What should be monitored to prevent over-fertilization in plants?

Monitoring nutrient levels is essential to prevent over-fertilization in plants. Over-fertilization can lead to a buildup of excess nutrients in the soil, which can harm plant health by causing nutrient imbalances, burning roots, and negatively affecting soil microbial activity. By regularly checking nutrient levels, such as nitrogen, phosphorus, and potassium, growers can ensure they are providing the right amount of fertilizer for optimal plant growth without exceeding necessary amounts.

In terms of other choices, while the watering schedule is important for overall plant health, it does not directly monitor the nutrient availability in the soil. Soil temperature can affect root growth and nutrient uptake but does not provide specific information about nutrient levels. Sunlight exposure is crucial for photosynthesis and plant development, but it does not help in assessing the risk of over-fertilization. Hence, focusing on nutrient levels is the best practice for avoiding issues associated with excessive fertilization.