One of the first steps you take when you are determining your gardening schedule is find your USDA Zone info. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

You can determine when it's a good idea to plant alstromeria in Watertown by using the USDA zone info.

Planting Calendar for Alstromeria

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

Alstromeria tend to make it in mild cold which tells us that 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 Watertown 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. You probably don't want to wait any later than that or else 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 Watertown the average date of last frost happens on May 15. It might get as low as -25°F during the coldest months of winter.

Since the USDA zone info for Watertown is just an average the actual date of last frost can change quite a bit from year to year. Half of the time in Watertown you get surprised by a frost after May 15 so be sure to be ready to cover your alstromeria in the event of one of those late frosts.

USDA Zone Info for Watertown

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 Watertown

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