One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when you can plant marigold is to use the USDA zone info for Keokuk.

Planting Calendar for Marigold

Frost tolerance for marigold:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Marigold require warm weather which tells us that it's important to wait until it warms up after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant marigold in Keokuk 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 really do well. If you are starting your marigold indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Keokuk the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -10°F.

Keep in mind that USDA zone info for Keokuk is an average and the actual date of last frost is different every year. Since half of the time in Keokuk last frost occurs after April 15 be ready to protect your marigold in the event of one of those late frosts.

USDA Zone Info for Keokuk

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 Keokuk

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