The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Prosser you can figure out when to plant nigella by looking at the USDA zone info.

Planting Calendar for Nigella

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

Nigella do well in quite a bit of cold which tells us that you can plant them a lot earlier in the year than more sensitive plants.

The earliest that you can plant nigella 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 nigella and expect a good harvest is probably September. Any later than that and your nigella may not have a chance to grow to maturity. Starting your nigella indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Prosser. It might get as low as 0°F during the coldest months of winter.

Since the USDA zone info for Prosser is not always accurate the actual date of last frost will vary from year to year. Half of the time in Prosser you get a frost after April 15 so always be ready to cover your nigella 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.