The USDA Zone info is a great tool for gardeners to help us estimate your gardening schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

One way of estimating when you can plant alyssum is to refer to the USDA zone info for Riverdale.

Planting Calendar for Alyssum

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

Since alyssum are one of those plants that can tolerate quite a bit of cold weather you can plant them earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant alyssum in Riverdale 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 few weeks earlier.

Last Frost Date

In Riverdale the average date of last frost happens on April 15. You can expect an average low temperature of -10°F in the coldest months of winter.

Since the USDA zone info for Riverdale is just an average the actual date of last frost is different every year. Half of the time in Riverdale it frosts late in the year after April 15 so just be sure to be ready to cover your alyssum if you have a late frost.

USDA Zone Info for Riverdale

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 Riverdale

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