When to Plant Onions in Geneseo, IL

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.

You can determine when you can plant onions in Geneseo by using the USDA zone info.


Planting Calendar for Onions

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

Onions are one of those plants that can tolerate quite a bit of cold weather which tells us that you can plant them much earlier than more sensitive plants.

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

The earliest that you can plant onions in Geneseo 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. If you wait any later than that and your onions may not have a chance to grow to maturity. If you are starting your onions indoors then you might be able to get away with starting them a few weeks earlier.

Last Frost Date

On average all chance of frost has passed is on April 15 in Geneseo. You should expect an average low temperature of -15°F in the coldest months of winter.

Since the USDA zone info for Geneseo is an average the actual date of last frost is different every year. Half of the time in Geneseo there is a last frost after April 15 so always be ready to cover your onions in the event of one of those late frosts.

USDA Zone Info for Geneseo

Here is the info for USDA Zone 5b.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-15°F
Highest Expected Low-10°F

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

Plants to Grow in Geneseo

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