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.

In Caribou you can figure out when it's the best time to plant sweet sultan by referring to the USDA zone info.

Planting Calendar for Sweet Sultan

Frost tolerance for sweet sultan:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since sweet sultan are barely cold tolerant you can plant them a bit earlier in the year than more sensitive plants.

The earliest that you can plant sweet sultan in Caribou is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant sweet sultan and expect a good harvest is probably August. If you wait any later than that and your sweet sultan may not have a chance to grow to maturity. Starting your sweet sultan indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is May 15 in Caribou. You should expect an average low temperature of -30°F in the coldest months of winter.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Caribou and it is different every year. Half of the time in Caribou there is a last frost after May 15 so be sure to be ready to cover your sweet sultan in the event of a late frost.

USDA Zone Info for Caribou

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 Caribou

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