One of the first steps you take when you are making a decision about your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

In Riverdale you can estimate when to plant trailing portulaca by referring to the USDA zone info.

Planting Calendar for Trailing Portulaca

Frost tolerance for trailing portulaca:	Not tolerant of frost.
When to plant:	After the last frost has passed.

Trailing Portulaca are not cold tolerant which tells us that it is important to wait until it warms up after all chance of frost has passed before you can plant them.

The earliest that you can plant trailing portulaca in Riverdale is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant trailing portulaca and expect a good harvest is probably August. If you wait any later than that and your trailing portulaca may not have a chance to grow to maturity. Starting your trailing portulaca indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Riverdale the average date of last frost happens on April 15. You should expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Riverdale is just an average the actual date of last frost can change quite a bit from year to year. Since half of the time in Riverdale last frost occurs after April 15 be ready to protect your trailing portulaca in the event of a late frost.

USDA Zone Info for Riverdale

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°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 -5°F.

Plants to Grow in Riverdale

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