One of the best tools that you have as gardeners to help us figure out your gardening schedule is the 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.

It's possible to determine when it's the best time to plant watercress by looking at the USDA zone info for Downers Grove.

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.

Watercress do ok in moderate cold which tells us that you can plant them slightly earlier than other plants that might not handle the cold.

The earliest that you can plant watercress in Downers Grove 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 fully mature. You can get started a little bit earlier by starting your watercress indoors.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Downers Grove. In the coldest months of winter you can expect an average low temperature of -15°F.

Keep in mind that USDA zone info for Downers Grove is not always accurate and the actual date of last frost will vary from year to year. Half of the time in Downers Grove there is a last frost after April 15 so make sure that you are ready to cover your watercress if you have one of those late frosts.

USDA Zone Info for Downers Grove

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 Downers Grove

You may be interested in your other planting guides for Downers Grove.