One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of making a decision about when it's the best time to plant pyrethrum is to use the USDA zone info for Lancaster.

Planting Calendar for Pyrethrum

Frost tolerance for pyrethrum:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since pyrethrum are moderately cold tolerant you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant pyrethrum in Lancaster 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 pyrethrum and expect a good harvest is probably September. Any later than that and your pyrethrum may not have a chance to really do well. You can get started a few weeks earlier by starting your pyrethrum indoors.

Last Frost Date

The average date of last frost is April 15 in Lancaster. You should expect an average low temperature of -5°F in the coldest months of winter.

Just be sure to remember 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 Lancaster and it will vary from year to year. Half of the time in Lancaster it frosts late in the year after April 15 so make sure that you are ready to cover your pyrethrum in the event of a surprise late frost.

USDA Zone Info for Lancaster

Here is the info for USDA Zone 6b.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-5°F
Highest Expected Low	0°F

This means that on a really cold year, the coldest it will get is -5°F. On most years you should be prepared to experience lows near 0°F.

Plants to Grow in Lancaster

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