Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of determining when to plant portulaca is to check out the USDA zone info for Johnston.

Planting Calendar for Portulaca

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

Since portulaca are not cold tolerant you need to wait until after the last frost before you can plant them.

The earliest that you can plant portulaca in Johnston 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 portulaca and expect a good harvest is probably August. If you wait any later than that and your portulaca may not have a chance to grow to maturity. You can get started a little bit earlier by starting your portulaca indoors.

Last Frost Date

In Johnston the average date of last frost happens on April 15. You should expect an average low temperature of -20°F in the coldest months of winter.

Always keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Johnston and it is different every year. Half of the time in Johnston last frost occurs after April 15 so just be sure to be ready to protect your portulaca if you have a surprise late frost.

USDA Zone Info for Johnston

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Johnston

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