When to Plant Sweet Potatos in Alton, IL

One of the first steps you take when you are getting a good idea 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.

One way of getting a good idea when to plant sweet potatos is to refer to the USDA zone info for Alton.


Planting Calendar for Sweet Potatos

Frost tolerance for sweet potatos: Not tolerant of frost.
When to plant: After all chance of frost has passed.

Since sweet potatos do not do well in cold weather it is necessary to wait until after the last frost has passed before you can plant them.

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

The earliest that you can plant sweet potatos in Alton is April. However, you really should wait until May if you don't want to take any chances.

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

Last Frost Date

The average date of last frost is April 15 in Alton. It might get as low as -10°F during the coldest months of winter.

It's important to remember that the actual date of last frost is just an average because it is based on the USDA zone info for Alton and it can change quite a bit from year to year. Half of the time in Alton you get surprised by a frost after April 15 so always be ready to cover your sweet potatos in the event of a surprise late frost.

USDA Zone Info for Alton

Here is the info for USDA Zone 6a.

Average Date of Last Frost (spring)April 15
Average Date of First Frost (fall)October 15
Lowest Expected Low-10°F
Highest Expected Low-5°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 -5°F.

Plants to Grow in Alton

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