Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A way of making a decision about when it's a good idea to plant pyrethrum is to examine the USDA zone info for Johnston.

Planting Calendar for Pyrethrum

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

Pyrethrum do well in moderate cold which tells us that you can plant them a little bit earlier than other frost tender plants.

The earliest that you can plant pyrethrum in Johnston 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 grow to maturity. You can get started a couple of weeks earlier by starting your pyrethrum indoors.

Last Frost Date

In Johnston the average date of last frost happens on April 15. You can expect an average low temperature of -20°F in the coldest months of winter.

Remember that the actual date of last frost is just an average because it is based on the USDA zone info for Johnston and it will vary from year to year. Half of the time in Johnston it frosts late in the year after April 15 so always be ready to cover your pyrethrum if you have a surprise late frost.

USDA Zone Info for Johnston

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Johnston

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