Gardening Tips: Listen to Your Lilacs

Editor’s Note: This column first appeared on 16 May 2018 but I suspect the picture of the lilacs in full bloom was from the previous spring.


What to do this week

There is an old folk saying that one should not plant summer crops until the lilacs and apple trees are in full bloom. Cold, hardy crops are different. You can certainly plant things like onions, spinach, peas and kale this time of year (or earlier) but tomato, pepper, squash, eggplant, corn and all other warm weather crops should not be planted yet, no matter how nice it is at 2:00 in the afternoon. Even the hardy crops should not be planted until your soil is dry from the spring thaw, or seeds could just rot, although we seem to be mostly past that now.

Lilacs 18 May 2022

Where we are… (Spectator photo)

The biggest danger, other than soggy soil, is frost. As you continue to garden you will develop a skill that allows you to predict frost in the micro-climate of your garden, and take protective measures. This is especially useful if you don’t have lilac or apple trees.

The days recently have been lovely, but you may be asleep and not notice that it can get very cold at night still. Frost can kill. This morning it was -3 degrees Celsius in Margaree and +3 degrees Celsius in Sydney at dawn, so you can’t just go by the generic Cape Breton weather forecast you are likely to get from the media. You have to get to know your own garden. Here are a few tips that will help you to develop that predictive skill you will need to prevent loss from frost.

Lower lying areas are more subject to frost. The cold air settles into them. Areas open to breezes are less likely to get frost. (Some large farms in Ontario and the US actually use big wind-making fans to prevent frost over large areas!) If you have a hedge or a windbreak, make sure it has some gaps to allow the cold air to drain downhill.

When it comes to night frosts, humidity is good, it the warmth of the day, as do clouds. If there is some talk of frost in your area, and it is a clear, dry, star-filled night, you are more likely to have to take action than on a damp and cloudy night.

Things can change quickly as the day progresses. It is a good idea to take a stroll in the garden around 9:00 in the evening. By then you will be able to tell if it is windy or still, damp or dry. If you are really worried it might be a good idea to try to cover your crops, or even to water. I would not normally recommend watering at night, but there are times it could help. In a pinch, you could cover your rows with old blankets. Don’t water the blankets, as they will weigh too heavily on the plants and make contact with the leaves. That is another danger: contact between the leaves and a cold object, even if that object is intended to protect. I had a bit of a problem the other day with my fig trees. They are still safely in the greenhouse, but I noticed that a few leaves were in contact with the glass. They froze. Luckily, the rest of the tree is fine.

Lilacs (Spectator photo)

Where we’re heading… (Spectator photo)

If you like to play backyard scientist, you can make or buy a sling psychrometer. In its simplest form, it is two thermometers tied together, one of them partially wrapped in a cloth you can moisten. You swing that around by the string for a few minutes and then check the difference in temperature between the dry and wet readings. There are lots of YouTube videos on the many readings you can calculate from this experiment, but I’ll just tell you about one. If you check the wet reading around 9:00PM and it is 2 degrees Celsius or less, you are very likely to get frost that night. Get out the old blankets!

Better still, don’t plant your warm crops until the lilacs and apple trees are in full blossom. It may be just an old folk saying, or it may be that trees have been around long enough to have the sense to wait until conditions in your yard are ready to get to work producing food. Follow their lead.





Market gardener, farmer, workshop leader, seed-saver, political candidate and mother, Michelle Smith has spent over 30 years coping with the challenges of our bioregion and in the process has built a store of practical and technical knowledge. The Inverness resident has served on the board of Seeds of Diversity Canada and represented Alternative Producers with the Federation of Agriculture but can do nothing about her hair. She is pictured with a head of Club Wheat, a seed that shares her approach to hairdressing.




Backyard food gardener Madeline Yakimchuk caught the food-security bug in the early ’90s through Cuba’s Urban Agriculture Department, taking her first permaculture course and planting her first garden. She can often be found discussing food security, nurturing a plant-based lifestyle or trying to give away vegetables. Professionally, she is GRYPHON media productions but sometimes uses la bruja in her volunteer work, most notably in managing the garden column, which begins life as a telephone interview.