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

The earliest that you can plant yarrow in Prosser can be estimated by referring to the USDA zone info.

Planting Calendar for Yarrow

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

Yarrow are very cold tolerant which tells us that you can plant them a quite a bit earlier than more sensitive plants.

The earliest that you can plant yarrow 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 yarrow and expect a good harvest is probably September. You probably don't want to wait any later than that or else your yarrow may not have a chance to really do well. Starting your yarrow 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. You should expect an average low temperature of 0°F in the coldest months of winter.

Remember that USDA zone info for Prosser is an average and the actual date of last frost is different every year. Since half of the time in Prosser last frost occurs after April 15 be ready to cover your yarrow if you have one of those late frosts.

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.