The USDA Zone info is a great tool for gardeners to help us determine your gardening schedule. 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 the best time to plant alstromeria by referring to the USDA zone info for Zone 4b.

Planting Calendar for Alstromeria

Frost tolerance for alstromeria:	Tolerant of some frost.
When to plant:	Up to 5 weeks before last frost.

You can plant alstromeria a bit earlier in the year because they are moderately cold tolerant.

The earliest that you can plant alstromeria in Zone 4b 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 alstromeria and expect a good harvest is probably August. Any later than that and your alstromeria may not have a chance to fully mature. You can get started a few weeks earlier by starting your alstromeria indoors.

Last Frost Date

On average the last frost is on May 15 in Zone 4b. You should expect an average low temperature of -25°F in the coldest months of winter.

Remember that USDA zone info for Zone 4b is an average and the actual date of last frost changes from year to year. Since half of the time in Zone 4b you get surprised by a frost after May 15 be ready to protect your alstromeria in the event of one of those late frosts.

USDA Zone Info for Zone 4b

Here is the info for USDA Zone 4b.

Average Date of Last Frost (spring)	May 15
Average Date of First Frost (fall)	September 15
Lowest Expected Low	-25°F
Highest Expected Low	-20°F

This means that on a really cold year, the coldest it will get is -25°F. On most years you should be prepared to experience lows near -20°F.

Plants to Grow in Zone 4b

You may be interested in your other planting guides for Zone 4b.