Brown Spots on a Jade Plant

Crassula ovata, the jade plant, is a popular indoor houseplant. As with other succulents, the jade plant requires relatively little care yet is still susceptible to a few plant disorders and pests. One of the more common problems associated with the jade plant is the appearance of brown spots on the leaves. Often, these brown spots are easily preventable simply by not overwatering your plant.

Oedema is not a plant disease but a physiological disorder that occurs when plants receive too much water. Because the plant cells cannot use all of the water, they tend to expand, forming unsightly brown bumps that look like corky blisters on the leaves of the jade plant. In extreme cases, if left untreated, Cornell University Plant Disease Diagnostic Clinic notes that the brown spots associated with oedema can even spread to the stems.

Several strategies can be employed to reduce the effects of oedema. Succulents should not be watered too frequently. The Missouri Botanical Garden recommends allowing the soil or potting mix to dry before watering the plant again.

Oedema is a more common occurrence during the cool seasons. In fall and winter, jade plant has a reduced need for water, so if you continue to water at the same rate as you did in spring and summer, it may be too much. Reduce the amount of water you give your jade plant in fall and winter, allowing the soil to dry before only lightly watering it again.

Planting the jade in a pot that drains well will lessen the likelihood that the plant will suffer from oedema, and so will making sure that the plant has enough sun to aid in drying out the soil. Remember, it is never a bad idea to remove leaves that are obviously dying; this ensures that the plant does not needlessly divert nutrients in an effort to save dying leaves.

Two pests common to the jade plant are spider mites and mealybugs. If soil conditions or location do not seem to be the cause of the brown spots, it is likely that one of these two pests is the culprit. A magnifying glass should be used to scour the plant for spider mites, as they are very tiny and difficult to see with the naked eye. One sign of mealybugs is a white, cottony build-up along the stems or in the leaf crotches.

A jade plant owner should avoid peat-based fertilizers and ensure that the plant is draining properly, as soggy soil can lead to an infestation of mealybugs. For a minor infestation, use an alcohol-dipped swab to dab mealybugs off your plant. If the infestation is severe, you can press imidicloprid spikes into the soil around your jade plant, being sure to follow all label recommendations.

Use a spray bottle on the stream setting to aim water at spider mites to dislodge them from your plant. It is important not to use any sprays or insecticides containing pyrethrin, such as insecticidal soap, on a jade plant.