Start a Spring Cold Hardy Garden in Zone 3
With the uncharacteristically warm winter, and a warming trend on its way, despite the recent snow it may be time to plant cold hardy crops here in Zone 3. On the last segment of the Urban Garden Series I started the process of planting my summer loving crops like tomatoes and peppers indoors. Today I am going to talk about how I plan to grow my cold hardy crops under cover and some of the experiments I am going to do that should help me extend my season and increase my harvests by adapting these methods to my garden.
As many of you saw on my first vlog I set up my hoop house and cold frame in the area of my garden that gets the most sun in the late fall and early spring. I also enjoyed a lunch of leafy greens that I had grown inside. I grew the same ones inside as I am going to plant today and boy was I impressed. The flavor of these greens is so fantastic a dressing would almost hide all of the wonderful flavours.
I am pretty excited to grow these out in the garden. I have experimented with unheated season extension in the past but this year I have put a little more time and effort into it and hope to learn how to apply these techniques in Zone 3 here in Canada.
The first and most important thing to think of is how much direct sun you are getting. My house shades my entire garden while the sun is at its lowest point in the sky between late October and Mid February. Once the sun comes back I get between 4-6 hours of direct sun increasing as the season goes on peaking out at just over 15 hours of direct sunlight on the summer solstice.
I have tracked the temperatures over the course of the last week. The intent of doing this was to see how much protection the two layers were offering. Currently the lowest temperature inside the cold frame was -5c or 23f while outside hit -15c or 5F.
This indicates to me under the two layers of protection I should be able to plant the most cold hardy crops. I am measuring the air temperature and what I would expect is the soil temperature is able to stay above freezing. This milestone should allow me to successfully plant.
Additionally Elliot Coleman in his book Four-Season Harvest is able to plant crops like spinach between January 15th and March 1st. I am confident although we are three weeks after the last date here in Zone 3 it is just about the right time to plant.
I am going to start with cold hardy leafy greens such as Spinach, Mache, Claytonia, Sorrel and Mizuna. All of these varieties are said to grow best in the spring and fall when the soil is cool.
I can expect with really early planting that the germination rate might not be the best so I plan to plant 1/16th of the area inside per crop and come back in 3-4 weeks to plant another and again 3-4 weeks after that. This will allow me to learn how to apply these methods here in Zone 3 while reducing the risk of failure to a few seeds but if I am successful I could be harvesting weeks ahead of schedule and 3 consecutive crops providing me harvests likely until other more warm loving crops are ready.
Spring in Alberta can be unpredictable I may encounter a set back if the seeds I am planting today germinate and temperatures drop off. If temperatures are expected to drop below -5c or 23f I will add a blanket in addition to the two layers of protection to help them through the coldest of the nights.
Planting leafy greens is fairly simple. I simply take a pinch of each of the varieties and spread them over their square. I then will take a little bit of potting soil just to cover them in a thin layer and water them in.
As they emerge I will thin them out eating the smaller ones in my salads while allowing others to grow to full maturity.
I will also be planting a duplicate grid outside of the cold frame but inside the hoop house. I am interested to see if shortly after the first day of spring I can plant these cold hardy crops under one layer of protection and get them to germinate. If so I can cover larger areas in my garden with hoop houses as I have material left over from the original build.
These leafy greens are not the only cold hard crops out there. I will be conducting two other experiments related to cold hardy crops under protection.
Onions and carrots are well known to withstand some pretty low temperatures. In a few weeks when the inside temperatures no longer fall under the freezing mark I am going to plant some peas and carrots inside my hoop house. although again we can expect a lower germination rate if they are successful I can add this method to the strategies I use to grow more crops in the same area and spread my harvest out over the season.
The Third and final experiment I am going to try involves other cold hardy crops like Kale and collards. I am going to try to direct sow some under two layers of protection and then a duplicate indoors to see how the methods vary throughout the growing season. This experiment will also likely need to wait for 2-3 weeks.
Once the seedlings are up I am going to have to be careful that the plants don’t get too cold and too hot.
I will keep the cold frame and hoop house closed even on sunny days until I see the first seedlings emerge. Once I do that I will vent them during the day to prevent them from cooking in the sun and then close it all up again during the evening.
I will also lean towards colder temperatures. On cloudy day after the seeds germinate I will vent the protective layers. Here in Alberta the weather can change quickly and be very different even a few kilometers apart. I would hate for the day to start cloudy and not vent the hoop house only to have the sun come out later in the day and cook them.
Once the seedlings are up I will need to water however far less frequently than in the summer. The overall lower temperatures are somewhat balanced by the increased intensity of heat caused by the protective layers. I will be a little more selective and only water on sunny days in the morning so any water on the plants may have the opportunity to evaporate prior to the cold night time temperatures. If the water sits on the plants over night it can cause damage or even kill the plant.
I am excited to experiment with early season growing outside. If I can do it here in Zone 3 with no supplemental heat that not only helps local gardeners but think of what the vast majority of you can do whom live further south than I do here in Edmonton, Alberta, Canada.
These experiments will help me achieve some of my goals of producing more food for longer into the season and possibly if I am lucky set me up to have a self-sowing annual cold hardy bed. If I let some of these crops go to seed I may be able to let the bed do its own thing and not need to spend any more money while continuing to harvest for years to come.
My First Vlog! Check out the Gardening Biologist Next Door:
Urban Gardening Series Playlist
How to Use a Cold Frame