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

A way of making a decision about when it's a good idea to plant dahlia is to use the USDA zone info for Sun Prairie.

Planting Calendar for Dahlia

Frost tolerance for dahlia:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

You should not plant dahlia until after all chance of frost has passed because they require warm weather.

The earliest that you can plant dahlia in Sun Prairie 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 dahlia and expect a good harvest is probably August. You probably don't want to wait any later than that or else your dahlia may not have a chance to grow to maturity. Starting your dahlia indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Sun Prairie the average date of last frost happens on April 15. You can expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Sun Prairie is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Sun Prairie it frosts late in the year after April 15 be ready to cover your dahlia if you have one of those late frosts.

USDA Zone Info for Sun Prairie

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 Sun Prairie

You may be interested in your other planting guides for Sun Prairie.