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.

It's a good idea to estimate when it's a good idea to plant alternanthera by using the USDA zone info for Keene.

Planting Calendar for Alternanthera

Frost tolerance for alternanthera:	Not tolerant of frost.
When to plant:	After the last frost has passed.

It's probably a bad idea to plant alternanthera until after the last frost when the weather gets warmer because they do not do well in cold weather.

The earliest that you can plant alternanthera in Keene 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 alternanthera and expect a good harvest is probably August. You probably don't want to wait any later than that or else your alternanthera may not have a chance to grow to maturity. You can get started a few weeks earlier by starting your alternanthera indoors.

Last Frost Date

On average the last frost is on April 15 in Keene. You can expect an average low temperature of -15°F in the coldest months of winter.

It's important to remember 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 Keene and it will vary from year to year. Since half of the time in Keene you get a frost after April 15 be ready to cover your alternanthera in the event of a late frost.

USDA Zone Info for Keene

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Keene

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