One of the first steps you take when you are making a decision about 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.

By reviewing the USDA zone info for Polson you should be able to figure out when it's possible to plant osteospermum.

Planting Calendar for Osteospermum

Frost tolerance for osteospermum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Osteospermum are one of those plants that can tolerate a little bit of cold weather which tells us that you can get them planted earlier than more sensitive plants.

The earliest that you can plant osteospermum in Polson is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant osteospermum and expect a good harvest is probably September. You probably don't want to wait any later than that or else your osteospermum may not have a chance to fully mature. Starting your osteospermum indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Polson. It might get as low as -10°F during the coldest months of winter.

Since the USDA zone info for Polson is an average the actual date of last frost is different every year. Since half of the time in Polson it frosts late in the year after April 15 be ready to protect your osteospermum in the event of one of those late frosts.

USDA Zone Info for Polson

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Polson

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