The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A common way of determining when it's possible to plant alternanthera is to use the USDA zone info for Washington.

Planting Calendar for Alternanthera

Frost tolerance for alternanthera:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since alternanthera do not do well in cold weather you must wait until after the last frost before you can plant them.

The earliest that you can plant alternanthera in Washington 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 grow to maturity. You can get started a few weeks earlier by starting your alternanthera indoors.

Last Frost Date

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

Since the USDA zone info for Washington is not always accurate the actual date of last frost is different every year. Since half of the time in Washington there is a last frost after April 15 be ready to cover your alternanthera in the event of a late frost.

USDA Zone Info for Washington

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 Washington

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