Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The first opportunity to plant basil in Zone 4b can be determined by looking at the USDA zone info.

Planting Calendar for Basil

Frost tolerance for basil:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Since basil do not do well in cold weather it is important to wait until after the last frost before you can plant them.

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

Last Frost Date

On average the last frost has passed is on May 15 in Zone 4b. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for Zone 4b may not be accurate from year to year the actual date of last frost changes from year to year. Half of the time in Zone 4b there is a last frost after May 15 so always be ready to protect your basil 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.