One of the first steps you take when you are estimating your gardening schedule is find your 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.

A common way of making a decision about when to plant delphinium is to refer to the USDA zone info for Melbourne.

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.

Delphinium do ok in moderate cold which tells us that you can start planting them slightly earlier than plants that are more sensitive to the cold.

The earliest that you can plant delphinium in Melbourne 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 Melbourne. In the coldest months of winter you can expect an average low temperature of 25°F.

Keep in mind that the actual date of last frost is just an average because it is based on the USDA zone info for Melbourne and it can change quite a bit from year to year. Since half of the time in Melbourne you get surprised by a frost after February 15 be ready to cover your delphinium if you have a surprise late frost.

USDA Zone Info for Melbourne

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 Melbourne

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