One of the best tools that you have as gardeners to help us figure out 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.

In Oregon you can determine when it's possible to plant alternanthera by reviewing the USDA zone info.

Planting Calendar for Alternanthera

Frost tolerance for alternanthera:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since alternanthera are not cold tolerant you need to wait until after the last frost before you can plant them.

The earliest that you can plant alternanthera in Oregon 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 alternanthera and expect a good harvest is probably August. If you wait any later than that and your alternanthera may not have a chance to really do well. You can get started a few weeks earlier by starting your alternanthera indoors.

Last Frost Date

In Oregon the average date of last frost happens on April 15. You should expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Oregon is just an average the actual date of last frost is different every year. Half of the time in Oregon there is a last frost after April 15 so be sure to be ready to cover your alternanthera in the event of a late frost.

USDA Zone Info for Oregon

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Oregon

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