One of the first steps you take when you are getting a good idea 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.

In Keokuk you can figure out when to plant catharanthus by checking out the USDA zone info.

Planting Calendar for Catharanthus

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

Catharanthus do not do well in cold weather which means that it's important to wait until it warms up after the last frost has passed before you can plant them.

The earliest that you can plant catharanthus in Keokuk 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 grow to maturity. Starting your catharanthus indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Keokuk. It might get as low as -10°F during the coldest months of winter.

Remember that USDA zone info for Keokuk is just an average and the actual date of last frost will vary from year to year. Since half of the time in Keokuk it frosts late in the year after April 15 be ready to cover your catharanthus in the event of a late frost.

USDA Zone Info for Keokuk

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 Keokuk

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