When to Plant Rhubarb in Knoxville, IA

Before planting it is a good idea to find your USDA Zone info to determine your garden schedule. The zone info helps tell us things like average date of last frost and lowest expected temperature for your area.

The best time to plant rhubarb in Knoxville can be determined by referring to the USDA zone info.


Planting Calendar for Rhubarb

Frost tolerance for rhubarb: Tolerant of some frost.
When to plant: Up to 5 weeks before last frost.

Since rhubarb do well in moderate cold you can plant them a little bit earlier in the year than other plants that might not handle the cold.

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

The earliest that you can plant rhubarb in Knoxville 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 rhubarb and expect a good harvest is probably September. Any later than that and your rhubarb may not have a chance to grow to maturity. If you are starting your rhubarb indoors then you might be able to get away with starting them a little bit earlier.

Last Frost Date

The average date of last frost is April 15 in Knoxville. You can expect an average low temperature of -15°F in the coldest months of winter.

Keep in mind that USDA zone info for Knoxville is not always accurate and the actual date of last frost will vary from year to year. Since half of the time in Knoxville last frost occurs after April 15 be ready to protect your rhubarb in the event of a 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.