Cold Frame...Portable Greenhouse for seedlings.
 

I am not growing for market but I thought this question might be answered best here.

I am in Indiana zone 6a. I have always started my tomato, pepper and other garden seeds indoors under lights using a spare bedroom. I had enough stands and lights so I was able to start a couple hundred plants or so and keep them indoors until time to harden them off to plant outdoors.

I am losing most of the spare bedroom to my wife for her use (she is my best friend so its OK) but now I need a new plan. I will have 1 lighted 4 shelf stand with 2' x 4' shelves. That is still plenty of room for seed starting several hundred vegetables and flowers. But when its time to pot up they will need to go outdoors in early spring. I usually start things rolling around March 1 with some earlier and some later. Which means they will need to go outdoors a few weeks later.

I am thinking about a passive heated cold frame or portable greenhouse to be used only for spring seedlings 4-6 weeks a year. I might be building a permanent heated greenhouse but that is 2-3 years away.

Does any one have any suggestions on these things? Buying? Building one?
Brands?, etc.

Any advice is appreciated.

I bought this 5 years ago and have been very pleased. [url]http://shop.readydogkennel.com/Auto-Venting-Dual-Window-Cold-Frame-RGH-4322K.htm[/url]

I line the slides with spray painted black 1/2 gallon milk jugs (filled with water). I also built a polystyrene cover for it that is covered with a tarp (polystyrene foam boards are not UV stable) that I put on at night to retain heat much better. It is on my deck up against the house facing south. Empty it holds 4 flats, but with the 1/2 gallon milk jugs on the sides it holds 3 flats.

I use it to hold my cool season crops before they are planted out. And then once those go into the garden my peppers and tomatoes enter where they live for about 3 weeks until it is plant out time. The auto-vent is essential for me since I'm not home during the day. On windy days the auto-vent can flip around, so I secure it with a piece of twine to one of the milk jug handles so that doesn't happen.

It doesn't sound like this would be big enough for your uses, but they do offer a double sized one. Not sure our situations will line up exactly, but maybe the concept will be helpful.

You did not mention how handy you are or what sort of space you might have for this temporary outdoor set-up. I doubt it would be too portable, but it could be disassembled/reassembled each year.
For 100 plants, you could definitely use about 50 linear feet of preferably south-facing shelving. You could go with wider 18" shelving and double up and get away with 25 feet perhaps. One shelf at 2ft high and another at 4ft high and you are down to about 12 feet of south-facing wall.

3 steps:

1) Put 3 standard pallets (48"x40") on solid level ground, fasten them together side-by-side so you have a 40"x12ft platform and cover with 1/2" plywood.

2) Build a 6-8ft high 2x4 stud frame around it and incorporate (2) 12 foot long x 18" wide shelves on the south wall at 2ft and 4 ft high.

3) Wrap the entire thing with thick poly-film using staples, do the ceiling last to make it more drip proof. Make sure your open seam is on the back of the structure so you can untie it and walk in.

Your structure is built, you have the shelving you need and 12ftx22" of open space to allow watering and care. It will be heavy-duty enough not to tip over, but strong winds could shred the poly.

[QUOTE=jmsieglaff;609056]I bought this 5 years ago and have been very pleased. [URL]http://shop.readydogkennel.com/Auto-Venting-Dual-Window-Cold-Frame-RGH-4322K.htm[/URL]
.[/QUOTE]

Thanks so much for posting your link. Like seymour_man, I'm looking for a way to start my seeds outside this year. Since I want to be able to keep them in there for up to 3 months I found something else on their site that should work great for me, their 4 shelf mini greenhouse: [URL="http://shop.readydogkennel.com/4-Shelf-Mini-Greenhouse-IS-66402.htm"]http://shop.readydogkennel.com/4-Shelf-Mini-Greenhouse-IS-66402.htm [/URL]
I've seen similar ones, but they generally look cheap to me. This looks like it will stand up to some use. Looks like a good company, though their shipping is much more than I usually consider paying.

So thanks for sharing your experience with this company and your suggestion to use plastic jugs.

I make my high tunnels out of chain link top rail, connected with metal conduit fittings. Top rail is about $1 a foot, and you can build anything with it, structure-wise.

[QUOTE=Dak;609343]Thanks so much for posting your link. Like seymour_man, I'm looking for a way to start my seeds outside this year. Since I want to be able to keep them in there for up to 3 months I found something else on their site that should work great for me, their 4 shelf mini greenhouse: [URL="http://shop.readydogkennel.com/4-Shelf-Mini-Greenhouse-IS-66402.htm"]http://shop.readydogkennel.com/4-Shelf-Mini-Greenhouse-IS-66402.htm [/URL]
I've seen similar ones, but they generally look cheap to me. This looks like it will stand up to some use. Looks like a good company, though their shipping is much more than I usually consider paying.

So thanks for sharing your experience with this company and your suggestion to use plastic jugs.[/QUOTE]

Dimensions are way too small for practical use for tomato/pepper plants anyhow... Overall dimensions: 66" H x 40" W x 20" D

10/20 trays need about 16" x 24" of space for breathing room. I have seen a bunch of small (and well designed) green houses that fall short on practical dimensions. Why the hell are they only 20" deep? I don't know why they do not design these for 48wx24d so you can comfortably fit 3-4 trays per shelf and close it up nicely. Come on, give me 4-6 more inches! 4 shelves with 66" of height???? If you are growing out tomato and pepper plants, you can only practically use 2 shelves (1-2' from the ground and another at around 3-4') ... these plants need some vertical space too. This might be great for a few trays of 4-6 week old seedlings, but then what? I think these are more suited for people that grow flowers and not vegetables. :roll:

Go bigger for more plants!! Here's a cheap option with more space [url]http://www.ebay.com/itm/8-Shelves-Greenhouse-Portable-Mini-Walk-In-Outdoor-Green-House-2-Tier-New-/181572894232?hash=item2a46967e18:g:KH0AAOSwLa9UWfcJ[/url]

I start hundreds of seedlings indoors in my living/great room on a 6 shelf metal rack unit that is 4 feet long. I attach my grow lights. When it is time to pot up and move outside, I have a Spring Gardner greenhouse that I put up on my deck. It's 6 by 8 ft., has zip doors on opposite sides as well as velcro windows on the long sides. I break down my shelf metal rack into two 3 shelf metal racks and put each one inside the greenhouse along the 8 ft. side. I can fit another shelf unit along the back. The greenhouse I bought at Blairs Farm and Fleet for under $200 and I had the metal racks and lights. So far, so good. I can put a portable heater inside along with a thermostat. The only thing is I wish I had bought the 8 by 10 ft. unit. They always say, go bigger and that is true. For the last few years, I have been starting at least 800 seedlings for myself and others. When I whittle that down, the 6 x 8ft. unit will be more than enough.

Farmette, do you insulate the bottom or keep the "natural" floor. I used styro in mine and it helped keep the temp a few degrees warmer. Maybe the sun hitting the ground compensates for the cold being radiated form the earth.

- Lisa

@[URL="http://tomatoville.com/member.php?u=15428"]Rajun Gardener[/URL] and @[URL="http://tomatoville.com/member.php?u=19003"]rhines81[/URL]
Thanks to both of your for pointing out the shelf problem. Rajun, I looked at the one you linked and while I really like the price, I'm skeptical about that cover. What do you think of [URL="http://www.minigreenhousekits.com/7-x-5-Portable-Greenhouse-Kit"]this one?[/URL] It doesn't come with shelving, I can improvise that pretty easily, but the venting system looks like a great feature.

I bought a bigger green house with that cover and it lasted 2 seasons but it was in the sun all year, I think you're gonna have the same problem with the one you posted and for that price you can get a bigger one. I'm warning you now, green houses are as addicting as growing tomatoes, once you get one, you'll want a bigger one. You can always replace the plastic as needed about every 4 years is normal even with good green house plastic.

Grow bigger!!!! :)):)):))

[url]http://www.ebay.com/itm/New-Hot-Green-House-12X7X7-Large-Walk-In-Greenhouse-Outdoor-Plant-Gardening-/172210680200?hash=item28188e7188:g:hzEAAOSwcvdXO8vO[/url]

Go bigger! I started just looking at cold frames, LOL. At this point in my life I want this close to the house so space is a factor, I just don't have a lot of space if I factor in convenience and access to electricity, as I plan to use my heating mats. Got to say though, some of those double wall polycarbonate paneled greenhouses look awfully nice.

Well I tried to help you make the plunge. LOL Harbor freight has some poly GH's. Did you see this one? It's small and has room for what you need. [url]http://www.ebay.com/itm/New-7-x3-x6-Tomato-Walking-in-Greenhouse-Outdoor-Plant-Gardening-Green-House-/172474949192?hash=item28284ede48:g:NrcAAOSwQaJXQ~sZ[/url]

I do appreciate your help and certainly can see how size can be a very slippery slope. I did look at Harbor Freight, let me see how well this works this year. At the moment, I see myself only using this until May, it will be too hot to do anything at all in a greenhouse over the summer.

The summer heat is a problem for me too probably more than you. I use the GH from Sep-April to extend the fall season, over wintering plants, growing hydro tomatoes, starting fall seeds and raising Spring seedlings. It was a nice 78 inside there today with outside temps in the 40's. Good Luck with whatever you decide and have fun and a good season.

[QUOTE=Rajun Gardener;609478]Go bigger for more plants!! Here's a cheap option with more space [URL]http://www.ebay.com/itm/8-Shelves-Greenhouse-Portable-Mini-Walk-In-Outdoor-Green-House-2-Tier-New-/181572894232?hash=item2a46967e18:g:KH0AAOSwLa9UWfcJ[/URL][/QUOTE]

This is actually a GREAT deal, this size is selling for double this price elsewhere!

Oops! Sorry, I meant this one which showed up in another search when I clicked on the link: [URL]http://www.ebay.com/itm/Garden-Portable-Wooden-GreenHouse-Cold-Frame-Raised-Plants-Shelves-Protection-/201733397650?tfrom=181572894232&tpos=top&ttype=price&talgo=undefined[/URL]

[QUOTE=Dak;609593]@[URL="http://tomatoville.com/member.php?u=15428"]Rajun Gardener[/URL] and @[URL="http://tomatoville.com/member.php?u=19003"]rhines81[/URL]
Thanks to both of your for pointing out the shelf problem. Rajun, I looked at the one you linked and while I really like the price, I'm skeptical about that cover. What do you think of [URL="http://www.minigreenhousekits.com/7-x-5-Portable-Greenhouse-Kit"]this one?[/URL] It doesn't come with shelving, I can improvise that pretty easily, but the venting system looks like a great feature.[/QUOTE]

I had to really laugh at this "use" that they highlighted ... "[FONT=Arial]Doubles as a portable shed or a get away sun room for relaxation purposes[/FONT]" ... HA!!! Who would go into a 5x7' tent to relax?

Dak, this is OK for some purposes and it is economical, but I would really doubt that it would hold up to a foot of snow or any good wind storms. It might get by in south Texas for a Dec - Feb chill, but not sure it would hold up to a late March noreaster in New England/Mid Atlantic.

[QUOTE=Rajun Gardener;609605]I bought a bigger green house with that cover and it lasted 2 seasons but it was in the sun all year, I think you're gonna have the same problem with the one you posted and for that price you can get a bigger one. I'm warning you now, green houses are as addicting as growing tomatoes, once you get one, you'll want a bigger one. You can always replace the plastic as needed about every 4 years is normal even with good green house plastic.

Grow bigger!!!! :)):)):))

[URL]http://www.ebay.com/itm/New-Hot-Green-House-12X7X7-Large-Walk-In-Greenhouse-Outdoor-Plant-Gardening-/172210680200?hash=item28188e7188:g:hzEAAOSwcvdXO8vO[/URL][/QUOTE]

I have to agree that bigger is better, but the 'cheap' pup-tent type hoop houses just will not hold up to the wind with their coat hanger type frames and light weight. Need wood and HD Plastic or acrylic walls with a heavier frame, or we are talking about a yearly disposable greenhouse which could end up trashed by mother nature even before one season ends.

Dak is in Central Coast Cali, I don't think a snow load is an issue. What do you mean it's not relaxing to get sun, I love the fact that when it's 40 and windy, the GH is toasty. That's usually where I drink my first cup of coffee. You can reinforce them, I even cemented 2x4's and screwed the frame to the post, 3 years and still going. Disclaimer: It hasn't been through a hurricane yet.:?!?::)):))

Edited to add: The frame is 3/4"EMT, all it needs is a few more purlins.
[IMG]http://i1116.photobucket.com/albums/k570/robnms/Mobile%20Uploads/20150209_154549-1.jpg[/IMG]

[QUOTE=Rajun Gardener;609656]Dak is in Central Coast Cali, I don't think a snow load is an issue. What do you mean it's not relaxing to get sun, I love the fact that when it's 40 and windy, the GH is toasty. That's usually where I drink my first cup of coffee. You can reinforce them, I even cemented 2x4's and screwed the frame to the post, 3 years and still going. Disclaimer: It hasn't been through a hurricane yet.:?!?::)):))

Edited to add: The frame is 3/4"EMT, all it needs is a few more purlins.
[IMG]http://i1116.photobucket.com/albums/k570/robnms/Mobile%20Uploads/20150209_154549-1.jpg[/IMG][/QUOTE]

Well, I don't think my body would appreciate the vitamin D from the Sun in a 5x7 Green pup tent. Warm and toasty, maybe, but hardly a relaxing area considering that plants would take up most of that room as well ... walk-in, water, leave .... no relaxing in that small space! :))

Rajun Gardener is right, no snow here. The months that I plan to use it, Feb - May may be cold, but usually not fraught with bad winds. While I am not handy with construction, I do have a husband and son that are that I plan to enlist to set up and bolt her down.

The ebay offerings also, all come from China. When I can, I prefer to support US businesses.

I really do appreciate you all steering me away from a bad purchase, there is a wealth of experience here, thanks for all your comments.

[B]Exaco Trading Juwel Easy Fix Double Cold Frame[/B]

... from Amazon.

Looks a little like jmsieglaff 's set up.

This worked well for me. If hail is forecast I cover the top with styrofoam and tie it down with tent stakes. It is a process. I really like the protection from wind on the babies.


I've put up the soft sided too, but on the deck where it is protected and shaded :(. It needs reinforcing in my climate.


- Lisa

As I mentioned above, I use styrofoam on the ground to keep the cold soil from cooling the trays down.

[QUOTE=greenthumbomaha;609505]Farmette, do you insulate the bottom or keep the "natural" floor. I used styro in mine and it helped keep the temp a few degrees warmer. Maybe the sun hitting the ground compensates for the cold being radiated form the earth.

- Lisa[/QUOTE]

Lisa: I have a wood deck off my patio doors and I set up my portable greenhouse right on the wood.

You have my situation almost exactly (here in Indiana 5b). But I've got perhaps a bit more room. I start my plants in my wife's sewing room where we have a home made plant stand that I built 40+ years ago. I get one shelf; she gets three. ;) But... I move the plants into the attached garage in March. I have a south-facing window + T8 lights on pulleys that I can raise and lower easily. Then about April 15th, the plants go to the cold frame -- a Juwel that I got at Amazon several years ago.
[URL]https://smile.amazon.com/Exaco-Juwel-BioStar-Premium-Frame/dp/B002R5ASVW/ref=sr_1_1?ie=UTF8&qid=1484338570&sr=8-1&keywords=juwel+cold+frames[/URL]

Not cheap, but very well built and should last my lifetime and then some. Normally, I can get by with using several gallon jugs of hot water at night on very cold evenings. I get my first Red Robin cherry tomatoes in May, so this system works well for me. It includes the automatic opener/closer, and that makes things a lot easier to manage.
-GG

Costco online is having a very short lived sale (it ends today) of the cold frame above. It is very sturdy compared to the lower cost model from this company. Cost is $229 plus whatever your state tax is.

Yes, its very short, and I spend a great deal of spring bending over it. It's so handy for protecting seedlings from the wind and squirrels for those that can't have a small greenhouse which someone over the fence might see (rolling eyes). You'd think they would prefer me standing up but(t)...

- Lisa