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.

The USDA zone info for Alton can be read to determine when it's a good idea 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.

Bishop's Weed are one of those plants that can tolerate quite a bit of cold weather which tells us that you can plant them much earlier than plants that are more sensitive to the cold.

The earliest that you can plant bishop's weed in Alton 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 few weeks earlier.

Last Frost Date

On average the last frost is on April 15 in Alton. It might get as low as -10°F during the coldest months of winter.

Keep in mind that USDA zone info for Alton may not be accurate from year to year and the actual date of last frost changes from year to year. Half of the time in Alton it frosts late in the year after April 15 so just be sure to be ready to cover your bishop's weed if you have one of those late frosts.

USDA Zone Info for Alton

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 Alton

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