One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Grinnell you can determine when it's the best time to plant dipladenia by checking out the USDA zone info.

Planting Calendar for Dipladenia

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

Dipladenia require warm 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 dipladenia in Grinnell 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 dipladenia and expect a good harvest is probably August. If you wait any later than that and your dipladenia may not have a chance to grow to maturity. Starting your dipladenia indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

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

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Grinnell and it can change quite a bit from year to year. Half of the time in Grinnell it frosts late in the year after April 15 so be sure to be ready to cover your dipladenia if you have a late frost.

USDA Zone Info for Grinnell

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 Grinnell

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