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.

In Chester you can determine when it's a good idea to plant welsh onion by looking at 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 ok in moderate cold which means that you can start planting them slightly earlier than other frost tender plants.

The earliest that you can plant welsh onion in Chester 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. Any later than that and your welsh onion may not have a chance to fully mature. If you are starting your welsh onion indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Chester. You can expect an average low temperature of -5°F in the coldest months of winter.

Since the USDA zone info for Chester is just an average the actual date of last frost will vary from year to year. Half of the time in Chester you get surprised by a frost after April 15 so make sure that you are prepared to protect your welsh onion in the event of a surprise late frost.

USDA Zone Info for Chester

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Chester

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