One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

It's possible to determine when it's the best time to plant tree onions by checking out the USDA zone info for Greenbelt.

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 just a tiny bit earlier in the year than other frost tender plants.

The earliest that you can plant tree onions in Greenbelt 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 grow to maturity. If you are starting your tree onions indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Greenbelt. In the coldest months of winter you can expect an average low temperature of 0°F.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Greenbelt and it can change quite a bit from year to year. Half of the time in Greenbelt last frost occurs after April 15 so be sure to be ready to protect your tree onions if you have a late frost.

USDA Zone Info for Greenbelt

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Greenbelt

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