Wilting despite watering

Wilting in moist soil usually means diseased roots: overwatering with root rot or phytophthora damage the roots, so the plant cannot take up water despite it being present. It can also be a vascular wilt (fusarium, verticillium) that clogs the conducting vessels. Lift the plant and check the roots – healthy ones are pale and firm, diseased ones brown and soft.

Vascular wilt is caused by soil fungi (fusarium, verticillium) that enter through the roots and block the water-conducting vessels. The plant wilts despite moist soil, often on one side first, and cutting the stem reveals brown discolouration of the vessels. The disease is hard to cure, so infected plants are usually removed.

With drought the soil is dry and the plant recovers within hours of watering – a reversible wilt. With root rot the soil is wet, the roots brown, soft and foul-smelling, and watering only makes it worse. The key is to check soil moisture and inspect the roots before deciding whether to water.