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.

In Howell you can determine when you can plant polygonums by referring to the USDA zone info.

Planting Calendar for Polygonums

Frost tolerance for polygonums:	Not tolerant of frost.
When to plant:	After all chance of frost has passed.

Since polygonums are not cold tolerant you must wait until after the last frost when the weather gets warmer before you can plant them.

The earliest that you can plant polygonums in Howell is April. However, you really should wait until May if you don't want to take any chances.

The last month that you can plant polygonums and expect a good harvest is probably August. If you wait any later than that and your polygonums may not have a chance to really do well. Starting your polygonums indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Howell. You should expect an average low temperature of -10°F in the coldest months of winter.

Always keep in mind that USDA zone info for Howell is just an average and the actual date of last frost is different every year. Half of the time in Howell last frost occurs after April 15 so make sure that you are prepared to protect your polygonums if you have a surprise late frost.

USDA Zone Info for Howell

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Howell

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