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

A common way of figuring out when you can plant shallots is to check out the USDA zone info for Boulder.

Planting Calendar for Shallots

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

Since shallots are one of those plants that can tolerate a tiny bit of cold weather you can plant them just a tiny bit earlier in the year than more sensitive plants.

The earliest that you can plant shallots in Boulder 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 shallots and expect a good harvest is probably August. You probably don't want to wait any later than that or else your shallots may not have a chance to really do well. If you are starting your shallots indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

In Boulder the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -15°F.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Boulder and it changes from year to year. Half of the time in Boulder it frosts late in the year after April 15 so make sure that you are prepared to cover your shallots in the event of a late frost.

USDA Zone Info for Boulder

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-15°F
Highest Expected Low	-10°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 -10°F.

Plants to Grow in Boulder

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