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.

By using the USDA zone info for Jefferson you should be able to determine when it's a good idea to plant sunflowers.

Planting Calendar for Sunflowers

Frost tolerance for sunflowers:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Sunflowers do not do well in cold weather which tells us that you really should wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant sunflowers in Jefferson is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant sunflowers and expect a good harvest is probably August. You probably don't want to wait any later than that or else your sunflowers may not have a chance to fully mature. If you are starting your sunflowers indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on March 15 in Jefferson. It might get as low as 10°F during the coldest months of winter.

Since the USDA zone info for Jefferson is just an average the actual date of last frost will vary from year to year. Half of the time in Jefferson last frost occurs after March 15 so make sure that you are prepared to protect your sunflowers if you have a late frost.

USDA Zone Info for Jefferson

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 Jefferson

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