Reading Water, Media and Tissue Tests Bodie V. Pennisi Extension Floriculture Specialist, UGA

What Do You Do If Your Pansies Look Like These?

Nutritional ? Nutritional ? Which nutrient(s) ? Which nutrient(s) ? Deficiency or toxicity ? Deficiency or toxicity ? Cause(s) ? Cause(s) ? Investigate:

Macronutrient- Related Problems

N Def: lower leaf yellowing (courtesy of Dr. Whipker, NCSU)

N Def: Lower leaf yellowing and loss (courtesy of Dr. Whipker, NCSU)

P Def: Lower leaf purpling (courtesy of Dr. Whipker, NCSU)

N Overdose: Upper leaf roll (courtesy of Dr. Whipker, NCSU)

High Nutrient Concentration in the Medium Causes Marginal Leaf Burn Water leaves the leaves via stomates, but the trace elements cannot escape. The effect is most pronounced at leaf margins where air movement causes the greatest evaporation.

Micronutrient- Related Problems

Mg Def: Lower leaves with interveinal chlorosis

Problems Mg Def: Lower leaves with interveinal chlorosis (courtesy of Dr. Whipker, NCSU)

Fe Def: Upper leaves with interveinal chlorosis

It Is All About the pH… At high pH the micronutrients (Fe, Mn, B, Zn, Cu) become less available. At low pH, they become too available.

lime incorporated lime incorporated water alkalinity and pH water alkalinity and pH type of fertilizer used (basic or acidic) type of fertilizer used (basic or acidic) species grown species grown Media pH is affected by:

Geranium Group Geranium Group Plants that are very efficient in taking up Fe Plants that are very efficient in taking up Fe Ex: seed and zonal geraniums, marygolds, New Guinea impatiens, lisianthus Ex: seed and zonal geraniums, marygolds, New Guinea impatiens, lisianthus Crops Can Be Placed Into Groups Petunia Group Petunia Group Plants that are very inefficient in taking up Fe Plants that are very inefficient in taking up Fe Ex: petunias, pansies, snapdragons, calibrachoa, vinca Ex: petunias, pansies, snapdragons, calibrachoa, vinca

Low pH

Geranium with chlorotic lower leaves which quickly turn necrotic (courtesy of Dr. Whipker, NCSU)

Lower leaves of pepper with black speckles (courtesy of Dr. Whipker, NCSU)

Lower leaves of marigold with yellow speckles (courtesy of Dr. Whipker, NCSU)

Lower leaves of cosmos with black speckles (courtesy of Dr. Whipker, NCSU)

High pH

Upper leaves with interveinal chlorosis (courtesy of Dr. Whipker, NCSU)

Upper leaves with interveinal chlorosis (courtesy of Dr. Whipker, NCSU)

Upper leaves with interveinal chlorosis (courtesy of Dr. Whipker, NCSU)

The Goal Is To Achieve A Stable Medium pH Over Time

Basic Tests  Concentration of the fertilizer solution  pH and soluble salts in the growing medium  Leaf tissue analysis  Water Quality

Testing the growing medium  EC (SS) and pH of the leachate  In-house tests can be done with the pour- through method  Sending samples to a lab: do not use the top 1 / 2 to 1 inch of the soil  NO 3 - -N, NH 4 + -N, P, K, Ca, Mg

0 to to to to to 2.3 > 2.3 1:2SME PourThru Indication 0 to to to to to 6.0 > to to to to to 7.8 > 7.8 Very Low LowNormalHigh Very High Extreme Different Methods to Measure EC

Marigold problem

Tissue analysis Marigold problem

Sending tissue samples for analysis  For routine analysis: young, but full-grown leaves near the top of the canopy  Rinse the leaves gently if fertilizer was applied with an overhead irrigation system  B, Ca, Fe, Mn, Zn (not readily translocated within the plant)  Younger leaves

Chrysanthemums  Upper leaves – N, Ca, S, Fe, B  Lower leaves – K, Mg, Zn  Upper or lower leaves – P, Mn  Middle leaves – Cu  Routine analysis – most recent fully mature leaf

Tissue Analysis  Concentrations of macro- and micronutrients  These analyses may or may not include recommendations, depending on the lab

Testing The Waters…

Water Quality Kit

Analytical Lab

1.Need test for alkalinity 2.Need Fluorine (F) and/or Chlorine (Cl) if high levels are suspected.

Summary of Basic Tests Fertilizer solution Fertilizer solution Greenhouse medium Greenhouse medium Plant tissue Plant tissue Water Water