Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Prosser can be reviewed to determine when you can plant larkspur.

Planting Calendar for Larkspur

Frost tolerance for larkspur:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Larkspur are one of those plants that can tolerate quite a bit of cold weather which means that you can plant them a quite a bit earlier than other plants that might not handle the cold.

The earliest that you can plant larkspur in Prosser 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 larkspur and expect a good harvest is probably September. Any later than that and your larkspur may not have a chance to really do well. Starting your larkspur indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Prosser the average date of last frost happens on April 15. It might get as low as 0°F during the coldest months of winter.

Since the USDA zone info for Prosser is just an average the actual date of last frost will vary from year to year. Half of the time in Prosser you get surprised by a frost after April 15 so be sure to be ready to protect your larkspur in the event of a late frost.

USDA Zone Info for Prosser

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Prosser

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