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.

One way of determining when it's the best time to plant broccoli is to examine the USDA zone info for Marshalltown.

Planting Calendar for Broccoli

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

Since broccoli are one of those plants that can tolerate a little bit of cold weather you can plant them just a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant broccoli in Marshalltown 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. If you wait any later than that and your broccoli may not have a chance to grow to maturity. Starting your broccoli indoors is a great way to get them started a few weeks earlier.

Last Frost Date

In Marshalltown the average date of last frost happens on April 15. You can expect an average low temperature of -20°F in the coldest months of winter.

Just be sure to remember that USDA zone info for Marshalltown is an average and the actual date of last frost changes from year to year. Half of the time in Marshalltown you get surprised by a frost after April 15 so make sure that you are prepared to protect your broccoli in the event of one of those late frosts.

USDA Zone Info for Marshalltown

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 Marshalltown

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