Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant impatiens in Longmont should be determined by referring to the USDA zone info.

Planting Calendar for Impatiens

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

It's probably not a good idea to plant impatiens until after all chance of frost has passed because they do not do well in cold weather.

The earliest that you can plant impatiens in Longmont 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 fully mature. 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

On average the last frost has passed is on April 15 in Longmont. You can expect an average low temperature of -15°F in the coldest months of winter.

It's important to remember that USDA zone info for Longmont may not be accurate from year to year and the actual date of last frost can change quite a bit from year to year. Since half of the time in Longmont it frosts late in the year after April 15 be ready to protect your impatiens if you have a surprise late frost.

USDA Zone Info for Longmont

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 Longmont

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