Lockout
A cultivation term for impaired nutrient uptake even though nutrients are present, often associated with unsuitable pH, excess salts or root stress.
Nutrient lockout describes an uptake problem rather than proof that the root zone lacks fertilizer. High salt concentration, unsuitable pH, damaged roots and interactions among ions can all reduce nutrient availability or uptake.
Symptoms can resemble a true deficiency, so diagnosis should consider root health, solution and substrate pH, and electrical conductivity Electrical conductivity (EC) A measure of a solution's ability to carry electric current, used as a fast indicator of total dissolved ion concentration but not of any specific nutrient. before more fertilizer is added.