Garden Season Over? Not with a Cold Frame!

Niki Jabbour, The Year Round Vegetable Gardener

Enjoying fresh homegrown vegetables and herbs even in the coldest winter months; now wouldn't that be wonderful!

I know what is probably running through your mind: it would nice, but it's wishful thinking.

That is certainly what I always thought anyway.

Then, I popped into visit Niki Jabbour's blog The Year Round Veggie Gardener. There, gracing the cover of her about-to-be-realeased book, was a picture of Niki in her snow covered garden kneeling beside a row of cold frames filled with fresh vegetables.



I knew that cold frames could extend the gardening season, but I no idea they could extend it this far.

I mean, are you kidding? I would love fresh vegetables even in the coldest winter months!

And not only does a cold frame make a winter harvest possible, it also makes it possible to enjoy homegrown vegetables earlier in the spring.

I wanted to know more about cold frames. I thought that you might feel the same way and so I have asked Niki to do a guest post on the subject.

So, without further adieu, I am going to hand the reigns of this post over to Niki:

Thank you so much Jennifer for inviting me to do a guest post on Three Dogs in a Garden! I'm thrilled to be able to share some of my tips on enjoying your own successful winter harvest.

The late January cold frame is a patchwork of various shades of green as the cold season crops 'hold' in their spots until I'm ready to harvest them. From the vibrant lime foliage of 'Bianca Riccia' endive to the forest green, spoon-shaped leaves of tatsoi, each crop is carefully chosen for its cold tolerance and flavour.

Our favourites for a winter frame include arugula ('Rustic' or 'Sylvetta'), spinach ('Tyee'), mache, claytonia and cold-tolerant lettuces like 'Winter Density' and 'Red Salad Bowl'. These crops were seeded or transplanted into the frame in early to mid-September to ensure that they have enough time to mature before the day length dips below 10 hours in early November and the plant growth slows.

The pretty deeply lobed leaves of 'Sylvetta' arugula are smaller and slower growing than the species type, but they still pack a flavourful punch! When harvesting winter greens for salads, I like to take 'a little of this and a little of that', picking the outer leaves of each plant, so that the center can continue to develop.

Tucked in beside 'Sylvetta', claytonia is another top choice for a cold frame. It's incredibly cold hardy and has a pleasing 'wild' flavour. As the small, heart-shaped leaves mature, each pair will wrap around the stem and a tiny,white edible flower will appear in the center.

Our main cold frames are sturdy in-ground structures that are crafted from 2-inch thick local, untreated hemlock. We have topped them with 8 mil thick double polycarbonate lexan for maximum heat retention and light transmission.

That said, a cold frame can also be very simple like this straw bale frame. I always include at least one straw bale cold frame in our winter garden as they are great for protecting crops like kale, collards and leeks.

Top them with a recycled shower door, old window or a homemade sash like ours. Just make sure it's something sturdy that won't blow away during winter storms-been there, done that! Once spring arrives I spread the leftover straw bales on my pathways to keep them clean and suppress weeds, as a mulch for crops like tomatoes and as a carbon source in my composter.

One of the most important tasks in cold frame culture is to vent your structures on mild days. 

Generally from late November to late February, the frames remain closed except for harvesting. 

But, as soon as the temperature rises above 4 degrees Celsius, I crack open the tops to ensure adequate air circulation and prevent heat build-up. As you can see, I don't rely on fancy props to vent my frames. Logs, sticks, rocks, and sometimes even my broken (but loved) pitchfork are up to the challenge.

We love winter carrots! They are incredibly sweet (thanks to the cold weather turning the starches into sugars), easy to grow and take up little space, allowing me to stuff hundreds in my cold frames.

One of the biggest benefits of the winter harvest is that there is very little work to do!

Because the frames are enclosed and the temperatures below freezing, there are no deers or slugs to battle, no disease problems and no watering/fertilizing/weeding from late November to late February.

Timing the plantings of your winter crops so that they have enough time to mature before the day length shortens to less than 10 hours of daylight is important. In Nova Scotia, I plant our carrot frames during the first week of August. Salad crops are quicker to grow and therefore are not seeded until early to mid-September.

Sometimes when September is warm, it can be tricky to get the seeds of cool and cold season greens like lettuce, spinach and other leafy veggies to germinate. To get around this, I often turn to my indoor grow lights to start my fall and winter vegetables. Once the seedlings are a few weeks old, they're hardened off and transplanted into the cold frames.

We love kale and because it is both cold hardy and heat tolerant, we are able to enjoy it 12 months of the year!

The narrow, blistered foliage of dinosaur Kale is a family favourite and once it's touched with frost, the leaves begin to sweeten. Kale is a tall crop, however, and not easy to fit into our in-ground cold frames. Therefore, I tuck them under straw bale cold frames or mini hoop tunnels where they can bide their time until I am ready to harvest.

A super easy way to extend your season by a few weeks in spring or fall is simply protect your crops from the cold temperatures and frost with a simple cloche.

These baby 'Tom Thumb' lettuces lasted until Christmas when covered with these inexpensive plastic cloches. You can also make your own recycled cloches from milk jugs, pop bottles or upside down clear salad containers.

Just use your imagination!


Photo credits on this post go to: Niki Jabbour and Joseph De Sciose. Thanks also to Storey Publishing.

About Niki Jabbour:


Niki is a garden writer and radio host from Halifax, Nova Scotia. Her book, The Year Round Vegetable Gardener (Storey Publishing) will be available in December 2011. Niki's radio show, the Weekend Gardener airs March through October across the Maritime provinces in Canada on news957.com. Niki's work can also be found in Gardens East, Garden Making and Canadian Gardening magazines. Follow Niki's adventures on facebook or at http://yearroundveggiegardener.blogspot.com

Canadians can pre-order a copy of Niki's book, The Year Round Veggie Gardener by clicking here.


Pre-order on Amazon.com by clicking here.

Jennifer: Many thanks to Niki for doing this guest post. Niki and I would love to know your thoughts on the subject of cold frames. I have invited Niki to respond to any questions that you may have.