One of the first steps you take when you are getting a good idea your gardening schedule is find your 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.

By using the USDA zone info for Ambler it's a good idea to estimate when it's a good idea 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.

You can plant watercress a bit earlier in the year because they are barely cold tolerant.

The earliest that you can plant watercress in Ambler 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. If you wait any later than that and your watercress may not have a chance to really do well. Starting your watercress indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Ambler. You can expect an average low temperature of 0°F in the coldest months of winter.

Since the USDA zone info for Ambler is an average the actual date of last frost is different every year. Since half of the time in Ambler it frosts late in the year after April 15 be ready to cover your watercress in the event of a late frost.

USDA Zone Info for Ambler

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	0°F
Highest Expected Low	5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Ambler

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