Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

One way of estimating when it's the best time to plant welsh onion is to look at the USDA zone info for Stillwater.

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 one of those plants that can tolerate a tiny bit of cold weather which tells us that you can start planting them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant welsh onion in Stillwater is April. However, you really should wait until May 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. Any later than that and your welsh onion may not have a chance to really do well. If you are starting your welsh onion indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is May 15 in Stillwater. You should expect an average low temperature of -25°F in the coldest months of winter.

It's important to remember that USDA zone info for Stillwater is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Stillwater it frosts late in the year after May 15 be ready to cover your welsh onion in the event of a late frost.

USDA Zone Info for Stillwater

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°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 -20°F.

Plants to Grow in Stillwater

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