One of the best tools that you have as gardeners to help us determine your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By referring to the USDA zone info for Grinnell it's possible to determine when it's a good idea to plant borage.

Planting Calendar for Borage

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

Borage can survive in a little bit of cold which means that you can plant them just a bit earlier in the year than other frost tender plants.

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

Last Frost Date

The average date of last frost is April 15 in Grinnell. You should expect an average low temperature of -20°F in the coldest months of winter.

Keep in mind that USDA zone info for Grinnell is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Grinnell you get surprised by a frost after April 15 be ready to cover your borage 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.