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.

A common way of estimating when it's possible to plant alyssum is to refer to the USDA zone info for Renton.

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 earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant alyssum in Renton 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. Any later than that and your alyssum may not have a chance to really do well. If you are starting your alyssum indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost when the weather gets warmer is on March 15 in Renton. In the coldest months of winter you can expect an average low temperature of 15°F.

Always keep in mind that USDA zone info for Renton is just an average and the actual date of last frost changes from year to year. Half of the time in Renton you get a frost after March 15 so make sure that you are prepared to protect your alyssum in the event of a surprise late frost.

USDA Zone Info for Renton

Here is the info for USDA Zone 8b.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	15°F
Highest Expected Low	20°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 20°F.

Plants to Grow in Renton

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