One of the first steps you take when you are getting a good idea 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.

By checking out the USDA zone info for Des Moines you should be able to determine when it's a good idea to plant alyssum.

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 very cold tolerant you can plant them much earlier in the year than more sensitive plants.

The earliest that you can plant alyssum in Des Moines 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. You probably don't want to wait any later than that or else your alyssum may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your alyssum indoors.

Last Frost Date

In Des Moines the average date of last frost happens on April 15. It might get as low as -15°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is an average because it is based on the USDA zone info for Des Moines and it is different every year. Since half of the time in Des Moines you get a frost after April 15 be ready to cover your alyssum if you have one of those late frosts.

USDA Zone Info for Des Moines

Here is the info for USDA Zone 5b.

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

This means that on a really cold year, the coldest it will get is -15°F. On most years you should be prepared to experience lows near -10°F.

Plants to Grow in Des Moines

You may be interested in your other planting guides for Des Moines.