Before planting it is a good idea to find your USDA Zone info to figure out 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 Chelsea can be determined by reviewing 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 are barely cold tolerant which means that you can get them planted just a bit earlier than more sensitive plants.

The earliest that you can plant welsh onion in Chelsea 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 grow to maturity. You can get started a couple of weeks earlier by starting your welsh onion indoors.

Last Frost Date

On average the last frost has passed is on March 15 in Chelsea. In the coldest months of winter you should expect an average low temperature of 10°F.

Remember that USDA zone info for Chelsea is just an average and the actual date of last frost will vary from year to year. Half of the time in Chelsea you get surprised by a frost after March 15 so just be sure to be ready to cover your welsh onion if you have a surprise late frost.

USDA Zone Info for Chelsea

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°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 15°F.

Plants to Grow in Chelsea

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