The USDA Zone info is a great tool for gardeners to help us estimate 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 determining when it's possible to plant welsh onion is to examine the USDA zone info for Mendota.

Planting Calendar for Welsh onion

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

Since welsh onion 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 welsh onion in Mendota 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 welsh onion and expect a good harvest is probably August. You probably don't want to wait any later than that or else your welsh onion may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your welsh onion indoors.

Last Frost Date

In Mendota 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.

Since the USDA zone info for Mendota is not always accurate the actual date of last frost will vary from year to year. Since half of the time in Mendota you get a frost after April 15 be ready to cover your welsh onion if you have a late frost.

USDA Zone Info for Mendota

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 Mendota

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