One of the best tools that you have as gardeners to help us figure out your gardening schedule is the USDA zone info. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

A common way of making a decision about when it's a good idea to plant alstromeria is to use the USDA zone info for Manhattan.

Planting Calendar for Alstromeria

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

Since alstromeria are moderately cold tolerant you can plant them a bit earlier in the year than other plants that might not handle the cold.

The earliest that you can plant alstromeria in Manhattan 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 alstromeria and expect a good harvest is probably September. If you wait any later than that and your alstromeria may not have a chance to fully mature. Starting your alstromeria 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 Manhattan. It might get as low as -15°F during the coldest months of winter.

Since the USDA zone info for Manhattan may not be accurate from year to year the actual date of last frost will vary from year to year. Half of the time in Manhattan it frosts late in the year after April 15 so make sure that you are prepared to protect your alstromeria in the event of a late frost.

USDA Zone Info for Manhattan

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 Manhattan

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