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.

It's possible to estimate when it's a good idea to plant hosta by checking out the USDA zone info for Grinnell.

Planting Calendar for Hosta

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

You can plant hosta a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant hosta 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 hosta and expect a good harvest is probably September. If you wait any later than that and your hosta may not have a chance to fully mature. If you are starting your hosta indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Grinnell. In the coldest months of winter you can 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 is different every year. Half of the time in Grinnell last frost occurs after April 15 so make sure that you are prepared to cover your hosta in the event of one of those late frosts.

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.