When to Plant Tomatos in Knoxville, IA

One of the first steps you take when you are figuring out 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.

The first chance to plant tomatos in Knoxville can be determined by looking at the USDA zone info.


Planting Calendar for Tomatos

Frost tolerance for tomatos: Not tolerant of frost.
When to plant: After the last frost has passed.

Tomatos do not do well in cold weather which means that it is important to wait until it warms up after the last frost before you can plant them.

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

The earliest that you can plant tomatos in Knoxville 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 tomatos and expect a good harvest is probably August. You probably don't want to wait any later than that or else your tomatos may not have a chance to grow to maturity. If you are starting your tomatos indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

On average the last frost has passed is on April 15 in Knoxville. In the coldest months of winter you should expect an average low temperature of -15°F.

Since the USDA zone info for Knoxville is just an average the actual date of last frost is different every year. Half of the time in Knoxville you get a frost after April 15 so just be sure to be ready to cover your tomatos if you have a surprise late frost.

USDA Zone Info for Knoxville

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 Knoxville

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