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

The USDA zone info for Idaho Falls can be looked at to figure out when 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.

You can plant primula quite a bit earlier in the year because they do well in cold.

The earliest that you can plant primula in Idaho Falls 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 really do well. Starting your primula indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Idaho Falls. In the coldest months of winter you can expect an average low temperature of -20°F.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Idaho Falls and it is different every year. Half of the time in Idaho Falls you get surprised by a frost after April 15 so always be ready to cover your primula in the event of a surprise late frost.

USDA Zone Info for Idaho Falls

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 Idaho Falls

You may be interested in your other planting guides for Idaho Falls.