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.

It's a good idea to estimate when it's possible to plant regal geranium by referring to the USDA zone info for Zone 4b.

Planting Calendar for Regal Geranium

Frost tolerance for regal geranium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Regal Geranium do well in very little cold which means that you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant regal geranium in Zone 4b 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 regal geranium and expect a good harvest is probably August. Any later than that and your regal geranium may not have a chance to fully mature. You can get started a little bit earlier by starting your regal geranium indoors.

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.

Keep in mind that USDA zone info for Zone 4b is an average and the actual date of last frost will vary from year to year. Since half of the time in Zone 4b you get surprised by a frost after May 15 be ready to protect your regal geranium if you have a surprise late frost.

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.