Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

In Ottumwa you can figure out when to plant argyranthemum by referring to the USDA zone info.

Planting Calendar for Argyranthemum

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

Since argyranthemum do not do well in cold weather it's necessary to wait until after all chance of frost has passed before you can plant them.

The earliest that you can plant argyranthemum in Ottumwa 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 argyranthemum and expect a good harvest is probably August. You probably don't want to wait any later than that or else your argyranthemum may not have a chance to fully mature. If you are starting your argyranthemum indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Ottumwa. You can expect an average low temperature of -15°F in the coldest months of winter.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Ottumwa and it is different every year. Half of the time in Ottumwa last frost occurs after April 15 so always be ready to protect your argyranthemum if you have a surprise late frost.

USDA Zone Info for Ottumwa

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Ottumwa

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