One of the best tools that you have as gardeners to help us estimate 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 watercress in Carol Stream by looking at the USDA zone info.

Planting Calendar for Watercress

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

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

The earliest that you can plant watercress in Carol Stream 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 watercress and expect a good harvest is probably August. Any later than that and your watercress may not have a chance to grow to maturity. Starting your watercress indoors is a great way to get them started a few weeks earlier.

Last Frost Date

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

Just be sure to remember that the actual date of last frost may not be accurate from year to year because it is based on the USDA zone info for Carol Stream and it is different every year. Since half of the time in Carol Stream last frost occurs after April 15 be ready to cover your watercress if you have a surprise late frost.

USDA Zone Info for Carol Stream

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 Carol Stream

You may be interested in your other planting guides for Carol Stream.