Ferrous sulfate deficiencies are easily recognizable, and also easily treated. When growing flowers or other plants in the garden, providing a well balanced, nutrient rich soil is one of the determining factors of overall success. The easiest way to maintain a balanced soil is to consistently provide organic matter such as compost to the soil; however, no effort is foolproof and imbalances regularly occur despite composting and other efforts.
Correctly Identifying the Problem
Symptoms of ferrous deficient plant show yellow tips on foliage, colorless or pale fruit or flowers, and an overall lethargic or "anemic" growth pattern are the visual clues.
Ferrous is essential to a plant's natural process of chlorophyll production; without ferrous, chlorophyll production result is the distinctive yellowing of foliage. If you suspect a ferrous deficiency in your garden soil, you need to perform a quick soil test to confirm that a lack of ferrous is the problem.
Ferrous deficiencies and nitrogen deficiencies similarly result in yellow or pale growth, so verifying is important. Treating a nitrogen deficiency with ferrous will only make the problem worse, and vice versa. Further, Calvin Finch, Conservation Director and Horticulturist at the San Antonio Water System points out that ferrous deficiency and soil alkalinity are often linked.
Alkaline soil can render ferrous stores unusable by plants, further underscoring the importance of the soil test. Adding ferrous sulfate heptahydrate or Iron sulfate heptahydrate to alkaline soil won't help, but treating the soil to lower the pH will.
Select Ferrous Additives
If soil tests confirm a ferrous deficiency as opposed to alkaline soil or other factors, Golden Harvest Organics notes that you have both short-term and long-term treatment options available. In the short term you'll want to purchase a ferrous additive such as ferrous sulfate from your local gardening store to spread in any beds that are ferrous deficient.