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 using the USDA zone info for Alton it's possible to determine when it's the best time to plant cleome.

Planting Calendar for Cleome

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

Cleome require warm weather which means that it is necessary to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant cleome in Alton 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 cleome and expect a good harvest is probably August. If you wait any later than that and your cleome may not have a chance to fully mature. Starting your cleome indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Alton. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Alton is an average the actual date of last frost is different every year. Half of the time in Alton there is a last frost after April 15 so make sure that you are prepared to protect your cleome in the event of one of those late frosts.

USDA Zone Info for Alton

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Alton

You may be interested in your other planting guides for Alton.