The USDA Zone info is a great tool for gardeners to help us figure out your gardening schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By using the USDA zone info for Hillsboro it's a good idea to estimate when it's possible to plant watercress.

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 mild cold which tells us that you can plant them just a tiny bit earlier in the year than plants that are more sensitive to the cold.

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

Last Frost Date

The average date of last frost is March 15 in Hillsboro. You can expect an average low temperature of 10°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 Hillsboro and it can change quite a bit from year to year. Since half of the time in Hillsboro you get surprised by a frost after March 15 be ready to cover your watercress if you have a surprise late frost.

USDA Zone Info for Hillsboro

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

This means that on a really cold year, the coldest it will get is 10°F. On most years you should be prepared to experience lows near 15°F.

Plants to Grow in Hillsboro

You may be interested in your other planting guides for Hillsboro.