One of the first steps you take when you are figuring out your gardening schedule is find your 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.

A way of getting a good idea when it's a good idea to plant pennyroyal is to examine the USDA zone info for Edinburgh.

Planting Calendar for Pennyroyal

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

Pennyroyal do ok in a bit of cold which means that you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant pennyroyal in Edinburgh 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. You can get started a few weeks earlier by starting your pennyroyal indoors.

Last Frost Date

The average date of last frost is April 15 in Edinburgh. In the coldest months of winter you should expect an average low temperature of -10°F.

Since the USDA zone info for Edinburgh is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Edinburgh you get a frost after April 15 be ready to cover your pennyroyal in the event of a surprise late frost.

USDA Zone Info for Edinburgh

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 Edinburgh

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