One of the best tools that you have as gardeners to help us determine 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.

You should be able to estimate when it's the best time to plant alyssum by checking out the USDA zone info for Waterloo.

Planting Calendar for Alyssum

Frost tolerance for alyssum:	Very tolerant of frost.
When to plant:	Up to 7 weeks before last frost.

Since alyssum do well in cold you can plant them a lot earlier in the year than other frost tender plants.

The earliest that you can plant alyssum in Waterloo 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 alyssum and expect a good harvest is probably September. If you wait any later than that and your alyssum may not have a chance to grow to maturity. If you are starting your alyssum 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 Waterloo. It might get as low as -10°F during the coldest months of winter.

Keep in mind that USDA zone info for Waterloo is just an average and the actual date of last frost will vary from year to year. Half of the time in Waterloo you get surprised by a frost after April 15 so just be sure to be ready to protect your alyssum if you have one of those late frosts.

USDA Zone Info for Waterloo

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)	April 15
Average Date of First Frost (fall)	October 15
Lowest Expected Low	-10°F
Highest Expected Low	-5°F

This means that on a really cold year, the coldest it will get is -10°F. On most years you should be prepared to experience lows near -5°F.

Plants to Grow in Waterloo

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