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.

A way of determining when you can plant marigold is to use the USDA zone info for San Bernardino.

Planting Calendar for Marigold

Frost tolerance for marigold:	Not tolerant of frost.
When to plant:	After the last frost.

You can not plant marigold 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 marigold in San Bernardino 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 marigold and expect a good harvest is probably September. Any later than that and your marigold may not have a chance to fully mature. If you are starting your marigold 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 February 15 in San Bernardino. It might get as low as 25°F during the coldest months of winter.

Just be sure to remember that USDA zone info for San Bernardino is an average and the actual date of last frost is different every year. Half of the time in San Bernardino you get a frost after February 15 so make sure that you are ready to cover your marigold if you have a surprise late frost.

USDA Zone Info for San Bernardino

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 San Bernardino

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