Symptoms of Iron Deficiency
Roberto G. Lopez, Ph.D., Assistant Professor & Floriculture
Extension Specialist, Purdue University
Symptoms of iron (Fe) deficiency typically
appear as interveinal leaf chlorosis (Figure 1) on shoot tips
and then progress throughout the entire plant. In extreme case, the leaves of some plants
will turn almost white (Figures 2 and 3). Fe deficiency can
be prevented by controlling pH and alkalinity and using an iron
chelate fertilizer. Irrigation water with high alkalinity
(commonly found in the Midwest) typically has a high pH. Many
micronutrients, including Fe, are not available to plants when
the root zone pH is high. The acceptable pH range for plants that
are susceptible to iron deficiency such as calibrachoa, pansy,
petunia, scaevola, snapdragon (Figure 4), and sutera is between
5.5 to 5.8. Growers can lower substrate pH by acid injection.
They can also apply
iron sulfate or iron chelates such as Sprint 330® (10%
iron) or Sprint 138® (6% iron) to "green up" plants quickly.
Click image to enlarge
Figure 1. Petunia with interveinal chlorosis due to high pH.
Figure 2. The yellow to white foliage in this calibrachoa is an
iron deficiency due to high substrate pH.
Figure 3. Iron deficiency in Northern sea oats (Chasmanthium
Figure 4. Iron deficiency in snapdragon.