One of the first steps you take when you are making a decision about 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.

A common way of determining when to plant broccoli is to use the USDA zone info for Janesville.

Planting Calendar for Broccoli

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

Broccoli are moderately cold tolerant which means that you can plant them earlier than plants that are more sensitive to the cold.

The earliest that you can plant broccoli in Janesville 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 broccoli and expect a good harvest is probably September. Any later than that and your broccoli may not have a chance to really do well. If you are starting your broccoli indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

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

Just be sure to remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Janesville and it will vary from year to year. Half of the time in Janesville last frost occurs after April 15 so always be ready to cover your broccoli if you have a surprise late frost.

USDA Zone Info for Janesville

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 Janesville

You may be interested in your other planting guides for Janesville.