My Castor Bean Plant Is Dying

Temperature

• Castor bean seeds are resistant to the cold, but the plants themselves are highly sensitive to extreme temperatures. Coupled with the relatively long 140- to 180-day growing season, this can leave a somewhat small window in which to plant the castor bean seeds depending on your local climate. Castor bean plants die if exposed to temperatures below freezing, so planting should only occur a week or two after the final frost of the season. They are slightly more resistant to heat, but will wither if exposed to several days of more than 100 degrees Fahrenheit.

Weeds

• Another problem that arises from the slow growth of the castor bean plant is a susceptibility to weeds that can choke off the plant from nutrients. Regular rotary hoeing should take care of the weed problem, but make sure not to hoe too deep, as the castor bean plant's root system is a shallow one. Hoeing to a depth of only 2 to 3 inches should be sufficient.

Disease

• Castor bean plants are vulnerable to most of the same diseases and infestations as other shallow-rooting garden plants. Especially in areas of high moisture, fungal infestations are usually the most destructive. Inspect the dying plants for spots or molds and immediately remove any plant showing signs to prevent the infestation from spreading. Treating the seeds with a fungicide such as Thiram before planting can also make the plant more resistant to fungal disease.

Pests

• Castor bean plants are resistant to attacks from stem- and leaf-feeding insects. However, if your castor bean plant is dying you may want to check for worm infestation. Cut worms and wire worms can destroy stands, cutting the rest of the plant off from vital nutrients. Plants that have been attacked by worms should be removed and disposed of immediately. Pesticides can also be effective in controlling worms.