Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of determining when it's a good idea to plant iceberg lettuce is to refer to the USDA zone info for Ontario.

Planting Calendar for Iceberg lettuce

Frost tolerance for iceberg lettuce:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

You can plant iceberg lettuce slightly earlier in the year because they are barely cold tolerant.

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

The last month that you can plant iceberg lettuce and expect a good harvest is probably August. Any later than that and your iceberg lettuce may not have a chance to grow to maturity. Starting your iceberg lettuce indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Ontario. You should expect an average low temperature of -15°F in 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 is different every year. Half of the time in Ontario last frost occurs after April 15 so be sure to be ready to cover your iceberg lettuce if you have one of those late frosts.

USDA Zone Info for Ontario

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Ontario

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