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.

You will be able to determine when it's a good idea to plant geranium by looking at the USDA zone info for Zone 4b.

Planting Calendar for Geranium

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

Since geranium are not cold tolerant it's necessary to wait until after the last frost has passed before you can plant them.

The earliest that you can plant geranium in Zone 4b is May. However, you really should wait until June if you don't want to take any chances.

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

Last Frost Date

In Zone 4b the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Zone 4b is just an average the actual date of last frost changes from year to year. Since half of the time in Zone 4b it frosts late in the year after May 15 be ready to protect your geranium if you have one of those late frosts.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.