The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You will be able to figure out when it's possible to plant pearl onions by using the USDA zone info for Herndon.

Planting Calendar for Pearl onions

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

Since pearl onions 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 pearl onions in Herndon 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 pearl onions and expect a good harvest is probably August. If you wait any later than that and your pearl onions may not have a chance to really do well. You can get started a little bit earlier by starting your pearl onions indoors.

Last Frost Date

The average date of last frost is April 15 in Herndon. It might get as low as 0°F during the coldest months of winter.

Keep in mind that USDA zone info for Herndon is just an average and the actual date of last frost is different every year. Since half of the time in Herndon you get surprised by a frost after April 15 be ready to protect your pearl onions if you have a surprise late frost.

USDA Zone Info for Herndon

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 Herndon

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