Articles
Plant symptomology variation at low substrate pH
Article number
1391_81
Pages
599 – 604
Language
English
Abstract
Diagnosing plant nutritional disorders requires knowing the critical pH ranges and visual symptoms.
In several experiments, a range of substrate pH set points were used to determine the symptomology of low substrate pH. Experiments were conducted by incorporating increasing rates of dolomitic lime to peat-based substrates amended with 20% perlite (by vol.) thereby establishing substrate pH ranges for assessing plant growth and symptomology.
Responses to low substrate pH ranges can be classified into three groups.
Group 1, species such as Pelargonium × hortorum and Tagetes erecta, exhibit lower leaf bronzing and stippling.
Group 2, species such as Capsicum annuum, Dahlia hybrid, Solanum lycopersicum, and Zinnia elegans, exhibit lower leaf purplish-black discoloration.
Group 1 and 2 plants can be diagnosed with leaf tissue nutrient analysis to confirm the accumulation of excessive iron (Fe) and/or manganese (Mn) concentrations.
Group 3, species such as Euphorbia pulcherrima and Cannabis sativa, do not exhibit leaf symptomology but have less dry mass when grown at lower pH ranges.
Leaf tissue nutrient analyses revealed that Group 3 plants (E. pulcherrima and C. sativa) did not accumulate toxic iron or manganese concentrations in the leaf tissue.
Therefore, due to varying species-specific responses to low substrate pH, growers should monitor substrate pH closely and determine leaf tissue nutrient concentrations to effectively diagnose visual symptomology and plant growth effects.
In several experiments, a range of substrate pH set points were used to determine the symptomology of low substrate pH. Experiments were conducted by incorporating increasing rates of dolomitic lime to peat-based substrates amended with 20% perlite (by vol.) thereby establishing substrate pH ranges for assessing plant growth and symptomology.
Responses to low substrate pH ranges can be classified into three groups.
Group 1, species such as Pelargonium × hortorum and Tagetes erecta, exhibit lower leaf bronzing and stippling.
Group 2, species such as Capsicum annuum, Dahlia hybrid, Solanum lycopersicum, and Zinnia elegans, exhibit lower leaf purplish-black discoloration.
Group 1 and 2 plants can be diagnosed with leaf tissue nutrient analysis to confirm the accumulation of excessive iron (Fe) and/or manganese (Mn) concentrations.
Group 3, species such as Euphorbia pulcherrima and Cannabis sativa, do not exhibit leaf symptomology but have less dry mass when grown at lower pH ranges.
Leaf tissue nutrient analyses revealed that Group 3 plants (E. pulcherrima and C. sativa) did not accumulate toxic iron or manganese concentrations in the leaf tissue.
Therefore, due to varying species-specific responses to low substrate pH, growers should monitor substrate pH closely and determine leaf tissue nutrient concentrations to effectively diagnose visual symptomology and plant growth effects.
Authors
B.E. Whipker, P. Veazie, P. Cockson
Keywords
iron toxicity, greenhouse, manganese toxicity, nutrient toxicity, plant nutrition
Online Articles (105)