One of the best tools that you have as gardeners to help us figure out 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.

By checking out the USDA zone info for Zone 4a it's a good idea to figure out when it's a good idea to plant regal geranium.

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 can survive in some cold which means that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant regal geranium in Zone 4a 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 grow to maturity. If you are starting your regal geranium indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Zone 4a. You can expect an average low temperature of -30°F in the coldest months of winter.

Always keep in mind that USDA zone info for Zone 4a is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Zone 4a you get a frost after May 15 so always be ready to cover your regal geranium if you have one of those late frosts.

USDA Zone Info for Zone 4a

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Zone 4a

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