Plant Fertilizer Guide — What, When, and How Much

Too much fertilizer kills plants faster than too little. Learn the basics of N-P-K, the right timing, and how to recognize and fix fertilizer burn.

Fertilizer replenishes nutrients that plants absorb from the soil over time. But more is not better — over-fertilizing is a common cause of root damage and plant decline.

The Big Three: N-P-K

• Nitrogen (N) — drives leaf and stem growth. Deficiency shows as yellowing older leaves.
• Phosphorus (P) — supports root development and flowering. Key for blooming plants.
• Potassium (K) — overall plant health and disease resistance.

When to Fertilize

Fertilize only during the active growing season: spring through summer (March–September). During autumn and winter dormancy, plants can't efficiently absorb nutrients — fertilizing causes salt buildup in the soil that damages roots.

Types of Fertilizer and How to Use Them

• Liquid fertilizer — fast-acting; dilute in water and apply monthly during watering.
• Slow-release granules — sprinkle on soil surface; breaks down over 3 months.
• Organic fertilizers — gentle and slow; compost, worm castings, and fish meal reduce over-fertilization risk.

Signs of Fertilizer Burn and How to Fix It

Brown, crispy leaf tips and white crust on the soil surface are signs of over-fertilizing. Flush the soil thoroughly with water (enough to drain out the bottom several times) or repot in fresh soil.

Always start at half the recommended dilution. Feeding weakly and frequently is safer than strong doses given occasionally.