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

A way of figuring out when you can plant alstromeria is to use the USDA zone info for Tualatin.

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 a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant alstromeria in Tualatin 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 little bit earlier by starting your alstromeria indoors.

Last Frost Date

The average date of last frost is March 15 in Tualatin. You can expect an average low temperature of 15°F in the coldest months of winter.

Always keep in mind that USDA zone info for Tualatin is just an average and the actual date of last frost changes from year to year. Half of the time in Tualatin there is a last frost after March 15 so just be sure to be ready to protect your alstromeria in the event of one of those late frosts.

USDA Zone Info for Tualatin

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

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

Plants to Grow in Tualatin

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