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 should be able to figure out when it's a good idea to plant scallions by looking at the USDA zone info for Prospect Heights.

Planting Calendar for Scallions

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

Scallions tend to make it in a tiny bit of cold which means that you can plant them a bit earlier in the year than other frost tender plants.

The earliest that you can plant scallions in Prospect Heights 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 scallions and expect a good harvest is probably August. Any later than that and your scallions may not have a chance to fully mature. You can get started a few weeks earlier by starting your scallions indoors.

Last Frost Date

On average the last frost is on April 15 in Prospect Heights. You should expect an average low temperature of -15°F in the coldest months of winter.

Keep in mind that USDA zone info for Prospect Heights is an average and the actual date of last frost can change quite a bit from year to year. Half of the time in Prospect Heights you get surprised by a frost after April 15 so make sure that you are ready to protect your scallions if you have a late frost.

USDA Zone Info for Prospect Heights

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 Prospect Heights

You may be interested in your other planting guides for Prospect Heights.