The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The USDA zone info for Waterloo should be reviewed to figure out when it's the best time to plant impatiens.

Planting Calendar for Impatiens

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

It's probably not a good idea to plant impatiens until after the last frost because they require warm weather.

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

Last Frost Date

On average all chance of frost has passed is on April 15 in Waterloo. In the coldest months of winter you can expect an average low temperature of -5°F.

Since the USDA zone info for Waterloo is not always accurate the actual date of last frost is different every year. Since half of the time in Waterloo you get surprised by a frost after April 15 be ready to cover your impatiens if you have 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.