This particular cold frame is not elaborate, but it works quite well. Made of plywood and poly sheeting, its sloped shape allows for rain drainage while keeping the plants within warm in the cooler months of the year.
how to build a temporary cold frame
This arched hoop house-style cold frame is not elaborate, but it does the trick! Made to fit just inside the walls of a raised bed, the two plywood ends keep wind out of the tunnel, and the plastic sheeting overtop allows plenty of light to reach your plants.
Do you find that plastic water bottles build up in your house or recycling bin? Well, save some, and you too can create this unusual, but effective cold frame! If you add a little silicone caulk between the bottles, you can make it completely enclosed, or you can leave the gaps to allow some vent space. Whichever you do, this reuse project makes the most of what would otherwise be landfill fodder or recycling plant materials.
Another idea using salvaged windows, this cold frame is built much taller, enabling it to be used for larger plants. The windows fold open from the center to the outsides, making it surprisingly easy to vent on a warmer day.
This vertical cold frame is constructed almost completely of repurposed window frames, making it a great upcycling project as well! Built to rest against a wall, it is half-greenhouse, half-cold frame, and all very useful.
This upcycled pallet and window cold frame might be free, if you have a source of used pallets and windows! With a little ingenuity, you can have a very workable cold frame that will offer lots of protection to your plants for very little cash outlay.
This cold frame is a permanent structure, as the bricks are in fact mortared together. However, the lid can always be lifted if the weather gets too warm. If you live in an area that has a short growing season, this might be perfect for you!
At their simplest, cold frames are bottomless boxes that are set over plants in the garden to protect them from cold weather. They are usually built low to the ground and have a transparent roof to let in light.
Cold frames can be bought or constructed from timber and plastic, but concrete blocks or bricks can also be used. You can even construct a simple, bottomless wooden box and set it in the garden or atop other good soil in a sunny location. Watch our video, below, for step-by-step building instructions!
For really easy covers, I use the plastic boxes from lettuce. I then anchor them with a rock. Very easy if you have no building skills. You can keep them on easily. If it's really cold, you can cover all of them with a large sheet of plastic. I save the boxes all winter. Another trick I did last year, was use half an eggshell filled with seed mix. I planted the tomato seeds in this, put them directly in the ground and covered them with a box. Had great tomatoes, even though I planted in late May. Protected them from a late frost and I didn't have to transplant. So no shock to the plants. Like little mini greenhouses. Put the drip line to each one.
Cold frames are a great season extension tool to help you garden in cold weather or to start warm weather seedlings long before your last frost date. Learn all about cold frames (including DIY cold frames) in this article!
Artificial lighting (grow lights) is an ideal choice if you have the indoor space. If your indoor space is at a premium but you want to start garden seedlings to get a jump start on the growing season, cold frames are your best bet.
This means your plants get natural sunlight and extra warmth. In most regions, a cold frame can be used effectively to grow winter seedlings and crops, though if you live in a climate zone below USDA Zone 6, you may need a more fortified version than the one I use in my garden.
Since the plants inside will only be a little bit warmer than the outside air, cold frames are mostly used for frost-tolerant crops during the winter. Check out our article Easiest plants to grow in the fall and winter, for a complete list of frost-hardy plants.
I built a nice, solid cold frame of wood, with a plastic foil covered lid and automatic openers. I measured the temps day and night and was disappointed to find that it barely stayed warmer inside than out during nights. Like 1.5 Celcius. Would glass or plexiglass be that much warmer than plastic foil? It is built pretty tightly, and the wood is fairly heavy.
1. The best placement for a cold frame is one that gets south-facing, early morning sunlight. Ideally, you could position it next to another larger structure that traps heat, such as the side of a house, large rocks, etc.
Temperature differentials between inside your cold frame and outside your cold frame are going to vary based on your weather:-Scenario 1: Consecutive sunless cold days and cold nights are going to eventually sap pretty much all the heat out of your high tunnel. In this scenario you may only be able to maintain temps 1-5F above outdoor temps.-Scenario 2: On cold below-freezing sunny days, you should expect cold frame temps 5-10F above outdoor temps.-Scenario 3: On warm sunny days, your cold frame can get quite warm, 15-20F+ above outdoor temps, which would likely require you to open the structure (your automatic openers probably do that for you).
Technically, yes, but that would be difficult to do because: a) cold frames are typically relatively small, and b) to continue producing heat, hot compost has to be kept in a large pile and turned periodically, both of which would be difficult inside of a cold frame.
The easiest ways to keep a cold frame warmer are: 1) to put them in the ideal location relative to the position of the sun, 2) build or buy a quality cold frame that has adequate thermal mass and minimal draft so as to retain as much heat as possible, and 3) use supplemental heat sources such as soil warming cables.
The purpose of DIY cold frames is to extend the summer growing season into the cooler months. You can buy ready made cold frames or kits which are self assembled, but it is easy to create a makeshift one out of common household objects like plastic bottles. Or even to create something more permanent from unwanted reclaimed materials such as bricks or doors.
These easy-to-erect DIY cold frames will mean you'll quickly be able to start your seedlings and plug plants and harden them off before they're planted out in your garden in spring. Not only will this improve performance, it speeds up their establishment in the garden too.
In the colder months of the year, you can use your DIY greenhouse designs and cold frames to overwinter seedlings and get a head start on next spring. You can even use them to sow trays of vegetable seeds like cabbages, lettuce, and peas for super early harvests the following year.
Just like our favorite greenhouse ideas, these DIY cold frames are a brilliant way of improving your vegetable growing as well as providing a perfect environment for hardening off plants. They're budget friendly and easy to make too.
'My cold frame was very easy to construct and cost me nothing to make,' says Aoife, who showcased her DIY cold frame on @green_aoife on Instagram (opens in new tab). 'I used bricks that we'd taken out from an internal wall during a bit of house renovating and an old, broken, hinged shower door. I stacked the bricks against one of our garden walls to make a rough rectangular frame and then put the shower door on top as a roof.
'The hinge action on the shower door allowed me to open and close the cold frame with very little effort. I used the cold frame to help harden off my seedlings ready for planting out in the mini veg garden. I had a really small garden space at the time and tried to pack a lot into that tiny area.
Jess @theallotmentgeek (opens in new tab) first started her allotment journey, aiming to reuse as much as possible to keep her carbon footprint down. 'When we had a wardrobe going unused at home, we found the perfect opportunity to create a new cold frame for our young plants.
'When it was in place we then painted the wardrobe with a clear exterior wood paint to prevent any water getting into the wood and rotting it, and it was good to go! With 20 ($27) and some creative thinking, you can easily create DIY cold frames.'
So here's a cheap garden idea where plastic soda bottles have been used to create a clear screen to act as a lid for your cold frame. A simple timber construction, or even an existing wooden box can be used as the base. Then create a frame to fit the top of your base using strips of wood cut to size and nailed together.
Make a hole at the base of your plastic bottles and feed a narrow strip of wood (bamboo canes cut to size are ideal) from top to base forming a column. Line these up next to each other and fix into your frames before attaching to the base of your DIY cold frame. It's an easy, eco friendly option for a sustainable garden.
Niki Jabbour of Savvy Gardening (opens in new tab) created this cold frame from a kit made from cedar wood and polycarbonate. 'I got it from a local building supply company and I just had to assemble the pieces.
'I use cold frames to extend the harvest in spring and fall as well as to harvest all winter long. I live in a hardiness zone 5B and we have long winters with a lot of snow. Cold frames allow me to enjoy a harvest of cold season crops throughout the greenhouse growing calendar like spinach, winter lettuces, Asian greens, scallions, kale, carrots, and other hardy vegetables throughout winter.'
Louise (@louiseashton_in_france on Instagram (opens in new tab)) made her DIY cold frame out of an old window from her house which needed replacing. Windows make ideal materials for DIY cold frames as the transparent glass is ideal for letting vital light to your seedlings.
And to add a fun finishing touch to an already lovely looking cold frame, Louise took things one step further with a splash of outdoor paint. 'I painted it with a pop of pink to match my tomato cages,' says Louise. 'The color is bright it always puts a smile on my face and will do even more so when filled with young seedlings.' 2ff7e9595c