One of the first steps you take when you are determining your gardening schedule is find your 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.

By referring to the USDA zone info for Ottumwa it's possible to estimate when it's the best time to plant calla lily.

Planting Calendar for Calla Lily

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

It's not a good idea to plant calla lily until after the last frost because they are not cold tolerant.

The earliest that you can plant calla lily 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 calla lily and expect a good harvest is probably August. You probably don't want to wait any later than that or else your calla lily may not have a chance to really do well. You can get started a little bit earlier by starting your calla lily indoors.

Last Frost Date

On average all chance of frost has passed is on April 15 in Ottumwa. It might get as low as -15°F during the coldest months of winter.

Remember that USDA zone info for Ottumwa is an average and the actual date of last frost will vary from year to year. Half of the time in Ottumwa there is a last frost after April 15 so make sure that you are ready to protect your calla lily in the event of a 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.