The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By looking at the USDA zone info for Frederick you should be able to estimate when it's possible to plant primula.

Planting Calendar for Primula

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

Primula are very cold tolerant which tells us that you can start planting them much earlier than more sensitive plants.

The earliest that you can plant primula in Frederick 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. If you wait any later than that and your primula may not have a chance to really do well. You can get started a little bit earlier by starting your primula indoors.

Last Frost Date

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

Since the USDA zone info for Frederick may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Frederick you get a frost after April 15 so just be sure to be ready to protect your primula if you have a late frost.

USDA Zone Info for Frederick

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 Frederick

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