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.

A common way of determining when it's possible to plant dahlias is to refer to the USDA zone info for Idaho Falls.

Planting Calendar for Dahlias

Frost tolerance for dahlias:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Dahlias do not do well in cold weather which tells us that you need to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant dahlias in Idaho Falls 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 dahlias and expect a good harvest is probably August. You probably don't want to wait any later than that or else your dahlias may not have a chance to fully mature. If you are starting your dahlias indoors then you might be able to get away with starting them 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 should expect an average low temperature of -20°F.

Since the USDA zone info for Idaho Falls is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Idaho Falls last frost occurs after April 15 be ready to protect your dahlias in the event of one of those late frosts.

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.