When to Plant Radishes in Johnstown, CO

One of the best tools that you have as gardeners to help us estimate 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.

The USDA zone info for Johnstown can be reviewed to determine when it's possible to plant radishes.


Planting Calendar for Radishes

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

You can plant radishes quite a bit earlier in the year because they are very cold tolerant.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant radishes
Possibly ok, but a risky time to plant radishes
Probably not a good time to plant radishes

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

Last Frost Date

On average the last frost is on April 15 in Johnstown. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Johnstown may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Johnstown you get surprised by a frost after April 15 so be sure to be ready to protect your radishes in the event of one of those late frosts.

USDA Zone Info for Johnstown

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Johnstown

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