Why Does My Nasturtium Always Have Yellow or Dying Leaves?

Summer Heat

• Like many annuals, nasturtiums don't tolerate intense summer heat. The foliage and flowers may become ragged, yellowed or dried. Water the plants a bit more during summer heat. The plants will recover once cooler temperatures return. Plant nasturtiums in partial shade if you live in an area with long, hot summers. Move potted nasturtiums to a shaded location.

Soil

• Nasturtiums tolerate most soil types, as long as the soil drains well. Yellow leaves may be caused by heavy soil that lacks proper drainage. Under these conditions, the plants may not receive enough oxygen, causing the roots to rot. Amend heavy soils with compost or manure, or choose another location.

Insects

• Leaf-sucking insects, such as aphids and leafhoppers, may cause the leaves to become distorted or yellowed. Look for the insects on the undersides of the leaves. Honeydew, a sticky substance these pests secrete, will be evident on the leaves as well. Remove dead leaves and spray the plant with insecticidal soap, coating the leaves well.

General Recommendations

• Nasturtiums are usually low-maintenance plants that thrive in somewhat dry, infertile soil. Plant them in full sun to partial shade and don't give them extra fertilizer, which promotes foliage at the expense of blooms. Start nasturtium seeds indoors six to eight weeks before the last frost or plant them outdoors in early summer.