Reading Water, Media
and Tissue Tests
Bodie V. Pennisi
Extension Floriculture Specialist, UGA
What Do You Do If Your Pansies Look Like These?
Investigate:
•
Nutritional ?
•
Which nutrient(s) ?
• Deficiency
• Cause(s)
?
or toxicity ?
MacronutrientRelated
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.
MicronutrientRelated
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.
Media pH is affected by:
•
lime incorporated
•
water alkalinity and pH
•
type of fertilizer used (basic or
acidic)
•
species grown
Crops Can Be Placed Into Groups
•
•
Geranium Group
•
Plants that are very efficient in taking up Fe
•
Ex: seed and zonal geraniums, marygolds,
New Guinea impatiens, lisianthus
Petunia Group
•
Plants that are very inefficient in taking up
Fe
•
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
(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)
Upper leaves with interveinal chlorosis
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 pourthrough method

Sending samples to a lab: do not use the top 1/2
to 1 inch of the soil

NO3--N, NH4+-N, P, K, Ca, Mg
Different Methods to Measure EC
1:2
SME
PourThru Indication
0 to 0.3
0 to 0.8
0 to 1.0
Very Low
0.3 to 0.8
0.8 to 2.0
1.0 to 2.6
Low
0.8 to 1.3
2.0 to 3.5
2.6 to 4.6
Normal
1.3 to 1.8
3.5 to 5.0
4.6 to 6.5
High
1.8 to 2.3
5.0 to 6.0
6.6 to 7.8
Very High
> 2.3
> 6.0
> 7.8
Extreme
Marigold
problem
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

Greenhouse medium

Plant tissue

Water