One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

By looking at the USDA zone info for Bethalto it's a good idea to figure out when it's the best time to plant catharanthus.

Planting Calendar for Catharanthus

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

It's probably a bad idea to plant catharanthus until after the last frost when the weather gets warmer because they require warm weather.

The earliest that you can plant catharanthus in Bethalto 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 catharanthus and expect a good harvest is probably August. Any later than that and your catharanthus may not have a chance to fully mature. You can get started a few weeks earlier by starting your catharanthus indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Bethalto. In the coldest months of winter you should expect an average low temperature of -10°F.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Bethalto and it changes from year to year. Since half of the time in Bethalto it frosts late in the year after April 15 be ready to protect your catharanthus in the event of a surprise late frost.

USDA Zone Info for Bethalto

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 Bethalto

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