One of the first steps you take when you are determining 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.

By reviewing the USDA zone info for Louisville you should be able to determine when it's the best time to plant onions.

Planting Calendar for Onions

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

Since onions are very cold tolerant you can plant them a lot earlier in the year than more sensitive plants.

The earliest that you can plant onions in Louisville 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 onions and expect a good harvest is probably September. Any later than that and your onions may not have a chance to really do well. If you are starting your onions indoors then you might be able to get away with starting them a couple of weeks earlier.

Last Frost Date

In Louisville the average date of last frost happens on March 15. It might get as low as 10°F during the coldest months of winter.

Just be sure to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Louisville and it is different every year. Since half of the time in Louisville you get surprised by a frost after March 15 be ready to cover your onions if you have one of those late frosts.

USDA Zone Info for Louisville

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 Louisville

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