For over ten years I have grown my own garden transplants by carrying the seed trays out into the sun on warm days and bringing them in every evening. In the last 3 years, I was juggling over 20 trays in and out of the house. This method uses natural light to produce strong, non-leggy transplants — but if you’re growing lots of seedlings it is excessively laborious!
It had to stop! However, my husband and I do not have impressive construction skills. When a friend from Pecandale Farmstead gave us some old windows, she also gave us an idea. Straw bales + old windows = instant cold frame.
Photo Caption: Our straw bales varied in length, but most were about 37" long.
The only materials you need are straw bales and some sort of windows. Craiglist or Freecycle are great options for recycled windows. If you happen to get plexiglass or acrylic ones, they are much less likely to shatter.
The only tools needed are hands (but gloves are recommended).
Photo Caption: Although the cold frame itself was constructed in minutes, it took us a bit longer to clean out a site for it.
Choose a site that isn’t very shaded, although it is okay for it to get part sun in the south. The more sun your site gets, the more vigilant you will need to be about ventilating your cold frame on warm, sunny days. On sunny days ranging 35°F to 40°F, open it a crack. Once daytime temps reach 50°F you may need to open it entirely. Cloudy days don’t require as much ventilation.
Unheated cold frames allow you to overwinter plants that are from a zone (or two) warmer than yours. So, someone in zone 6 could overwinter plants that usually live in zone 7 or 8. In zone 8, you’d be growing plants from zones 9 & 10. It’s also a great way to get your seedlings started and ready to plant out by your frost-free date.
Photo Caption: Much better! It's a good idea to put down wet newspapers and mulch or some other weed barrier under your cold frame.
If you’re placing your cold frame on bare soil, weeds will be just as happy about the cozy environment as your transplants and pots. The easiest way to keep from weeding in the wintertime is to put down a barrier to block the germination of weed seeds and wandering roots. A layer of mulch will insulate plants from the cold ground but beware of pests like slugs hiding there.
Photo Caption: It took a little bit of maneuvering to get the straw bale placed to support the windows. We "eyeballed" it -- no measuring required!
You can stack your bales in several ways to make your frame tall or short. Ideally, the plants underneath shouldn’t be so deeply set they can’t reach the sun. If you only plan to do seed trays, make the frames lower or put the trays on top of something to elevate them closer to the light. If you are overwintering taller container plants, make the frames higher.
If there are gaps between the bales, stick extra hay in the cracks to reduce drafts.
Photo Caption: The finished product will hold more trays than I can utilize in my garden. We'll also use it to harden off some of our taller potted plants.
Minutes later and you’re done! Nothing else is necessary to make your cold frame ready for transplants and pots.
If you have very cold weather consider adding extra heating elements such as black water containers (they absorb sun during the day and release it slowly at night) or bubble wrap on the glass for additional insulation.
Photo Caption: Here's how it looks with plants inside. The windows can be slid to the side for ventilation on warm days.
Ventilation is simple: just place a brick under one end of a window to prop it up, slide it partially to the side, or remove it entirely. Be sure the window is secure to avoid crushed transplants or broken glass.
All done!
I can’t tell you how excited I am not to do the seed tray parade every morning and evening for 3 months.
Brilliant Eliza! I have seeds I need to get planted! I don’t think I have as many as you….but they do need to get planted just the same!
Janet, The Queen of Seaford´s last [type] ..Great Nights and Lovely Mornings
Twitter: appalachianfeet
Good luck with them (may the anti-dampening off force be with you).
Husband?! I thought he was a boyfriend five or six posts ago. Did you get hitched and not tell us? Or did you just have a spare husband lying around somewhere?
Anna´s last [type] ..mark: Keeping new born chicks warm
Twitter: appalachianfeet
Haha… yeah I think we were at the fiance stage last time we talked. We skipped straight to married (Oct 8th) and my photos are on another computer so I haven’t done a post about it yet.
Twitter: flaneurgardener
*sigh*
I’m so jealous! Though considering that I go to my garden every weekend or other, I really have to lay off with the cold-frame plans! (I do, though, currently live alone in an apartment that’s large enough to leave one room unheated, so there will be a suitable temperature for my seedlings, I hope. Then I guess they’ll have to handle the hardening off themselves, perhaps with the help of some plastic coverings.
Flâneur Gardener´s last [type] ..Pruning Poetry
Twitter: appalachianfeet
I understand! I think we all want the “next size up.” Every time someone posts about their greenhouse, my yard always seems too small! Someday…
Sustainahillbilly´s last [type] ..How to Admit When Your Garden Looks Ugly (and Feel Proud)
This is a wonderful idea. I saw it done at farms around here, too. It is a quick method for toasty warm plants.
Donna´s last [type] ..Trees Dressed in Ice
Twitter: appalachianfeet
Yeah, we figured it was even warmer than wood frames!
Twitter: marksvegplot
In a year or two, when the straw bales need replacing, you can compost your cold-frame too!
Mark Willis´s last [type] ..SBDS
Twitter: appalachianfeet
Yep! It’s so hard to resist planting mushrooms in them right away!
Twitter: plantpostings
Wow, great idea! I think I could do that! I see that the Forsythias are blooming by you–nice!
PlantPostings´s last [type] ..Garden lessons learned: winter 2011-12
Twitter: appalachianfeet
You definitely could! We always enjoy the forsythias on the property next door.
This is awesome!! I may do this next winter. I just started seeds inside. Now I have a cool project for the summer – find windows!
Casa Mariposa´s last [type] ..Seed Starting for Zombies
Twitter: appalachianfeet
Good luck on your window search! I hope you find some freebies.
What a great idea. I think the hardening off isn’t quite such an ordeal here. We would sow the seeds in early March and bring them on in the greenhouse. If the temp rose too high we would open the windows and doors. We would just start the hardening off process about 10 days before planting into the borders in late May which was a nuisance, but not for such a very long period. October the 8th, well well, that was our day way back in 1966.
Alistair´s last [type] ..Paeony My Pal Rudy
Twitter: appalachianfeet
I agree, I think a greenhouse makes hardening off much easier! We are planning to build a passive solar house around some citrus we’re planting, but we don’t have room for a fully heated greenhouse right now.
Congratulations on your anniversary, an excellent day for one indeed (also happens to be my husband’s brother’s birthday).
Sustainahillbilly´s last [type] ..How to Admit When Your Garden Looks Ugly (and Feel Proud)
[...] Eliza has written a much more detailed post and included pictures. So check it out. We’re totally thrilled to have the thing up and working. Saves space in the house, keeps our seedlings alive, and all around is just a fun bit of gardening project. Like this:LikeBe the first to like this post. [...]