One of the first steps you take when you are getting a good idea 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.

The USDA zone info for Sioux City should be used to estimate when it's a good idea to plant trifolium.

Planting Calendar for Trifolium

Frost tolerance for trifolium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since trifolium do ok in moderate cold you can plant them a bit earlier in the year than other plants that might not handle the cold.

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

The last month that you can plant trifolium and expect a good harvest is probably August. Any later than that and your trifolium may not have a chance to fully mature. Starting your trifolium indoors is a great way to get them started a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Sioux City. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Sioux City is just an average the actual date of last frost is different every year. Half of the time in Sioux City there is a last frost after April 15 so make sure that you are prepared to protect your trifolium if you have a 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.