The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

The best time to plant marigold in Louisville should be figured out by reviewing the USDA zone info.

Planting Calendar for Marigold

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

It's probably a bad idea to plant marigold until after the last frost because they do not do well in cold weather.

The earliest that you can plant marigold in Louisville 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 marigold and expect a good harvest is probably August. Any later than that and your marigold may not have a chance to fully mature. You can get started a little bit earlier by starting your marigold indoors.

Last Frost Date

In Louisville the average date of last frost happens on April 15. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Louisville is an average the actual date of last frost is different every year. Since half of the time in Louisville last frost occurs after April 15 be ready to cover your marigold if you have a late frost.

USDA Zone Info for Louisville

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Louisville

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