One of the first steps you take when you are estimating your gardening schedule is find your USDA Zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By checking out the USDA zone info for Grinnell it's possible to estimate when to plant bok choi.

Planting Calendar for Bok Choi

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

You can plant bok choi a little bit earlier in the year because they do well in moderate cold.

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

Last Frost Date

The average date of last frost is 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 may not be accurate from year to year the actual date of last frost is different every year. Since half of the time in Grinnell you get surprised by a frost after April 15 be ready to protect your bok choi if you have 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.