Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to figure out when it's a good idea to plant tree onions by reviewing the USDA zone info for Mount Rainier.

Planting Calendar for Tree onions

Frost tolerance for tree onions:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Tree onions do ok in mild cold which tells us that you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant tree onions in Mount Rainier is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant tree onions and expect a good harvest is probably August. Any later than that and your tree onions may not have a chance to grow to maturity. You can get started a little bit earlier by starting your tree onions indoors.

Last Frost Date

In Mount Rainier the average date of last frost happens on April 15. You can expect an average low temperature of 0°F in the coldest months of winter.

Remember that USDA zone info for Mount Rainier is not always accurate and the actual date of last frost changes from year to year. Since half of the time in Mount Rainier it frosts late in the year after April 15 be ready to protect your tree onions if you have a surprise late frost.

USDA Zone Info for Mount Rainier

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 Mount Rainier

You may be interested in your other planting guides for Mount Rainier.