One of the best tools that you have as gardeners to help us figure out 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.

You should be able to figure out when you can plant sunflowers by reviewing the USDA zone info for Highland.

Planting Calendar for Sunflowers

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

It's probably a bad idea to plant sunflowers until after the last frost because they do not do well in cold weather.

The earliest that you can plant sunflowers in Highland 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. You probably don't want to wait any later than that or else 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

On average the last frost when the weather gets warmer is on February 15 in Highland. It might get as low as 25°F during the coldest months of winter.

Since the USDA zone info for Highland is just an average the actual date of last frost will vary from year to year. Half of the time in Highland there is a last frost after February 15 so just be sure to be ready to cover your sunflowers in the event of a late frost.

USDA Zone Info for Highland

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°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 30°F.

Plants to Grow in Highland

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