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.

The best time to plant cilantro in Johnston can be figured out by checking out the USDA zone info.

Planting Calendar for Cilantro

Frost tolerance for cilantro:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Cilantro are barely cold tolerant which means that you can get them planted just a bit earlier than other frost tender plants.

The earliest that you can plant cilantro in Johnston 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 cilantro and expect a good harvest is probably August. You probably don't want to wait any later than that or else your cilantro may not have a chance to fully mature. If you are starting your cilantro indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Johnston. You can expect an average low temperature of -20°F in the coldest months of winter.

Since the USDA zone info for Johnston may not be accurate from year to year the actual date of last frost can change quite a bit from year to year. Since half of the time in Johnston it frosts late in the year after April 15 be ready to cover your cilantro 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.