One of the best tools that you have as gardeners to help us figure out 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.

In Cambridge you can determine when to plant scarlet pimpernels by using the USDA zone info.

Planting Calendar for Scarlet Pimpernels

Frost tolerance for scarlet pimpernels:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Scarlet Pimpernels do ok in moderate cold which tells us that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant scarlet pimpernels in Cambridge 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 scarlet pimpernels and expect a good harvest is probably August. Any later than that and your scarlet pimpernels may not have a chance to fully mature. Starting your scarlet pimpernels indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Cambridge the average date of last frost happens on May 15. It might get as low as -30°F during the coldest months of winter.

Since the USDA zone info for Cambridge is an average the actual date of last frost will vary from year to year. Half of the time in Cambridge it frosts late in the year after May 15 so just be sure to be ready to protect your scarlet pimpernels if you have a surprise late frost.

USDA Zone Info for Cambridge

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Cambridge

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