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.

A way of estimating when it's possible to plant dahlias is to consult the USDA zone info for Riverdale.

Planting Calendar for Dahlias

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

Since dahlias require warm weather it's important to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant dahlias in Riverdale 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. If you wait any later than that and your dahlias may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your dahlias indoors.

Last Frost Date

In Riverdale the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 10°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 Riverdale and it can change quite a bit from year to year. Half of the time in Riverdale you get a frost after March 15 so make sure that you are prepared to cover your dahlias in the event of a surprise late frost.

USDA Zone Info for Riverdale

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Riverdale

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