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.

The USDA zone info for Tiffin should be reviewed to determine when it's the best time to plant bishop's weed.

Planting Calendar for Bishop's Weed

Frost tolerance for bishop's weed:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since bishop's weed are one of those plants that can tolerate quite a bit of cold weather you can plant them quite a bit earlier in the year than more sensitive plants.

The earliest that you can plant bishop's weed in Tiffin 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 bishop's weed and expect a good harvest is probably September. Any later than that and your bishop's weed may not have a chance to fully mature. Starting your bishop's weed indoors is a great way to get them started a couple of weeks earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on April 15 in Tiffin. In the coldest months of winter you should expect an average low temperature of -10°F.

Keep in mind 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 Tiffin and it will vary from year to year. Since half of the time in Tiffin there is a last frost after April 15 be ready to cover your bishop's weed in the event of a late frost.

USDA Zone Info for Tiffin

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 Tiffin

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