Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. 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 Derby should be reffered to in order to estimate 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.

Welsh onion are one of those plants that can tolerate a tiny bit of cold weather which means that you can plant them slightly earlier than more sensitive plants.

The earliest that you can plant welsh onion in Derby 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 really do well. You can get started a little bit earlier by starting your welsh onion indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Derby. In the coldest months of winter you can expect an average low temperature of -5°F.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Derby and it will vary from year to year. Half of the time in Derby you get surprised by a frost after April 15 so always be ready to cover your welsh onion if you have a late frost.

USDA Zone Info for Derby

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 Derby

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