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 referring to the USDA zone info for Napa it's possible to determine when it's a good idea to plant tropical water plants.

Planting Calendar for Tropical Water Plants

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

Tropical Water Plants require warm weather which means that you really should wait until it warms up after the last frost before you can plant them.

The earliest that you can plant tropical water plants 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 tropical water plants and expect a good harvest is probably September. You probably don't want to wait any later than that or else your tropical water plants may not have a chance to really do well. Starting your tropical water plants indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average all chance of frost has passed is on February 15 in Napa. You can expect an average low temperature of 25°F in the coldest months of winter.

Since the USDA zone info for Napa is just an average the actual date of last frost is different every year. Since half of the time in Napa there is a last frost after February 15 be ready to cover your tropical water plants if you have a 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.