Guest Post by Niki Jabbour
In my zone 5b region, a vegetable garden has always typically been a May
to September affair with crops sown in late May, harvested all summer long and any leftovers pulled and eaten by early autumn. Today, our garden has broken free of that traditional schedule and our 2000 square foot veggie plot is a year round food factory supplying us with a bounty of homegrown vegetables and herbs that change as the seasons shift.
Over the years with much experimentation (and epic failures!), I’ve discovered
that the key to a successful year round plot is to grow the right crops at the right time and pair them with the appropriate season extending devices like cold frames, mini hoop tunnels or row covers. Most people who peek into our mid-winter cold frames can’t believe their eyes when they see the bright green clumps of salad greens just waiting to be picked. I’m
often asked how the plants could possibly still be alive in such cold weather. Yet, temperature isn’t the defining factor of success in a winter garden. Rather it’s all about day length and proper crop selection. Once the day length shrinks to less than 10 hours a day in late autumn, most plants stop actively growing. Therefore, when planning a winter harvest, you need to time your crops so that they will be about 90% grown when the day length falls below that magical 10-hour limit. At this point, they
spend the winter ‘holding’ in their protective structures until you’re ready to harvest.
In a backyard garden, I use four main season extenders to protect our fall and
winter vegetables – row covers, cloches, cold frames and mini hoop tunnels. If space
and budget allows, an unheated greenhouse or polytunnel can also be put into winter
production. A row cover is the most basic form of protection and is simply an insulating
blanket. There are different grades of row covers, with light and medium-weight blankets
used to protect crops from a light frost. Heavyweight row covers are ideal for more
serious cold weather protection.
The next line of defense is the cloche. Traditionally, cloches were bell-shaped,
open bottomed glass jars that were placed over crops to create a mini microclimate
and protect crops from cold weather. Today, glass cloches can still be found in garden
centers, but I tend to use plastic cloches or those made from recycled materials such as
old milk jugs or pop bottles. I have had several glass cloches break (they seem to do that
when I step on them!) and picking glass from a garden bed is no fun.
A cold frame is an incredibly versatile structure for a year-round vegetable
garden. Ours are crafted from untreated hemlock boards and topped with a twinwall
polycarbonate sash, which offers excellent light transmission as well as heat retention.
One frame is always reserved for a bumper crops of winter carrots, while the other two
frames shelter an assortment of cold season salad greens (endive, tatsoi, spinach, arugula,
mâche, claytonia, winter lettuce, mizuna, mustard and baby kale), scallions, beets and
herbs (parsley, chervil and thyme).
Easily erected in late fall, a mini hoop tunnel is another valuable tool for a winter
gardener. They are used to cover vegetables in existing garden beds, as well as tall crops
that don’t fit into the low profile of our cold frames – kale, leeks and collards, for
example. Our mini hoop tunnels are made from ½ inch diameter PVC pipes that are bent
in a U-shape overtop our beds. They are then covered with a sheet of greenhouse plastic to capture solar energy.
Top Crops:
When deciding what to grow for a winter harvest, stick to the cool and cold tolerant
vegetables. Don’t be afraid to experiment with unfamiliar crops like mâche, mizuna and
claytonia, however, as you might just find some new favourites! My top crops include:
Spinach – Direct sown in our cold frames in late summer, we enjoy a bumper crop
of tender leaves all winter long.
Arugula – One of our favourite greens, peppery arugula is also extremely cold
tolerant and can be enjoyed until December if covered with a row cover or all
winter long when grown in a cold frame.
Carrots – Carrots have the lovely ability to get sweeter as the temperature
plunges! We grow hundreds of super sweet carrots each winter in our cold frames,
as well as under a thick layer of mulch in the garden.
Kale – Packing a nutritional punch, kale is a winter superstar! It’s extremely cold
tolerant and gives us daily harvests from late autumn into late winter with only a
mini hoop tunnel to shelter it.
Leeks – An essential ingredient in winter soups, our leeks are tucked in for winter
with a blanket of straw and then protected by a mini hoop tunnel.
Parsnips – In late autumn, our parsnip bed is topped with a foot deep layer of
shredded leaves or straw. We begin to dig the roots in mid-winter, once the cold
weather has had ample time to sweeten them.
Mizuna – An extremely hardy Asian green, mizuna adds a lovely ‘wasabi-like’
tang to mixed salads. We grow it in our cold frames as well as under mini hoop
tunnels.
Claytonia – One of the hardiest of the winter salad greens, claytonia has succulent
leaves and tiny edible white flowers. Direct sow in a cold frame in late summer.
Mâche – Perhaps my favourite winter crop, mache is bone-hardy and ready to
harvest from early autumn to late spring. We pick the small rosettes whole and
drizzle them with olive oil and lemon juice for delicious cold season salads.
Niki Jabbour is the author of the award winning book, The Year Round Vegetable
Gardener. Her articles appear in magazines across North America. She is also the host of
The Weekend Gardener, which airs every Sunday from 11 to 1 pm Atlantic time on News
95.7 FM (www.news97.com). You can also find her at
www.nikijabbour.com.
