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.

It's possible to estimate when it's the best time to plant radicchio by using the USDA zone info for Zone 4b.

Planting Calendar for Radicchio

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

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

The earliest that you can plant radicchio 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 radicchio and expect a good harvest is probably August. If you wait any later than that and your radicchio may not have a chance to really do well. If you are starting your radicchio indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

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

Since the USDA zone info for Zone 4b is an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Zone 4b you get surprised by a frost after May 15 be ready to protect your radicchio in the event of 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.