One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Granite City you can estimate when to plant diascia by using the USDA zone info.

Planting Calendar for Diascia

Frost tolerance for diascia:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Diascia do ok in moderate cold which means that you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant diascia in Granite City is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant diascia and expect a good harvest is probably September. You probably don't want to wait any later than that or else your diascia may not have a chance to grow to maturity. If you are starting your diascia indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Granite City. You can expect an average low temperature of -5°F in the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Granite City and it is different every year. Since half of the time in Granite City you get a frost after April 15 be ready to cover your diascia in the event of a surprise late frost.

USDA Zone Info for Granite City

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 Granite City

You may be interested in your other planting guides for Granite City.