Before planting it is a good idea to find your USDA Zone info to figure out your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By reviewing the USDA zone info for Casper you should be able to figure out when it's the best time to plant alstromeria.

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 just a bit earlier in the year because they are one of those plants that can tolerate a little bit of cold weather.

The earliest that you can plant alstromeria in Casper 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 really do well. 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

In Casper the average date of last frost happens on April 15. In the coldest months of winter you should expect an average low temperature of -20°F.

Always keep in mind that the actual date of last frost is an average because it is based on the USDA zone info for Casper and it changes from year to year. Half of the time in Casper there is a last frost after April 15 so just be sure to be ready to cover your alstromeria in the event of a surprise late frost.

USDA Zone Info for Casper

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 Casper

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