One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when it's a good idea to plant achillea is to check out the USDA zone info for Swarthmore.

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 pretty solid 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 Swarthmore 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. If you wait any later than that and your achillea may not have a chance to grow to maturity. Starting your achillea indoors is a great way to get them started a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Swarthmore. In the coldest months of winter you can expect an average low temperature of 0°F.

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 Swarthmore and it will vary from year to year. Since half of the time in Swarthmore you get surprised by a frost after April 15 be ready to protect your achillea if you have a surprise late frost.

USDA Zone Info for Swarthmore

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 Swarthmore

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