One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Washington can be read to determine when it's possible 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 quite a bit earlier in the year because they do well in cold.

The earliest that you can plant pennyroyal in Washington 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 really do well. Starting your pennyroyal indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Washington the average date of last frost happens on April 15. It might get as low as -5°F during the coldest months of winter.

Keep in mind that USDA zone info for Washington is an average and the actual date of last frost will vary from year to year. Half of the time in Washington it frosts late in the year after April 15 so make sure that you are prepared to protect your pennyroyal in the event of a surprise late frost.

USDA Zone Info for Washington

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Washington

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