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.

By checking out the USDA zone info for Campbell you will be able to estimate when to plant sunflowers.

Planting Calendar for Sunflowers

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

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

The earliest that you can plant sunflowers in Campbell 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. If you wait any later than that and 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 few weeks earlier.

Last Frost Date

In Campbell the average date of last frost happens on February 15. In the coldest months of winter you can expect an average low temperature of 25°F.

Remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Campbell and it changes from year to year. Half of the time in Campbell you get a frost after February 15 so just be sure to be ready to cover your sunflowers in the event of one of those late frosts.

USDA Zone Info for Campbell

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 Campbell

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