The Dirt On When To Plant

Now that Spring is on its way, dedicated gardeners are anxious to get outside and get in the dirt. But really, when is it time to plant your garden and flowers?

The old axiom among gardeners was that the time to plant your garden was the May 24th weekend. Is this still true in the age of “global warming” and “climate change”? Like most things in life, the answer is complicated.

We should remember that when this saying originated, most gardens were grown from seed. In general, seeds need the ground to be warm in order to germinate. Planting too early, before the ground has warmed up (20C) can mean that the seeds will just sit there and perhaps, rot in the ground. So, in general the 24th of May is still a pretty good rule of thumb for planting seeds out of doors in Eastern Ontario. Further north, a week or two later is generally advised and, in southwestern Ontario, a couple of weeks earlier is usually possible.

Some of the exceptions to this are the so-called “cold weather crops”. Peas and lettuce for example, can be planted as soon as the ground is dry enough to work. These crops dislike the hot, hot days of summer but thrive in the cooler wetter conditions of spring. The other advantage of growing cold weather crops is that after harvest you can plant some of the heat loving crops and get two harvests from the same ground!

However, (I told you it was complicated) most of us don’t just plant seeds. We buy annual seedlings already growing and even flowering. When should these be planted?

Generally, the same rule applies. If the ground isn’t warm enough to stimulate growth, rot or fungal infections can set in. With our busy lives, most flower gardeners today, are not patient people! We want to plant our flowers and see the blooms today! With this in mind, it is important to remember that these seedlings and mature annuals we get from the garden centre have led very pampered lives. They were grown in ideal climate controlled conditions – warm and watered and fed and protected from nasty old Mother Nature. Many of the flowers we plant are from tropical and semi-tropical areas of the world. To suddenly set them out in your Ontario garden, exposed and on their own, can be a real shock. (It’s like coming home from that Florida vacation in February!).

There are several things you can do to minimize the shock. First of all, pick healthy plants. Don’t worry about the blooms. Look for healthy stems and roots. Don’t plant them in the ground right away. Set them outside in a sheltered location for a few days and let them gradually get used to being outside. When you plant, pinch the flowers off. You want each plant to devote its energy to establishing roots. The flowers will come later. Water each plant thoroughly when they are planted. This makes sure that the roots are in contact with the soil and air pockets are eliminated.

Perennials are a different story. They are actually conditioned for our climate and can be planted almost any time of the year. I prefer to plant perennials in the fall but, I hardly ever do- something else seems to come up. If they are field-grown perennials, just put them in a well-prepared bed and water. If they have been raised and kept inside green houses, I would try to harden them up before planting.

As you can see, the answer is really, “It depends”!