One of the best tools that you have as gardeners to help us estimate your gardening schedule is the USDA zone info. 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 Olney should be reviewed to figure out when it's possible to plant achillea.

Planting Calendar for Achillea

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

Achillea do ok in quite a bit of cold which means that you can plant them much earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant achillea in Olney 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 achillea and expect a good harvest is probably September. Any later than that and your achillea may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your achillea indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Olney. In the coldest months of winter you can expect an average low temperature of -10°F.

Since the USDA zone info for Olney is not always accurate the actual date of last frost can change quite a bit from year to year. Since half of the time in Olney you get surprised by a frost after April 15 be ready to cover your achillea in the event of one of those late frosts.

USDA Zone Info for Olney

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 Olney

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