Before planting it is a good idea to find your USDA Zone info to estimate 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.

The first opportunity to plant welsh onion in Oswego should be figured out by referring to the USDA zone info.

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 do well in some cold which means that you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant welsh onion in Oswego 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 fully mature. Starting your welsh onion indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Oswego 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.

Since the USDA zone info for Oswego is not always accurate the actual date of last frost changes from year to year. Half of the time in Oswego last frost occurs after April 15 so make sure that you are prepared to cover your welsh onion if you have a surprise late frost.

USDA Zone Info for Oswego

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 Oswego

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