Growing Vegetables in Northern Climates

I traveled out to Pinehouse (Latitude 55'30°) today and had an opportunity to see this year's community/clinic gardening project.  They were lucky in keeping some early-planted tomatoes alive, but it has been a mild week.  This made me think about the whole notion of planting times in the north.  I usually add a few weeks onto recommended planting times on seed packets, and adjust for our short season.  We are in zone 1, which leaves only the Arctic/Antarctica for a worse growing location. 

So what are the guidelines anyhow? 

Vegetable plots at Pinehouse clinic

The frost dates for Prince Albert (2+ hours south of here) are June 2 (last spring frost) to Sept 4 (first fall frost), so our season would be shorter than that.  I'd estimate about 85-90 days, (though frost is still a potential occurence at any month, so there are no guarantees).  This is important for plants that need longer seasons, like pumpkins (120 days).  You would have to start long-season plants indoors to ensure that they would produce fruit by the fall frost date.  The crop insurance maps can provide information on frost dates, but unfortunately they stop just north of Prince Albert.  I suppose that is reasonable, given that no one grows commercial crops up here in the northern forest!  Internet searches find all sorts of irrelevant information from growers that think they live in cold climates, but don't really understand the north (i.e. they may recommend planting carrots in February, but I can't find my garden under the 5 feet of snow drifts in February). 

So, in the absence of expert data on these things, the recommendations of locals is useful information.  This is a summary of what I have figured out.  Keep in mind that this only applies to plants in the ground or raised beds.  This does NOT apply to plants in pots, as those will never survive over the winter here. 

HERBS:

Winter-hardy:

• Chives - Hardiest herb.  Perennial and spreads itself easily by seeds.  Grow some close to your house so you can easily snip some for your baked potatoes.
• French tarragon - Winter-hardy here. 
• Lovage - Large herb that is winter hardy here.  Tastes like celery greens.
• Parsley - Occasionally lives through the winter.  Start indoors in a pot or sow outside in late May.
• Thyme (English thyme; the edible kind, not the groundcover varieties) - Sometimes lives through the winter, though after a year will get too woody.  It is best to have new plants each year.  Start early indoors or sow outside in late May.
• Mint - There is a wild mint that grows around here.  Many mints would be hardy perennials, though they are also invasive, so I'd recommend NOT planting them in your garden.  Keep some in a pot and never let it go!  

Not hardy, treat as an annual:

• Cilantro - Not hardy in winter.  Sow early indoors or sow outside in early June.   Fantastic in salads and East Indian food. 
• Basil - A tender herb that cannot tolerate cold nights.  Start early indoors and let it go outside after June 5.  It grows fast though, so you could also sow more seed outdoors after June 5.
• Sage - probably not perennial here.  Start early indoors. 
• Dill - plant seed in May, very easy to grow and will easily seed itself if allowed to.
• Rosemary - A slow growing herb that is perennial only in warmer climates (think southern California).  It is far too time-consuming to grow this herb from seed.  Just buy a plant.  You can take it indoors as a houseplant in fall.

Rosemary brought indoors in fall.

VEGETABLES:

Winter-hardy:

• Asparagus - One of the cold-hardiest plants that exists.  I don't grow it, but if I had years to establish a patch, I might try it.  This plant is perennial.
• Spring/Green onions -- plant seed the preceding summer for nicely grown green onions the following June.  You can also sew in early May for green onions in the summer.    
• Larger bulb onions - Start seeds early (April) and transplant in mid May or start as onion sets outdoors in May.   
• Garlic - I am still practicing at growing garlic, but it seems to do okay here.  Plant as garlic cloves in fall.
• Rhubarb - Reliably hardy. Give lots of compost and divide in early spring, if needed.

Seeds suitable for early planting (e.g. first weeks of May)

• Beets 
• Radishes - these really only work if planted early, as they like cool weather
• Lettuce - plant early and replant throughout the summer for a continuous supply
• Spinach - does well in cool weather, so plant an early spring and a fall crop
• Swiss chard - I've seen some pretty spectacular Swiss chard up here
• Onion seed
• Peas
• Carrots
• Potatoes 
• Kohlrabi
• Turnips
• Peas

Probably hardy, but I start early indoors in May:

• Broccoli
• Cauliflower 
• Brussels Sprouts - I haven't tried these, but they should do well here
  

Tender vegetables - Start indoors for longer season plants, sow others in June:

• Tomatoes - Must be started from seed indoors in April or early May to produce any fruit before the first frost date.  If buying as potted plants, don't plant out until after June 4.  Season lengths are 60-75 days.  Pick varieties bred for the shorter season lengths. 
• Peppers - Must be started indoors in April or early May to produce any fruit before the first frost date.  If buying as potted plants, don't plant out until after June 4.



A zucchini variety sold for growing in containers.

• Squash, pumpkins , zucchini - Must be started indoors in April or early May to produce any fruit before the first frost date.  If buying as potted plants, don't plant out until after June 4.
• Cucumbers -  Would be best to give a head-start by starting indoors in April/May or buying as potted plant.  Don't plant out until after June 4.
• Beans - These won't sprout until the soil temperatures reach a certain threshold.  Plant in early June as seeds.
• Corn - My garden is too small, but this can grow here.
• Melons - I haven't tried these, but I don't think our northern summers are very well-suited to most melons, which like long hot summers.

OTHER COMMON GARDEN EDIBLES:

• Strawberries -- hardy, essentially biennial, and benefit from a protective layer of straw in the winter.  Bear fruit best in second year.  Root the runners to keep a continuous supply of second-year plants.  I have a day-neutral variety ("Hecker") which bears fruit over much of the summer.
• Raspberries -- hardy, biennial, bear fruit on second year canes.