The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Sparta should be looked at to determine when it's a good idea to plant onions.

Planting Calendar for Onions

Frost tolerance for onions:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Onions do well in cold which tells us that you can plant them much earlier than other frost tender plants.

The earliest that you can plant onions in Sparta 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 onions and expect a good harvest is probably August. Any later than that and your onions may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your onions indoors.

Last Frost Date

On average the last frost is on May 15 in Sparta. It might get as low as -25°F during the coldest months of winter.

Keep in mind that USDA zone info for Sparta is just an average and the actual date of last frost changes from year to year. Since half of the time in Sparta you get surprised by a frost after May 15 be ready to cover your onions in the event of a surprise late frost.

USDA Zone Info for Sparta

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Sparta

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