Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. 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 determine when it's a good idea to plant salpiglossis by using the USDA zone info for Longmont.

Planting Calendar for Salpiglossis

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

It's not a good idea to plant salpiglossis until after the last frost because they are not cold tolerant.

The earliest that you can plant salpiglossis 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 salpiglossis and expect a good harvest is probably August. Any later than that and your salpiglossis may not have a chance to grow to maturity. If you are starting your salpiglossis indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

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

Keep in mind that USDA zone info for Longmont may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Longmont you get a frost after April 15 be ready to cover your salpiglossis if you have one of those late frosts.

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.