One of the first steps you take when you are determining 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.

By looking at the USDA zone info for Galesburg you should be able to estimate 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 has passed.

Since catharanthus are not cold tolerant it is necessary to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant catharanthus in Galesburg 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 little bit earlier by starting your catharanthus indoors.

Last Frost Date

In Galesburg the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Galesburg is not always accurate the actual date of last frost will vary from year to year. Half of the time in Galesburg you get surprised by a frost after April 15 so make sure that you are prepared to protect your catharanthus if you have a late frost.

USDA Zone Info for Galesburg

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Galesburg

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