One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can estimate when it's a good idea to plant tree onions in Sioux Center by checking out the USDA zone info.

Planting Calendar for Tree onions

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

Since tree onions do ok in moderate cold you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant tree onions in Sioux Center 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 tree onions and expect a good harvest is probably August. If you wait any later than that and your tree onions may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your tree onions indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Sioux Center. It might get as low as -20°F during the coldest months of winter.

Since the USDA zone info for Sioux Center may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Half of the time in Sioux Center last frost occurs after April 15 so make sure that you are prepared to cover your tree onions in the event of one of those late frosts.

USDA Zone Info for Sioux Center

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 Center

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