One of the first steps you take when you are estimating 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.

In Portland you can estimate when to plant osteospermum by checking out the USDA zone info.

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 start planting them earlier than other plants that might not handle the cold.

The earliest that you can plant osteospermum in Portland 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. Starting your osteospermum indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Portland. In the coldest months of winter you should expect an average low temperature of 0°F.

Just be sure to remember that USDA zone info for Portland is not always accurate and the actual date of last frost can change quite a bit from year to year. Half of the time in Portland it frosts late in the year after April 15 so always be ready to protect your osteospermum if you have a surprise late frost.

USDA Zone Info for Portland

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Portland

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