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.

The first opportunity to plant dahlia in Collinsville should be figured out by checking out the USDA zone info.

Planting Calendar for Dahlia

Frost tolerance for dahlia:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since dahlia are not cold tolerant it's important to wait until after the last frost before you can plant them.

The earliest that you can plant dahlia in Collinsville 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. If you wait any later than that and your dahlia may not have a chance to really do well. If you are starting your dahlia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Collinsville the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of -5°F.

Since the USDA zone info for Collinsville is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Collinsville there is a last frost after April 15 be ready to protect your dahlia in the event of a late frost.

USDA Zone Info for Collinsville

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 Collinsville

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