First, improper moisture.

A, watering too much, in this case, the young leaves of gardenia are dark yellow and dull, and the old leaves have no obvious change. At this time, just take the flowers out of the pot and put them in a ventilated and cool place, and then put them back when the soil is dry.

B, when lack of water, the leaf tip or edge withers and dries, and the old leaves wither and fall off from bottom to top, but in this case, the growth of new leaves is relatively normal. At this time, it is necessary to pour enough water and make it permeable.

Second, improper lighting.

A, the light is too strong, and yellow spots appear in the sunrise part of the leaves. At this time, you only need to move it to the shade to maintain it, and the newly grown leaves will not have yellow spots.

B, the sun is insufficient, then the leaves will turn yellow or even fall off, just put them in the sun to supplement the sun.

Third, improper fertilization.

A, excessive fertilization, mainly in the top of the new leaves appear brown, thick and dull leaves, old leaves brown off. At this time, fertilization should be stopped immediately, and the soil should be washed to reduce the concentration in severe cases. B, lack of fertilizer, lack of fertilizer can also lead to yellowing of plants, such as iron deficiency, pale yellow or white leaves, and green veins. At this time, 0.2%-0.5% ferrous sulfate water should be sprayed for control; Without magnesium, the old leaves turn yellow first, the new leaves turn yellow again, and the veins are still green. At this time, 0.7%-0.8% boron and magnesium fertilizer can be sprayed for control.

Fourth, too low a temperature will also cause the leaves to turn yellow, just move to a high temperature.