One of the first steps you take when you are determining your gardening schedule is find your 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 reviewing the USDA zone info for Napa it's possible to estimate when it's a good idea to plant marigold.

Planting Calendar for Marigold

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

Since marigold are not cold tolerant you need to wait until after the last frost has passed before you can plant them.

The earliest that you can plant marigold in Napa 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 really do well. You can get started a couple of weeks earlier by starting your marigold indoors.

Last Frost Date

The average date of last frost is February 15 in Napa. You should expect an average low temperature of 25°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is not always accurate because it is based on the USDA zone info for Napa and it is different every year. Since half of the time in Napa it frosts late in the year after February 15 be ready to protect your marigold in the event of a surprise late frost.

USDA Zone Info for Napa

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 Napa

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