The USDA Zone info is a great tool for gardeners to help us figure out 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.

A common way of determining when you can plant welsh onion is to check out the USDA zone info for Colusa.

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.

Welsh onion are barely cold tolerant which means that you can plant them slightly earlier than more sensitive plants.

The earliest that you can plant welsh onion in Colusa 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 welsh onion and expect a good harvest is probably September. If you wait any later than that and your welsh onion may not have a chance to really do well. Starting your welsh onion indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost is on February 15 in Colusa. It might get as low as 25°F during the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Colusa and it can change quite a bit from year to year. Since half of the time in Colusa it frosts late in the year after February 15 be ready to cover your welsh onion if you have a late frost.

USDA Zone Info for Colusa

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°F

This means that on a really cold year, the coldest it will get is 25°F. On most years you should be prepared to experience lows near 30°F.

Plants to Grow in Colusa

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