When to Plant Broccoli in Johnston, IA

The USDA Zone info is a great tool for gardeners to help us determine 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.

By reviewing the USDA zone info for Johnston you should be able to figure out when you can plant broccoli.

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Planting Calendar for Broccoli

Frost tolerance for broccoli: Tolerant of some frost.
When to plant: Up to 5 weeks before last frost.

Since broccoli do well in moderate cold you can plant them a little bit earlier in the year than plants that are more sensitive to the cold.

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

The earliest that you can plant broccoli 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 broccoli and expect a good harvest is probably September. You probably don't want to wait any later than that or else your broccoli may not have a chance to grow to maturity. Starting your broccoli indoors is a great way to get them started a little bit earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Johnston. In the coldest months of winter you can expect an average low temperature of -20°F.

It's important to remember that the actual date of last frost may not be accurate from year to year 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 always be ready to cover your broccoli 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.