One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can determine when it's the best time to plant cleome in Zone 4b by using the USDA zone info.

Planting Calendar for Cleome

Frost tolerance for cleome:	Not tolerant of frost.
When to plant:	After the last frost.

Cleome are not cold tolerant which means that it's necessary to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant cleome 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 cleome and expect a good harvest is probably August. Any later than that and your cleome may not have a chance to grow to maturity. You can get started a little bit earlier by starting your cleome indoors.

Last Frost Date

The average date of last frost is May 15 in Zone 4b. You can expect an average low temperature of -25°F in the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Zone 4b and it can change quite a bit from year to year. Since half of the time in Zone 4b last frost occurs after May 15 be ready to protect your cleome in the event of a 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.