Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

You can estimate when it's possible to plant sunflowers in Redwood City by reviewing 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 not a good idea to plant sunflowers until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant sunflowers in Redwood City 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. 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 Redwood City the average date of last frost happens on February 15. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Redwood City may not be accurate from year to year the actual date of last frost is different every year. Half of the time in Redwood City there is a last frost after February 15 so always be ready to cover your sunflowers in the event of a surprise late frost.

USDA Zone Info for Redwood City

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 Redwood City

You may be interested in your other planting guides for Redwood City.