Why Petunia Leaves Turn Light Green

Light green leaves on petunias usually signal overwatering. Excess moisture saturates the soil, preventing roots from absorbing essential nutrients like nitrogen, phosphorus, and iron. Petunias only need about 1 inch of water per week — more during hot spells above 85°F with no rain.

To fix the problem, amend the soil with organic matter such as compost, humus, or aged manure to improve drainage and nutrient retention. Supplement with a water-soluble fertilizer containing iron to restore deep green foliage. Always water deeply but infrequently to encourage strong root growth.