Plant Nutrition

Soluble salt injury on begonia

Which begonia has been overfertilized? No foliar symptoms here. The small plants turned out to have very high electrical conductivity (EC) compared to the larger ones due to poor mixing of slow-release fertilizer. In short, a soil test is almost always needed to confirm a soluble salts problem. High growing medium EC can injure or inhibit the growth of plants. Common causes of high EC include: excess fertilizer (too high level or too frequent application), subirrigation, root disease, or restricted drainage.

Molybdenum deficiency on poinsettia

Molybdenum deficiency begins as a yellowing along poinsettia leaf margins, especially on leaves in the middle of the plant and upward. Leaf margins become brown and necrotic. Leaves may also pucker downward. 'Marblestar' commonly exhibits marginal chlorosis that may indicate molybdenum deficiency.

To prevent molybdenum deficiency, check media pH and use poinsettia fertilizer blends that contain sufficient molybdenum. Molybdenum deficiency is more likely to occur when the pH is low (pH of 5.3 or lower).

Iron deficiency on petunia

Iron deficiency symptoms show up as interveinal chlorosis, normally starting at the shoot tips, but often occur throughout the plant. Sometimes the leaves turn almost white. Bacopa, calibrachoa, scaevola, snapdragons, and petunia are susceptible to iron deficiency. These are crops that favor media pH below 6.0. Prevent iron deficiency by controlling pH and using an iron chelate fertilizer. The photo here shows petunias beginning to grow out of deficiency symptoms. Notice the darker green color of the new growth. The pH and fertility have been adjusted.

Iron deficiency on petunia

Iron deficiency symptoms show up as interveinal chlorosis, normally starting at the shoot tips, but often occur throughout the plant. Sometimes the leaves turn almost white. Bacopa, calibrachoa, scaevola, snapdragons, and petunia are susceptible to iron deficiency. These are crops that favor media pH below 6.0. Prevent iron deficiency by controlling pH and using an iron chelate fertilizer.

"How to Prevent Iron Deficiency in Spring Greenhouse Crops"

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