One of the first steps you take when you are figuring out your gardening schedule is find your 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.

The USDA zone info for Zone 4a can be read to determine when it's a good idea to plant sorrel.

Planting Calendar for Sorrel

Frost tolerance for sorrel:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Sorrel are one of those plants that can tolerate a little bit of cold weather which tells us that you can plant them a little bit earlier than other plants that might not handle the cold.

The earliest that you can plant sorrel in Zone 4a 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 sorrel and expect a good harvest is probably August. If you wait any later than that and your sorrel may not have a chance to grow to maturity. If you are starting your sorrel 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 May 15 in Zone 4a. It might get as low as -30°F during the coldest months of winter.

Always keep in mind that USDA zone info for Zone 4a is just an average and the actual date of last frost is different every year. Half of the time in Zone 4a it frosts late in the year after May 15 so just be sure to be ready to cover your sorrel in the event of a surprise late frost.

USDA Zone Info for Zone 4a

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Zone 4a

You may be interested in your other planting guides for Zone 4a.