Why wait until May Two-Four? Let’s plant now
Herbs, including basil and parsley, should be “hardened off” before they are planted outdoors.
A little bit of knowledge can be a useful thing.
Many Canadian gardeners wait to plant and sow until Victoria Day, the May TwoFour long weekend — named in honour of Queen Victoria’s birthday, and not so much in celebration of a large case of beer.
But there is no need for this delay. Fact is, you can be out there this weekend, frolicking on the lawn and digging in the garden if you have the right bit of knowledge. That is where we come in.
Let’s start with this: On May 9, this Saturday, it is OK to plant and sow anything that is frosthardy. It is not, however, a good idea to plant anything that is frost-sensitive.
Hardy 101: The tipping point for many plants is a 0C temperature, which is not to suggest that you should plant your tomatoes if the next few weeks are frost free. The soil at this time of year is cold, and plants that prefer warm soil don’t like that one little bit. Wait until the May long weekend, at the earliest, to plant out frosttender plants.
Conversely there are plants that thrive in cool soil and cool air temperatures.
Here’s what you can plant now:
Veggies: sow directly in the ground the seeds of carrots, onions, leeks, lettuce, cabbage, all “cole crops,” — for instance, broccoli, cabbage, kale, cauliflower — beets, peas and Swiss chard.
Vegetable plants are now available at many garden retailers — for curbside pickup — and we encourage you to plant them out. All the plants mentioned above, except the root crops, will grow nicely from seedling plants. The root crops mentioned should be sown from seed directly into the soil.
As well, raspberries, strawberries, rhubarb and all fruitbearing shrubs, including currants and blackberries, are safe to plant out now.
Speaking of edibles, many herbs can be planted out but only after you harden them off by introducing them to midday sun and cold evening temperatures, expanding their time out of doors by an hour or two a day. As the plants become used to the lower temperatures and direct sun, they acclimatize to the outdoor environment. After about 10 days, they are safe to plant out.
Ornamentals are ready for planting now, too. All flowering shrubs, trees (including fruit trees), evergreens, roses and most perennials are suitable for early May planting. The exceptions are those that have been force-grown in a greenhouse. You will know these right away: they’re the ones with the new, green growth, which is soft and susceptible to frost damage.
These ornamentals plants are also the most tempting to buy, which is why they are forcegrown.
Flowering plants that are perfectly hardy and ready to plant today include pansies, violas, ranunculus, mums and all flowering bulbs including crocuses, daffodils, hyacinths and tulips.
It is open season for lawns. Go ahead: Rake, sow seed and fertilize to your heart’s content. You can’t go wrong. Lawns are a cold crop.
What not to plant/sow: There are many plants that are sensitive to frost and cold soil. These should not be planted until late in May or early June.
The veggies in this category include tomatoes, potatoes, peppers, squash, beans, cucumbers, melons and corn. When soil temperatures rise above 15C, you can plant or sow these crops.
You will also need to wait to plant annual flowering plants (called “annuals” since they complete their life cycle in one growing season) and these include — but are not limited to — petunias, impatiens, geraniums and snapdragons.
It is interesting to note that many of them will survive early frost well into November — geraniums, dusty miller and snapdragons to mention just three. As the autumn temperatures drop slowly over days and weeks, these plants become acclimatized and adapt to light frost.
A little knowledge, a little mystery dispelled. You are welcome.
Mark and Ben Cullen are expert gardeners and contributors for the Star. Follow Mark on Twitter: @MarkCullen4