There is an unwritten (it is probably written somewhere) rule that Calgarians should do most of their heavy outside planting around the May long weekend. Generally, we're past most of the frost and snow, but since Calgary weather is “changeable” you need to be ready to move either way.
Last year, we planted before the May long weekend and it snowed in late May. Remember that? Well that day of snow and lows in the negatives killed our tender cucumber and pepper plants. So this year, we're doing our planting in two stages.
We recently planted potatoes, radishes, parsnips, carrots, beets, lettuce, onions and peas. All of those can take a light frost. However we are holding off on planting the pumpkins, melons, peppers and tomatoes. While it was 27 degrees and sunny earlier this week, the long weekend and the following week looks suspiciously sketchy with lots of rain and lows in the +2 area. We need temps above +5 at night before we can plant our tender veggies.
The image above is a close-up of our rows. We planted a row of radishes and then a row of parsnips. Why? Parsnips take 100 – 120 days to mature while radishes mature in 45 – 50 days. That means by the time the radishes are done, we can pull them out of the ground leaving plenty of room for the parsnips to mature. We're essentially using the same ground for two plants, maximizing our harvest from a small urban area.
Here is another little hint for any would be urban gardeners. When you grow vegetables from seed and keep them inside for the first 4 – 6 weeks, the lack of wind and climate controlled conditions makes the plants extremely tender. So carefully harden them off, by placing them outside during the day in a somewhat shady spot for at least a week. That will help the plants develop some stem strength and also get ready for less than ideal growing conditions.