Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when you can plant primula is to examine the USDA zone info for Zone 5a.

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 tells us that you can plant them earlier in the year than more sensitive plants.

The earliest that you can plant primula in Zone 5a 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. Starting your primula indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Zone 5a. In the coldest months of winter you can expect an average low temperature of -20°F.

Just be sure to remember that USDA zone info for Zone 5a is not always accurate and the actual date of last frost can change quite a bit from year to year. Since half of the time in Zone 5a you get surprised by a frost after April 15 be ready to cover your primula if you have one of those late frosts.

USDA Zone Info for Zone 5a

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Zone 5a

You may be interested in your other planting guides for Zone 5a.