Before planting it is a good idea to find your USDA Zone info to determine 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.

The first chance to plant leeks in Diamond Bar should be estimated by using the USDA zone info.

Planting Calendar for Leeks

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

Leeks are very cold tolerant which tells us that you can get them planted much earlier than other frost tender plants.

The earliest that you can plant leeks in Diamond Bar is January. However, you really should wait until February if you don't want to take any chances.

The last month that you can plant leeks and expect a good harvest is probably October. If you wait any later than that and your leeks may not have a chance to fully mature. You can get started a few weeks earlier by starting your leeks indoors.

Last Frost Date

In Diamond Bar the average date of last frost happens on January 31. It might get as low as 30°F during the coldest months of winter.

Always keep in mind that USDA zone info for Diamond Bar is just an average and the actual date of last frost is different every year. Half of the time in Diamond Bar you get surprised by a frost after January 31 so always be ready to cover your leeks in the event of a surprise late frost.

USDA Zone Info for Diamond Bar

Here is the info for USDA Zone 10a.

Average Date of Last Frost (spring)	January 31
Average Date of First Frost (fall)	December 15
Lowest Expected Low	30°F
Highest Expected Low	35°F

This means that on a really cold year, the coldest it will get is 30°F. On most years you should be prepared to experience lows near 35°F.

Plants to Grow in Diamond Bar

You may be interested in your other planting guides for Diamond Bar.