One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The earliest that you can plant sunflowers in Sulphur should be estimated by referring to the USDA zone info.

Planting Calendar for Sunflowers

Frost tolerance for sunflowers:	Not tolerant of frost.
When to plant:	After the last frost.

It's probably a bad idea to plant sunflowers until after the last frost because they are not cold tolerant.

The earliest that you can plant sunflowers in Sulphur 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 sunflowers and expect a good harvest is probably September. Any later than that and your sunflowers may not have a chance to fully mature. Starting your sunflowers indoors is a great way to get them started a little bit earlier.

Last Frost Date

In Sulphur the average date of last frost happens on February 15. It might get as low as 20°F during the coldest months of winter.

Remember that USDA zone info for Sulphur is an average and the actual date of last frost changes from year to year. Half of the time in Sulphur it frosts late in the year after February 15 so make sure that you are ready to protect your sunflowers in the event of a surprise late frost.

USDA Zone Info for Sulphur

Here is the info for USDA Zone 9a.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	20°F
Highest Expected Low	25°F

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

Plants to Grow in Sulphur

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