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

In Derby you can figure out when it's possible to plant primula by referring to the USDA zone info.

Planting Calendar for Primula

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

Primula can survive in cold weather which means that you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant primula in Derby 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 primula and expect a good harvest is probably September. You probably don't want to wait any later than that or else your primula may not have a chance to grow to maturity. Starting your primula indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Derby. It might get as low as -5°F during the coldest months of winter.

Since the USDA zone info for Derby is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Derby you get a frost after April 15 so always be ready to cover your primula in the event of a late frost.

USDA Zone Info for Derby

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 Derby

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