The USDA Zone info is a great tool for gardeners to help us determine your gardening 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 estimating when it's the best time to plant cauliflower is to examine the USDA zone info for Grinnell.

Planting Calendar for Cauliflower

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

Cauliflower can survive in a little bit of cold which tells us that you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant cauliflower 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 cauliflower and expect a good harvest is probably September. Any later than that and your cauliflower may not have a chance to really do well. Starting your cauliflower indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Grinnell. You should expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Grinnell is an average the actual date of last frost will vary from year to year. Half of the time in Grinnell last frost occurs after April 15 so be sure to be ready to protect your cauliflower 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.