The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By using the USDA zone info for Mercer Island you should be able to determine when it's the best time to 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 one of those plants that can tolerate a little bit of cold weather you can plant them just a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant alstromeria in Mercer Island 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 really do well. Starting your alstromeria indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Mercer Island and it can change quite a bit from year to year. Half of the time in Mercer Island you get surprised by a frost after March 15 so make sure that you are ready to protect your alstromeria in the event of a late frost.

USDA Zone Info for Mercer Island

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 Mercer Island

You may be interested in your other planting guides for Mercer Island.