One of the first steps you take when you are figuring out 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.

You should be able to estimate when it's possible to plant impatiens by using the USDA zone info for Denver.

Planting Calendar for Impatiens

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

You really shouldn't plant impatiens until after the last frost because they are not cold tolerant.

The earliest that you can plant impatiens in Denver 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. You probably don't want to wait any later than that or else your impatiens may not have a chance to grow to maturity. You can get started a little bit earlier by starting your impatiens indoors.

Last Frost Date

On average the last frost is on April 15 in Denver. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Denver is just an average the actual date of last frost will vary from year to year. Half of the time in Denver last frost occurs after April 15 so make sure that you are ready to cover your impatiens in the event of a late frost.

USDA Zone Info for Denver

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°F

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Denver

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