One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

A way of figuring out when to plant asparagus is to look at the USDA zone info for Johnston.

Planting Calendar for Asparagus

Frost tolerance for asparagus:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Asparagus are very cold tolerant which tells us that you can plant them a quite a bit earlier than other frost tender plants.

The earliest that you can plant asparagus in Johnston is February. However, you really should wait until March if you don't want to take any chances.

The last month that you can plant asparagus and expect a good harvest is probably September. You probably don't want to wait any later than that or else your asparagus may not have a chance to fully mature. You can get started a couple of weeks earlier by starting your asparagus indoors.

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.

It's important to remember 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. Since half of the time in Johnston you get surprised by a frost after April 15 be ready to protect your asparagus if you have a 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.