Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By checking out the USDA zone info for Grinnell it's a good idea to estimate when it's a good idea to plant lupine.

Planting Calendar for Lupine

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

Since lupine are one of those plants that can tolerate a little bit of cold weather you can plant them a little earlier in the year than other plants that might not handle the cold.

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

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.

It's important 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 Grinnell and it will vary from year to year. Since half of the time in Grinnell you get a frost after April 15 be ready to protect your lupine in the event of a surprise 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.