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.

A way of estimating when to plant yarrow is to look at the USDA zone info for Piqua.

Planting Calendar for Yarrow

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

Yarrow do ok in pretty solid cold which means that you can plant them quite a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant yarrow in Piqua 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. If you wait any later than that and your yarrow may not have a chance to grow to maturity. Starting your yarrow 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 Piqua. You should expect an average low temperature of -10°F in the coldest months of winter.

Keep in mind that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Piqua and it can change quite a bit from year to year. Since half of the time in Piqua you get surprised by a frost after April 15 be ready to cover your yarrow if you have a surprise late frost.

USDA Zone Info for Piqua

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Piqua

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