Depending on where you live, starting a garden in early spring can be a challenge. Where we are, in Montreal, Quebec, early spring usually finds the ground covered with snow. However, you can start your garden with some planning even though temperatures may still be very cold.
The principle here is similar to what we explain on the blog "How to Extend Your Harvest Season." With the help of some tools, you can warm the soil temperatures to sow some hardy vegetables and flowers.
The first thing you want to do is to pre-warm your soil. The proper soil moisture will help to trap the daytime heat. The Gardening Know How's website advises that "it's important to have the right kind of soil and moisture levels. Even soil with plenty of organic matter and good drainage will hold onto just enough water to keep the soil warmer than dirt that is bone dry. Having water in the soil—but not enough to saturate it—will allow it to absorb and hold onto daytime heat better." In most Northern climates, you will also need some tools to help speed up the processes - more on this below.
When planning your spring sowing, keep in mind that these techniques are great for hardy vegetables. Warm-loving plants, such as tomatoes, will not grow as the temperature is still low for them.
Be sure to give it at least a week to warm the soil before sowing. If the soil is too cold, seeds will not sprout.
Here are some options you can use for an early gardening season:
Cold Frames are a great option to warm up the soil. In her website, The Savvy Gardening, writer Niki Jabbour, explains that "a cold frame is just a box with a clear top. It's unheated but captures solar energy and shelters crops from the elements – cold temperatures, wind, ice, and snow. You don't need a large garden to accommodate a cold frame." You can grow hardy vegetables such as lettuce, radishes and arugula. Check the height of your frame to be sure the plants have enough space to grow.
An important point for the successful use of cold frames is ventilation. If temperatures reach 4ºC, you want to open it to allow air circulation. Not allowing proper ventilation will result in a too hot zone that will be affecting the plants' growth. Another important point is to allow light to enter. Be sure to clean snow or leaves that have fallen on the cover.
Low tunnels are another option. Cover the row with transparent plastic or garden frost blanket. Low tunnels are temporary structures, and this allows you, as temperature rises, to remove the cover. If you want to warm the soil faster, you can lay a thin plastic mulch for one or two weeks after the snow melted and the soil dried a bit. Remember to sow hardy vegetables.
Note on plastic mulch: most farmers use plastic mulch, and you can find it at garden centers. But you can buy plastic used in construction or for wrapping at a hardware store.
Create garden cloche with transparent milk containers or water jugs. They may not be as attractive as a nice glass cloche, but they're affordable. Depending on the temperature and humidity level, you may or may not need to leave the cap. Be sure you check them every couple of days to avoid problems.
Even when using these techniques, soil temperature should be between 4º-5º C to plant. If you don't have a soil thermometer, take a look at the soil, and if it is no longer overly wet or frozen, it's most likely ready to plant.
What To Plant In Your Low Tunnel Or Cold Frame?
Here is a list of some hardy vegetables you can start before your last frost day:
- Asian greens (Pak Choi, Tatsoi, Mizuna)
- Beets
- Broccoli
- Brussels sprouts
- Cabbage
- Chard
- Kale
- Kohlrabi
- Lettuce/mesclun
- Mache
- Onions
- Scallions
- Spinach
One last word on starting your garden early in spring.
These strategies will work for direct seeding and transplanting seedlings. If you choose this last option, be sure you harden off your plants. You can explore this blog to grow a healthy garden.
When temperatures drop at night to freezing levels, you may want to give extra protection to the plants. You can cover them with an old blanket, with a clean carton container (also great for strong winds), or big plastic containers (a large ice cream container will work great!).
Have fun because gardening is all about experimenting and having fun.
