One of the first steps you take when you are figuring out your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By reviewing the USDA zone info for Williston you should be able to figure out 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 the last frost has passed.

Since sunflowers require warm weather you have to wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant sunflowers in Williston is May. However, you really should wait until June 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 grow to maturity. Starting your sunflowers indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

In Williston the average date of last frost happens on May 15. In the coldest months of winter you can expect an average low temperature of -30°F.

Keep in mind that USDA zone info for Williston may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Williston last frost occurs after May 15 so make sure that you are ready to cover your sunflowers in the event of a late frost.

USDA Zone Info for Williston

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 Williston

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