The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You will be able to estimate when it's a good idea to plant tomatos by referring to the USDA zone info for Johnston.

Planting Calendar for Tomatos

Frost tolerance for tomatos:	Not tolerant of frost.
When to plant:	After the last frost.

It's not a good idea to plant tomatos until after the last frost has passed because they do not do well in cold weather.

The earliest that you can plant tomatos 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 tomatos and expect a good harvest is probably August. You probably don't want to wait any later than that or else your tomatos may not have a chance to grow to maturity. If you are starting your tomatos 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. In the coldest months of winter you should expect an average low temperature of -20°F.

Since the USDA zone info for Johnston may not be accurate from year to year the actual date of last frost will vary from year to year. Since half of the time in Johnston last frost occurs after April 15 be ready to protect your tomatos if you have one of those late frosts.

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.