When can I plant Sweet Williams in Zone 4b

One of the best tools that we have as gardeners to help us estimate our 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 our area.

In Zone 4b you can determine when it's the best time to plant sweet williams by looking at the USDA zone info.


Planting Calendar for Sweet Williams

Frost tolerance for sweet williams: Tolerant of some frost.
When you should plant them: Up to 5 weeks before last frost.

Since sweet williams do well in moderate cold you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant sweet williams
Possibly ok, but a risky time to plant sweet williams
Probably not a good time to plant sweet williams

The earliest that you can plant sweet williams 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 sweet williams and expect a good harvest is probably August. If you wait any later than that and your sweet williams may not have a chance to fully mature. If you are starting your sweet williams 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 May 15 in Zone 4b. In the coldest months of winter we should expect an average low temperature of -25°F.

Remember that our actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Zone 4b and it changes from year to year. Half of the time in Zone 4b last frost occurs after May 15 so always be ready to cover your sweet williams if we have a surprise late frost.

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 our other planting guides for Zone 4b.