One of the best tools that you have as gardeners to help us determine 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.

The USDA zone info for Zone 4a can be read to figure out when you can plant coleus.

Planting Calendar for Coleus

Frost tolerance for coleus:	Not tolerant of frost.
When to plant:	After the last frost when the weather gets warmer.

Since coleus are not cold tolerant you need to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant coleus in Zone 4a is May. However, you really should wait until June if you don't want to take any chances.

The last month that you can plant coleus and expect a good harvest is probably August. You probably don't want to wait any later than that or else your coleus may not have a chance to grow to maturity. If you are starting your coleus indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on May 15 in Zone 4a. You can expect an average low temperature of -30°F in the coldest months of winter.

Always keep in mind that USDA zone info for Zone 4a is just an average and the actual date of last frost can change quite a bit from year to year. Since half of the time in Zone 4a there is a last frost after May 15 be ready to cover your coleus if you have one of those late frosts.

USDA Zone Info for Zone 4a

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 Zone 4a

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