One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In San Marino you can figure out when it's a good idea to plant sunflowers by looking at 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 do not do well in cold weather.

The earliest that you can plant sunflowers in San Marino is February. However, you really should wait until March 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 few weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on January 31 in San Marino. In the coldest months of winter you should expect an average low temperature of 30°F.

Since the USDA zone info for San Marino may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in San Marino you get a frost after January 31 be ready to protect your sunflowers if you have a late frost.

USDA Zone Info for San Marino

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in San Marino

You may be interested in your other planting guides for San Marino.