What causes leaf curl on cannabis?

Leaf curl on cannabis can be caused by several factors, including nutrient imbalances, environmental stressors, pests, or diseases. Nutrient deficiencies or excesses, particularly of nitrogen or phosphorus, can lead to curled leaves. Additionally, environmental factors like heat stress, low humidity, or improper watering can contribute to the issue. Pests such as aphids or spider mites can also cause leaf curling by feeding on the plant's sap.