One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Zone 4b you will be able to figure out when it's possible to plant broccoli.

Planting Calendar for Broccoli

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

You can plant broccoli just a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant broccoli in Zone 4b is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant broccoli and expect a good harvest is probably August. You probably don't want to wait any later than that or else your broccoli may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your broccoli indoors.

Last Frost Date

The average date of last frost is May 15 in Zone 4b. You can expect an average low temperature of -25°F in the coldest months of winter.

Since the USDA zone info for Zone 4b may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Zone 4b there is a last frost after May 15 be ready to protect your broccoli if you have one of those late frosts.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.