Before planting it is a good idea to find your USDA Zone info to determine 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 you can plant pumpkins is to examine the USDA zone info for Ottawa.

Planting Calendar for Pumpkins

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

Pumpkins are not cold tolerant which tells us that it is important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant pumpkins in Ottawa is April. However, you really should wait until May if you don't want to take any chances.

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

Last Frost Date

In Ottawa the average date of last frost happens on April 15. You can expect an average low temperature of -15°F in the coldest months of winter.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Ottawa and it is different every year. Since half of the time in Ottawa there is a last frost after April 15 be ready to protect your pumpkins if you have a late frost.

USDA Zone Info for Ottawa

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 Ottawa

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