One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Walla Walla it's a good idea to figure out when you can plant alstromeria.

Planting Calendar for Alstromeria

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

Since alstromeria are moderately cold tolerant you can plant them just a bit earlier in the year than other frost tender plants.

The earliest that you can plant alstromeria in Walla Walla 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 alstromeria and expect a good harvest is probably September. You probably don't want to wait any later than that or else your alstromeria may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your alstromeria indoors.

Last Frost Date

In Walla Walla the average date of last frost happens on April 15. In the coldest months of winter you can expect an average low temperature of 0°F.

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Walla Walla and it is different every year. Half of the time in Walla Walla last frost occurs after April 15 so be sure to be ready to cover your alstromeria in the event of a surprise late frost.

USDA Zone Info for Walla Walla

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 Walla Walla

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