Before planting it is a good idea to find your USDA Zone info to estimate your garden schedule. The most important data that the zone info tells us is average last frost and the lowest expected temperature for your area.

By referring to the USDA zone info for Windsor you will be able to determine when it's a good idea to plant delphinium.

Planting Calendar for Delphinium

Frost tolerance for delphinium:	Tolerant of a very small amount of frost.
When to plant:	Up to 3 weeks before last frost.

Since delphinium do ok in moderate cold you can plant them a bit earlier in the year than plants that are more sensitive to the cold.

The earliest that you can plant delphinium in Windsor 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 delphinium and expect a good harvest is probably September. You probably don't want to wait any later than that or else your delphinium may not have a chance to grow to maturity. You can get started a couple of weeks earlier by starting your delphinium indoors.

Last Frost Date

The average date of last frost is February 15 in Windsor. You can expect an average low temperature of 25°F in the coldest months of winter.

Remember that the actual date of last frost is an average because it is based on the USDA zone info for Windsor and it will vary from year to year. Since half of the time in Windsor you get a frost after February 15 be ready to protect your delphinium in the event of a late frost.

USDA Zone Info for Windsor

Here is the info for USDA Zone 9b.

Average Date of Last Frost (spring)	February 15
Average Date of First Frost (fall)	December 15
Lowest Expected Low	25°F
Highest Expected Low	30°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 30°F.

Plants to Grow in Windsor

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