One of the first steps you take when you are getting a good idea your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Colville can be reviewed to figure out when it's a good idea to plant welsh onion.

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 do ok in moderate cold you can plant them slightly earlier in the year than other plants that might not handle the cold.

The earliest that you can plant welsh onion in Colville 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. If you wait any later than that and your welsh onion may not have a chance to grow to maturity. If you are starting your welsh onion indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Colville the average date of last frost happens on April 15. You should expect an average low temperature of -10°F in the coldest months of winter.

It's important to remember that the actual date of last frost is an average because it is based on the USDA zone info for Colville and it is different every year. Since half of the time in Colville you get a frost after April 15 be ready to cover your welsh onion if you have a late frost.

USDA Zone Info for Colville

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 Colville

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