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.

A way of estimating when it's a good idea to plant catharanthus is to use the USDA zone info for Platteville.

Planting Calendar for Catharanthus

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

Catharanthus require warm weather which tells us that you need to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant catharanthus in Platteville 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. If you wait any later than that and your catharanthus may not have a chance to fully mature. Starting your catharanthus indoors is a great way to get them started a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Platteville. You can expect an average low temperature of -20°F in the coldest months of winter.

Keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Platteville and it will vary from year to year. Since half of the time in Platteville last frost occurs after April 15 be ready to cover your catharanthus if you have one of those late frosts.

USDA Zone Info for Platteville

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Platteville

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