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 Riverdale you will be able to estimate when 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.

You can plant osteospermum a little earlier in the year because they do well in moderate cold.

The earliest that you can plant osteospermum in Riverdale 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. If you wait any later than that and 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 few weeks earlier.

Last Frost Date

In Riverdale the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 10°F.

Since the USDA zone info for Riverdale may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Riverdale it frosts late in the year after March 15 so make sure that you are prepared to cover your osteospermum if you have a surprise late frost.

USDA Zone Info for Riverdale

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Riverdale

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