Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

By using the USDA zone info for Marshalltown you will be able to figure out when it's the best time to plant lemon balm.

Planting Calendar for Lemon balm

Frost tolerance for lemon balm:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since lemon balm do ok in moderate cold you can plant them slightly earlier in the year than other frost tender plants.

The earliest that you can plant lemon balm in Marshalltown is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant lemon balm and expect a good harvest is probably August. If you wait any later than that and your lemon balm may not have a chance to really do well. If you are starting your lemon balm indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Marshalltown. You should expect an average low temperature of -20°F in the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Marshalltown and it is different every year. Since half of the time in Marshalltown it frosts late in the year after April 15 be ready to protect your lemon balm 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.