One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of getting a good idea when to plant osteospermum is to use the USDA zone info for River Falls.

Planting Calendar for Osteospermum

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

Since osteospermum are moderately cold tolerant you can plant them just a bit earlier in the year than more sensitive plants.

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

The last month that you can plant osteospermum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your osteospermum may not have a chance to really do well. If you are starting your osteospermum indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In River Falls the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -25°F.

Since the USDA zone info for River Falls is not always accurate the actual date of last frost is different every year. Since half of the time in River Falls there is a last frost after May 15 be ready to cover your osteospermum if you have a surprise late frost.

USDA Zone Info for River Falls

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in River Falls

You may be interested in your other planting guides for River Falls.