One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Waterloo should be reviewed to determine when it's a good idea to plant catharanthus.

Planting Calendar for Catharanthus

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

Catharanthus are not cold tolerant which tells us 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 Waterloo 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. You probably don't want to wait any later than that or else your catharanthus may not have a chance to fully mature. If you are starting your catharanthus indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Waterloo. It might get as low as -5°F during the coldest months of winter.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Waterloo and it can change quite a bit from year to year. Since half of the time in Waterloo you get surprised by a frost after April 15 be ready to cover your catharanthus in the event of one of those late frosts.

USDA Zone Info for Waterloo

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Waterloo

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