Cold frame with the lid shut (Mary Lowther photo)

Cold frame with the lid shut (Mary Lowther photo)

Mary Lowther column: Cold frames are essential for winter gardening

A cold frame is a solid structure that covers crops to keep them warmer than the outside

By Mary Lowther

Just because my attempts to produce something edible in a cold frame during winter over the last 13 years have failed, I’m not beaten. Fresh spinach in December would be nice. Author Binda Colebrooke writes about growing crops right through the winter in her book Winter Gardening, encouraging gardeners to make the most of this climate, and if she can do it, so can I.

A cold frame is a solid structure that covers crops to keep them warmer than the outside, thus extending their growing season. Colebrooke recommends the use of portable cold frames or plastic tunnels that can be removed and moved elsewhere as the need arises. Thus, next spring when my winter vegetables no longer need the frame, I can place it over spring vegetables that would benefit from the extra heat.

For our climate, Colebrooke suggests we sow or transplant the following crops in cold frames in September: cabbage, cilantro, lettuce, mustards, radish, rocket and spinach. In October we can also sow or transplant corn salad, lettuce, mustards and rocket.

My downfall has been slugs and wood bugs that appear from nowhere to inhabit the lovely warm quarters I have stocked with food they thought was just for them, but this year I’m going to show them who’s boss. I learned that slugs and wood bugs are attracted to wood, so I lined the box with Styrofoam insulation. David’s friend assured him that a few inches of sand around the plants deters these critters, so I’ll hunt a couple of bucketfuls down to spread over the soil, raise my seedlings in flats inside and plant them through the sand, into the soil.

My previous cold frame was a massive, coffin-like structure not meant to be moved, so this month David made me a light four by three foot bottomless box out of quarter inch plywood nailed to a wooden frame made of 1 inch by 1 inch thick pieces of wood. The back side is 15 inches high, the front is nine inches and the sides slope down between them. I covered two second hand windows on both sides with plastic sheeting and stapled this onto the window frames to use as lids, then puzzled over how to attach them. The windows had metal edges so we couldn’t use hinges, so I figured bungy cords might fit the bill. I had hooks and the cords, so I just screwed in the hooks to the box and stretched them over the windows to hold them down. When it gets too hot, I’ll just undo the cords and pull the windows right off. When it’s too cold I’ll cover the whole shebang with blankets. I may also store jugs of water inside that absorb heat from the sun during the day and release this heat at night to keep the plants warm.

Please contact with questions and suggestions since I need all the help I can get.


Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Group wants to start a pilot program for regenerative farms in North Cowichan. (File photo)
Group looks to North Cowichan for farmland

Land could also be used for affordable housing

The CVRD will reconsider its policies on fireworks after receiving complaints. (File photo)
Cowichan Valley Regional District considers options for fireworks after receiving complaints

Distict only allows fireworks on Halloween and New Year’s Eve, with a permit

Ben Maartman, left, and Murray McNab are running for regional director for Area H North Oyster-Diamond in a Cowichan Valley Regional District byelection later this month. (Photos submitted)
Preliminary Area H byelection results show Maartman up by seven votes, McNab to ask for recount

Results of the by-election to by finalized by noon on Tuesday, December 1

Freighter anchored off Kin Beach in Chemainus. (Photo by Don Bodger)
Cowichan MP hosting virtual town hall on freighter anchorages issue

Residents can participate through MP’s website or Facebook page Dec. 3

Santa will be in Honeymoon Bay on Dec. 13. (File photo)
Santa to visit Honeymoon Bay on Dec. 13

Families must call ahead due to pandemic

A B.C. Ambulance Service paramedic wearing a face mask to curb the spread of COVID-19 moves a stretcher outside an ambulance at Royal Columbia Hospital, in New Westminster, B.C., on Sunday, November 29, 2020. THE CANADIAN PRESS/Darryl Dyck
B.C. records deadliest weekend of COVID-19 pandemic with 46 deaths; more than 2,300 cases

Provincial health officer Dr. Bonnie Henry provides COVID-19 update

Fossil finds at Mt. Stephen. (Photo: Sarah Fuller/Parks Canada)
Extreme hiking, time travel and science converge in the Burgess Shale

Climb high in the alpine and trace your family tree back millions of years – to our ocean ancestors

Kettle bells sit aligned in an indoor fitness studio. (
1 COVID-19 case at a B.C. fitness studio leads to 104 more infections, 6 school exposures

According to case data released by Fraser Health, one case of the novel coronavirus carries a big impact

Cannabis bought in British Columbia (Ashley Wadhwani/Black Press Media)
Is it time to start thinking about greener ways to package cannabis?

Packaging suppliers are still figuring eco-friendly and affordable packaging options that fit the mandates of Cannabis Regulations

Vehicles drive past a display thanking essential workers in Burnaby, B.C. on Sunday, Nov. 29, 2020. THE CANADIAN PRESS/Marissa Tiel
B.C. changing COVID-19 case reporting as virus spread continues

Manual counting takes more time, leads to errors

Black Press Media and BraveFace have come together to support children facing life-threatening conditions. Net proceeds from these washable, reusable, three-layer masks go to Make-A-Wish Foundation BC & Yukon.
Put on a BraveFace: Mask fundraiser helps make children’s wishes come true

From Black Press Media + BraveFace – adult, youth and kid masks support Make-A-Wish Foundation

Christy Jordan-Fenton is the co-author of the book Fatty Legs, which has been mentioned amid the controversy of an Abbotsford school assignment on residential schools.
Co-author of residential schools book condemns controversial Abbotsford class assignment

Children’s book mentioned amid controversy at W. A. Fraser Middle School

Kootenay East MLA Tom Shypitka takes over as energy and mines critic for the B.C. Liberal opposition. Kelowna-Lake Country MLA Norm Letnick (right) moves from health critic to assistant deputy speaker. (Hansard TV)
B.C. Liberals pick critics to take on Horgan’s NDP majority

Interim leader Shirley Bond takes seniors, long-term care

Left to right: A screenshot of NTC nurse navigator Lesley Cerney, FNHA regional mental health manager Georjeana Paterson and Island Health’s medical health officer Dr. Charmaine Enns addressing Ehattesaht community members from Ehatis reserve in a Facebook live update. (Ehattesaht First Nation/Facebook)
Medical team sent to Ehatis reserve near Zeballos to guide community through COVID outbreak

17 cases, eight recoveries and no hospitalizations as Island Health praises First Nation’s response

Most Read