The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's a good idea to figure out when it's possible to plant marigold by referring to the USDA zone info for Ontario.

Planting Calendar for Marigold

Frost tolerance for marigold:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since marigold are not cold tolerant you need to wait until after the last frost before you can plant them.

The earliest that you can plant marigold in Ontario is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant marigold and expect a good harvest is probably September. Any later than that and your marigold may not have a chance to fully mature. If you are starting your marigold indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on January 31 in Ontario. In the coldest months of winter you can expect an average low temperature of 30°F.

Just be sure to remember that USDA zone info for Ontario is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Ontario you get surprised by a frost after January 31 so just be sure to be ready to cover your marigold in the event of one of those late frosts.

USDA Zone Info for Ontario

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Ontario

You may be interested in your other planting guides for Ontario.