1、 Improper fertilization

1. Reason: if there is no fertilization or insufficient fertilization for a long time during the growth period, yellow leaves will be caused. When fertilizing too much, Calendula is difficult to absorb excessive fertilizer, which will cause root burns and affect the absorption of water and nutrients

2. Treatment method: fertilize once a week in summer, and avoid excessive fertilization. If you fertilize too much, you can water more to dilute the fertilizer in the soil. Lack of fertilizer will lead to soil hardening. It is necessary to apply fertilizer immediately and take effect within a week, and then apply fertilizer on schedule to make the flowers grow normally

2、 Pest damage

1. Reason: the yellowing of Calendula leaves is often caused by mosaic disease, and yellow green mosaic spots will appear

2. Treatment method: pay attention to timely prevention of diseases, increase fertilizer and water management, spray medicine in time and give sufficient light and ventilation

3、 Plant water shortage

1. Reason: Calendula needs sufficient water during its growth. If it is not watered for a long time or watered too little, the plant will be short of water and the leaves will droop and turn yellow

2. Treatment method: at this time, spray water on the blades immediately, and then water the basin. Pay attention to watering step by step, and don't pour too much water at one time