Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of getting a good idea when to plant impatiens is to consult the USDA zone info for Sterling.

Planting Calendar for Impatiens

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

Impatiens are not cold tolerant which tells us that you have to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant impatiens in Sterling 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. If you are starting your impatiens indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Sterling may not be accurate from year to year the actual date of last frost changes from year to year. Since half of the time in Sterling it frosts late in the year after April 15 be ready to cover your impatiens in the event of a late frost.

USDA Zone Info for Sterling

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 Sterling

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