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

By reviewing the USDA zone info for Oswego you will be able to figure out when it's a good idea to plant pennyroyal.

Planting Calendar for Pennyroyal

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

You can plant pennyroyal a lot earlier in the year because they are one of those plants that can tolerate quite a bit of cold weather.

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

Last Frost Date

The average date of last frost is April 15 in Oswego. In the coldest months of winter you should expect an average low temperature of -15°F.

Keep in mind that USDA zone info for Oswego is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Oswego last frost occurs after April 15 so always be ready to cover your pennyroyal if you have a surprise late frost.

USDA Zone Info for Oswego

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 Oswego

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