Although many gardeners here in Alberta "put the garden in" on the May long weekend, there are many kinds of vegetables that can be seeded in the garden much earlier, saving you the trouble of growing seedlings indoors and transplanting. For example, broccoli, beets, cabbage, Swiss chard, leaf lettuce, onions, peas, radishes, rutabaga, asparagus, garlic, kale, kohlrabi, leeks, turnips, parsnips and spinach can all be planted well before your last frost date. In fact, some seeding instructions will tell you to plant as soon as the soil can be worked. What does that mean?
Your soil is not ready to plant in if it is too wet. Working in wet soil compacts it, destroying the air spaces that are necessary for plant roots to grow in. Many prairie gardeners have clay soil which, although rich in nutrients, takes a long time to dry out in the spring and becomes very hard if it is compacted. To test soil for readiness, you could simply step in your garden and see if you leave wet footprints, or walk away with mud on your shoes. If you do, the soil is too wet. If you don't want muddy shoes, dig down a couple of inches and grab a handful of soil. If it easily squeezes into a round ball, it's too wet. It is ready for planting if it has a crumbly texture, instead.
If planting early in the spring doesn't sound like a fun idea, consider planting in the fall instead. When cleaning the garden up in the fall, prepare the beds as you would in the spring, and plant the spring seeds as close to the first snowfall as possible. This, of course, is a bit of a guessing game, but you don't want to plant them so early that they start to grow during a warm fall, and then die with the first hard frosts. Sow the seeds thicker than normal. They will usually lie dormant under the snow all winter, then sprout at just the right time in the spring! That's what I hear, anyway, but I've never been organized enough to try it myself.