One of the best tools that you have as gardeners to help us estimate your gardening schedule is the 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.

The first chance to plant leeks in Columbia can be figured out by referring to 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.

Since leeks are one of those plants that can tolerate quite a bit of cold weather you can plant them a lot earlier in the year than more sensitive plants.

The earliest that you can plant leeks in Columbia 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 leeks and expect a good harvest is probably September. Any later than that and your leeks may not have a chance to fully mature. If you are starting your leeks indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

In Columbia the average date of last frost happens on March 15. In the coldest months of winter you should expect an average low temperature of 10°F.

Remember that the actual date of last frost is not always accurate because it is based on the USDA zone info for Columbia and it is different every year. Since half of the time in Columbia you get surprised by a frost after March 15 be ready to protect your leeks if you have a late frost.

USDA Zone Info for Columbia

Here is the info for USDA Zone 8a.

Average Date of Last Frost (spring)	March 15
Average Date of First Frost (fall)	November 15
Lowest Expected Low	10°F
Highest Expected Low	15°F

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

Plants to Grow in Columbia

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