Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Sioux City you can figure out when it's possible to plant flax by using the USDA zone info.

Planting Calendar for Flax

Frost tolerance for flax:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

Since flax are moderately cold tolerant you can plant them just a bit earlier in the year than more sensitive plants.

The earliest that you can plant flax in Sioux City is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant flax and expect a good harvest is probably September. Any later than that and your flax may not have a chance to grow to maturity. Starting your flax indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average the last frost is on April 15 in Sioux City. You can expect an average low temperature of -20°F in the coldest months of winter.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Sioux City and it can change quite a bit from year to year. Since half of the time in Sioux City you get a frost after April 15 be ready to protect your flax in the event of a surprise late frost.

USDA Zone Info for Sioux City

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Sioux City

You may be interested in your other planting guides for Sioux City.