Common Nutrient Deficiencies and How to Fix Them

Nutrient deficiencies are among the most common problems growers face. The good news is that most deficiencies are easy to identify and fix once you know what to look for.

How to Identify Deficiencies

Before diagnosing a nutrient deficiency, first check these common causes:

1. pH is out of range — The #1 cause of apparent deficiencies. Even if nutrients are present, plants can't absorb them at the wrong pH. Target 5.5-6.5 for hydroponics, 6.0-7.0 for soil.
2. Overwatering — Can cause symptoms that mimic nutrient deficiency
3. Root problems — Root rot or damage prevents nutrient uptake

Common Deficiencies

Nitrogen (N) Deficiency

Symptoms: Lower leaves turn uniformly pale yellow, then die. Growth slows dramatically. Fix: Increase nitrogen in your feeding schedule. For quick correction, use a dilute foliar spray with a nitrogen-heavy solution (avoid strong concentrations to prevent leaf burn). Follow up by increasing nitrogen in your regular feeding schedule to address the root cause.

Phosphorus (P) Deficiency

Symptoms: Dark green leaves with purple/reddish stems and undersides. Slow growth. Fix: Check pH first (phosphorus locks out below pH 5.5). Add a phosphorus-heavy supplement.

Potassium (K) Deficiency

Symptoms: Brown, crispy edges on older leaves. Leaves may curl or look scorched. Fix: Add potassium supplement. Common in flowering plants with high K demands.

Calcium (Ca) Deficiency

Symptoms: New growth is distorted, crinkled, or shows brown spots. Growing tips may die. Fix: Add a calcium-magnesium supplement. Common in soft water areas and coco coir growing.

Magnesium (Mg) Deficiency

Symptoms: Interveinal chlorosis — leaves yellow between the veins while veins stay green. Starts on lower leaves. Fix: Foliar spray with Epsom salt (magnesium sulfate) at 1-2 tablespoons per gallon of water for a quick fix. Add a calcium-magnesium supplement to your regular feeding schedule for ongoing correction.

Iron (Fe) Deficiency

Symptoms: Similar to magnesium but starts on NEW growth. Young leaves turn pale yellow/white between veins. Fix: Check pH (iron locks out above 6.5). Add chelated iron supplement.

Prevention Is Better Than Cure

• Monitor pH at every watering
• Use a complete nutrient solution designed for your growing method
• Don't overfeed — excess of one nutrient can lock out others
• Keep records of what you feed and when

Truleaf Can Help

Our Plant Database includes specific nutrient requirements for 350+ plant species, and the Nutrient Manager helps you mix the right nutrients at the right ratios for your specific plants and growth stage.