When to Plant Tree onions in Louisville, KY

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 USDA zone info for Louisville can be reffered to in order to determine when it's possible to plant tree onions.


Planting Calendar for Tree onions

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

Tree onions are barely cold tolerant which means that you can start planting them slightly earlier than more sensitive plants.

JanFebMarAprMayJunJulAugSepOctNovDec
Legend 
A good time to plant tree onions
Possibly ok, but a risky time to plant tree onions
Probably not a good time to plant tree onions

The earliest that you can plant tree onions in Louisville is March. However, you really should wait until April if you don't want to take any chances.

The last month that you can plant tree onions and expect a good harvest is probably August. Any later than that and your tree onions may not have a chance to fully mature. You can get started a little bit earlier by starting your tree onions indoors.

Last Frost Date

On average the last frost is on April 15 in Louisville. It might get as low as 0°F during the coldest months of winter.

Always keep in mind that USDA zone info for Louisville may not be accurate from year to year and the actual date of last frost is different every year. Half of the time in Louisville it frosts late in the year after April 15 so make sure that you are ready to protect your tree onions if you have a late frost.

USDA Zone Info for Louisville

Here is the info for USDA Zone 7a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low0°F
Highest Expected Low5°F

This means that on a really cold year, the coldest it will get is 0°F. On most years you should be prepared to experience lows near 5°F.

Plants to Grow in Louisville

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