The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The USDA zone info for Ottumwa can be reviewed to figure out when to plant nasturtium.

Planting Calendar for Nasturtium

Frost tolerance for nasturtium:	Not tolerant of frost.
When to plant:	After the last frost.

It's a bad idea to plant nasturtium until after all chance of frost has passed because they are not cold tolerant.

The earliest that you can plant nasturtium 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 nasturtium and expect a good harvest is probably August. You probably don't want to wait any later than that or else your nasturtium may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your nasturtium indoors.

Last Frost Date

On average the last frost is on April 15 in Ottumwa. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Ottumwa may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Ottumwa there is a last frost after April 15 be ready to protect your nasturtium 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.