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

It's a good idea to figure out when it's the best time to plant tree onions by looking at the USDA zone info for Lancaster.

Planting Calendar for Tree onions

Frost tolerance for tree onions:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since tree onions are one of those plants that can tolerate a tiny bit of cold weather you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant tree onions 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 tree onions and expect a good harvest is probably August. If you wait any later than that and your tree onions may not have a chance to fully mature. Starting your tree onions indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average the last frost has passed is on March 15 in Lancaster. You can expect an average low temperature of 15°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Lancaster may not be accurate from year to year and the actual date of last frost will vary from year to year. Since half of the time in Lancaster you get surprised by a frost after March 15 be ready to cover your tree onions if you have a late frost.

USDA Zone Info for Lancaster

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°F

This means that on a really cold year, the coldest it will get is 15°F. On most years you should be prepared to experience lows near 20°F.

Plants to Grow in Lancaster

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