Before planting it is a good idea to find your USDA Zone info to estimate 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.

One way of making a decision about when to plant tritoma is to refer to the USDA zone info for Grinnell.

Planting Calendar for Tritoma

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

Tritoma are one of those plants that can tolerate quite a bit of cold weather which means that you can start planting them much earlier than plants that are more sensitive to the cold.

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

Last Frost Date

On average all chance of frost has passed is on April 15 in Grinnell. In the coldest months of winter you should expect an average low temperature of -20°F.

Since the USDA zone info for Grinnell is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Grinnell you get a frost after April 15 so just be sure to be ready to protect your tritoma if you have a late frost.

USDA Zone Info for Grinnell

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 Grinnell

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