When can I plant Sunflowers in Zone 9b

One of the best tools that we have as gardeners to help us estimate our 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 our area.

The best time to plant sunflowers in Zone 9b should be figured out by referring to the USDA zone info.


Planting Calendar for Sunflowers

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

It's probably a bad idea to plant sunflowers until after the last frost because they require warm weather.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant sunflowers
Possibly ok, but a risky time to plant sunflowers
Probably not a good time to plant sunflowers

The earliest that you can plant sunflowers in Zone 9b 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 grow to maturity. If you are starting your sunflowers indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is February 15 in Zone 9b. In the coldest months of winter we should expect an average low temperature of 25°F.

Always keep in mind that USDA zone info for Zone 9b may not be accurate from year to year and our actual date of last frost is different every year. Half of the time in Zone 9b last frost occurs after February 15 so always be ready to cover your sunflowers in the event of a surprise late frost.

USDA Zone Info for Zone 9b

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 Low25°F
Highest Expected Low30°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 Zone 9b

You may be interested in our other planting guides for Zone 9b.