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 alstromeria by referring to the USDA zone info for Sterling.

Planting Calendar for Alstromeria

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

Alstromeria do well in moderate cold which tells us that you can get them planted earlier than other plants that might not handle the cold.

The earliest that you can plant alstromeria in Sterling 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. Any later than that and your alstromeria may not have a chance to grow to maturity. If you are starting your alstromeria indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

The average date of last frost is April 15 in Sterling. In the coldest months of winter you can expect an average low temperature of -20°F.

Since the USDA zone info for Sterling is not always accurate the actual date of last frost is different every year. Half of the time in Sterling there is a last frost after April 15 so always be ready to protect your alstromeria if you have one of those late frosts.

USDA Zone Info for Sterling

Here is the info for USDA Zone 5a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-20°F
Highest Expected Low	-15°F

This means that on a really cold year, the coldest it will get is -20°F. On most years you should be prepared to experience lows near -15°F.

Plants to Grow in Sterling

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