Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Lancaster you can figure out when you can plant welsh onion 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.

Since welsh onion do ok in moderate cold you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant welsh onion in Lancaster 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. 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

On average the last frost has passed is on April 15 in Lancaster. In the coldest months of winter you can expect an average low temperature of -10°F.

Since the USDA zone info for Lancaster is an average the actual date of last frost can change quite a bit from year to year. Half of the time in Lancaster you get a frost after April 15 so make sure that you are ready to protect your welsh onion in the event of a late frost.

USDA Zone Info for Lancaster

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 Lancaster

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