One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

It's possible to figure out when it's the best time to plant tree onions by referring to 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 barely cold tolerant you can plant them slightly earlier in the year than more sensitive 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. Any later than that and your tree onions may not have a chance to fully mature. If you are starting your tree onions indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is March 15 in Lancaster. In the coldest months of winter you should expect an average low temperature of 10°F.

Since the USDA zone info for Lancaster may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Lancaster there is a last frost after March 15 so always be ready to cover your tree onions if you have one of those late frosts.

USDA Zone Info for Lancaster

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 Lancaster

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