One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant napa cabbage in Ottawa should be estimated by using the USDA zone info.

Planting Calendar for Napa cabbage

Frost tolerance for napa cabbage:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Napa cabbage can survive in quite a bit of cold which tells us that you can plant them much earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant napa cabbage in Ottawa 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 napa cabbage and expect a good harvest is probably September. Any later than that and your napa cabbage may not have a chance to grow to maturity. If you are starting your napa cabbage indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Ottawa. You can expect an average low temperature of -10°F in the coldest months of winter.

Remember that USDA zone info for Ottawa is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Ottawa you get surprised by a frost after April 15 so make sure that you are prepared to cover your napa cabbage if you have a late frost.

USDA Zone Info for Ottawa

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Ottawa

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