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

A way of estimating when it's possible to plant onions is to consult the USDA zone info for Mammoth Lakes.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Onions can survive in pretty solid cold which tells us that you can plant them quite a bit earlier in the year than other frost tender plants.

The earliest that you can plant onions in Mammoth Lakes 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 onions and expect a good harvest is probably September. If you wait any later than that and your onions may not have a chance to fully mature. If you are starting your onions indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Mammoth Lakes. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Mammoth Lakes is an average the actual date of last frost will vary from year to year. Since half of the time in Mammoth Lakes you get surprised by a frost after April 15 be ready to cover your onions if you have a surprise late frost.

USDA Zone Info for Mammoth Lakes

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 Mammoth Lakes

You may be interested in your other planting guides for Mammoth Lakes.