One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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 way of getting a good idea when it's possible to plant black radish is to look at the USDA zone info for Havre.

Planting Calendar for Black radish

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

Since black radish do well in moderate cold you can plant them a little earlier in the year than more sensitive plants.

The earliest that you can plant black radish in Havre 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 black radish and expect a good harvest is probably August. Any later than that and your black radish may not have a chance to really do well. Starting your black radish indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Havre. In the coldest months of winter you can expect an average low temperature of -30°F.

It's important to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Havre and it is different every year. Half of the time in Havre you get surprised by a frost after May 15 so just be sure to be ready to protect your black radish in the event of a late frost.

USDA Zone Info for Havre

Here is the info for USDA Zone 4a.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-30°F
Highest Expected Low	-25°F

This means that on a really cold year, the coldest it will get is -30°F. On most years you should be prepared to experience lows near -25°F.

Plants to Grow in Havre

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