chill. Wind can dry out plants though!
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Not true. Winds can remove heat faster , when there is a temperature potential or differential between the air and any given body. .
Let me give you and example.
You have a bucket of warm/hot water(lid is closed). If you put outside say when temperature is 50F.

Take two cases: (1)No wind , it is calm. (2) wind is blowing on the bucket. In case 2 water in the bucket will cool faster than case 1.
Your house will loose more heat when the winds are blowing hard. And the house is not a warm blooded animal.

There are many sources showing that plants cannot feel windchill. I gave two. Obviously you didn't read them.

Wind chill only affects warm-blooded animals -- including people. ItâÂÂs an indexed, scientific measure of how wind speed and air temperature combine to impact animal heat loss, Weber said.

âÂÂWe know, for example, that our heat-loss rate will speed up as the air temperature drops. The faster the wind is blowing, however, the more dramatic that heat loss is going be,â he explained.

Wind chill has no meaning for plants, Weber added. Unlike warm-blooded animals, they donâÂÂt try to maintain a particular body temperature year-round.

I'd have to agree with seysonn that wind chill will affect plants and the soil. It's going to get them colder faster but ultimately will only get as cold as the ambient temperature. That's where the protection of a cold frame comes in.

Though the loss of moisture is also a factor.

I also agree with little minnie that plants don't try to maintain a particular temperature. For an evergreen tree it probably makes very little difference what the wind chill is. For lettuce which is hardy to about 18F its going to get colder faster and be colder longer as well as the surrounding soil will be colder.

Hmmmm
Why then do plants shrivel up in the sunlight during hot spells.
Heck all I know is when it's cold and my plants don't look right I cover them.
When it's hot, shriveled up, curled over, drooping, I water and cover them.
Then I sing and play them a tune and they love it.......

I'd have to agree with seysonn that wind chill will affect plants and the soil. It's going to get them colder faster but ultimately will only get as cold as the ambient temperature. That's where the protection of a cold frame comes in. (gocore)
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Exactly gicore. Once the soil,plant, the stone, ... get as cold as the ambient/air temperature wind chill will have no significance other than removing the moisture(Cold air is low RH).

Back to the subject of THINKING FORWARD.

Here is my Cold Fram as work in process.
Almost there.

Great
Trays for drip runoff will catch untreated water, be good for watering as needed

seysonn, what are you planning to do with the cold frame? Looks like you have a pretty good angle to face south.

The one thing that I found when having high east/west/south sides is that the plants near those sides don't do as well as the ones in the center due to the amount of cold season light. That's why I've gone with shallower sides. The compromise is that I need to grow shorter plants.

japus ... good idea for the drip water.

gicore .. south, slightly tilted to southwest is a good angle. But that frame (3ft by 6 ft) will get pretty warm in no time. It is purpose is not so much the light but the heat. The clear panels work jus as a solar heater. Thou it provides light as well. Obviously the center stays warmer than the sides , next to the walls. I might insulate from inside with 1/2" cellofoam. That will be another 15 bucks.

Sounds good. When you get it situated and some plants in there would love to see some pics.

Lots of great ideas above!

Coleman does recommend a shallower box -- (I think it's 8 inches in the front, 12 inches in the back) With the low winter sun, the plants at the edges in a deep box won't get any sunlight. But you'll see how it goes-- will be interested to hear!

I use cold frames, low tunnels, and hay mulch, depending on the plants. What I have to add to the great discussion above are these ideas:

Use entire bales of hay over carrots and parsnips, -- these can be kicked over and the ground underneath will be nice and soft for winter digging when the snow is deep (a simple layer of hay will be weighted down with snow, and difficult to dig under.)

Row covers using AG 19 (not AG 15 ) work great for a zone 5 mountain winter for me -- lots of temps into teens and single digits, some years to minus temps. Do weigh them down with rocks and logs -- NOT those silly little stakes they sell.

Fedco has lots of seeds that have passed "Roberta's overwinter test" which means out without cover during an entire Maine winter. They've got particular cultivars of lettuces, arugulas, kales, spinach, other greens, savoy cabbage, etc. -- have all survived low teens for me with only one layer AG 19. When it goes to single digits or below zero F, sometimes I put some plastic on temporarily.

Another thing I have noticed is that plants under cover can survive lower temps in December than they can in February. I believe it's the heat in the earth that is still there in December, but gone by Feb. So I try to remember the extra layer on very cold nights the further we get into the winter (that is, unless the whole thing is under snow -- then it's well insulated.)

When you get a thaw, so that your rocks, logs, and fleece are not frozen to the ground, then harvest enough for several days! You might not be allowed under the low tunnels for a while.

I love peeking in through little holes in the fleece, trying to see the green under there, knowing that stuff is in there ready to eat as soon as I can get access to it!

Coleman does recommend a shallower box -- (I think it's 8 inches in the front, 12
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elisa .... mine is about 15" front and 30" the back.Probably I will burry it 2 to 3 inches.

I will have two shelves inside. The back shelf will be about 20"H and one in the middle about 10"H(sort of like wooden steps). Under the shelves will be used to store things like empty pots/trays and also put trays to germinate seeds. I like deeper box better. It has more air volume and the temperatures don't fluctuate as fast. Plus it can accommodate some taller seedlings as well.

I see -- I thought you were planting in the ground under the boxes. Sounds like your shelves bring everything up into the light, and the more air volume/more consistent temps makes a lot of sense. It's almost like a mini green house!