Many locations on the east coast of Canada and the USA have had frost warnings the past few nights with more to come for the next few days. Some annuals tolerate a light frost, others not so much. Of course, the first frost date varies across the globe, sometimes year to year within the same area.
In other words, frost is unpredictable.
You can extend the season on both ends by heeding frost warnings in your weather forecast. In the spring I tend to start my containers early to ensure I get the annuals I want. If a frost warning is issued, I move the containers into my garage, off the (cold) cement floor, for the night in question. The same technique can be used in the fall when a sporadic early frost is in the forecast.
These are ways you can protect your annuals.
Sheets, Towels, Tablecloths, and even Plastic
Beds of annual (those that you have to plant each spring) flowers can be protected with bed sheets, towels, or even tablecloths. I get the cheap tablecloths from a dollar store, the ones with the felt-like backing; they work great. Sticks or stakes can be used to prevent the covering from crushing the plants, and rocks to hold the covering down so they don’t blow in the wind.
Plastic garbage bags work too and often fit right over containers, just ensure they reach right to the ground. And again, use rocks to hold them in place. Or tie something around the base to hold the plastic in place; burlap works well here too. As do large tarps, although they can be heavy but work great on raised beds with tiny seedlings. If plants are taller, simply add stakes around the plants to keep the tarp off them.
Of course, whatever you use will depend on the size of the beds or containers you wish to protect.
Yes, frost covers are a thing sold in garden centers, nurseries, big stores, and even on Amazon. I’ve never tried any of these options, if you have please let me know how you like them!
A Warmer Spot
If you have annuals in pots or still in their nursery containers waiting to be planted, simply move them to a garage or basement for frost warnings. If in an unheated garage, store them on something so they are not on the cement floor. A shelf or even storage bins work well. Then you can move them in and out depending on the weather.
If you have lots, a wheelbarrow or cart works well to transport them back and forth. You could even leave the tender plants in whatever you use in the garage.
My yet-unplanted annual collection stayed in my garage all day yesterday as the temperature here never reached double digits before another frost warning last night.
Don’t Worry About Perennials in Frost Warnings
While annuals will be affected by frost, most perennials will not. Perennials can be planted as soon as the ground is thawed and will survive the temperature fluctuations in spring and fall.
Perennials can overwinter in containers too if you choose plants two zones hardier than what is normally hardy in your area. Otherwise, you can stick them in the ground to overwinter, to use them again the following spring.