Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of determining when it's the best time to plant lithospermum is to look at the USDA zone info for Ontario.

Planting Calendar for Lithospermum

Frost tolerance for lithospermum:	Not tolerant of frost.
When to plant:	After the last frost.

Lithospermum do not do well in cold weather which tells us that you need to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant lithospermum 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 lithospermum and expect a good harvest is probably September. Any later than that and your lithospermum may not have a chance to fully mature. You can get started a few weeks earlier by starting your lithospermum indoors.

Last Frost Date

The average date of last frost is January 31 in Ontario. It might get as low as 30°F during the coldest months of winter.

Keep in mind that USDA zone info for Ontario may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Ontario you get surprised by a frost after January 31 so always be ready to cover your lithospermum if you have 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.