The inner leaves of my gardenias turn yellow. Why do you recommend? is there a solution to this problem?
gardenias are evergreen shrubs, which in nature live in subtropical, or tropical, fairly warm and humid areas, in Asia, Africa and Australia; in the apartment and in the garden in Italy, varieties of Chinese origin or other Asian areas are generally cultivated, which can survive the cool autumn, but do not like excessively low temperatures, especially in the case of some particular cultivars. For this reason, in Italy many varieties of gardenias are to be considered to all intents and purposes houseplants, as they would not survive the rigors of winter, at least in the central north of the peninsula. These plants are not easy to grow, and to always have flowering and luxuriant plants it is necessary to have a nice green thumb and even a little time available. The leaves that turn yellow inside the shrub may be due to various causes, which I can point you, it will then be up to you to understand what the problems afflicting your gardenia specimen actually are. Often leaf yellowing, which occurs mainly between the leaves that are less ventilated and less luminous than the bush, is due to root rot; this type of pathology develops above all in plants that remain for a long time with a soil soaked in water: water stagnation favors the development of mold and fungi, which from the soil and through the roots enter the plant. And gardenia love a humid climate and fresh soil, this often leads to the error of watering them with great regularity, without checking the soil conditions; when we water, we always check that the soil of the plants is still not very humid, or we're going to suffocate the roots and favor the development of rot. Especially in the months with few hours of insolation, gardenia watering can be only sporadic, about once a week or every 10 days; at the arrival of spring, the plant will have more need for accula, but we always check the state of the soil before supplying watering. If the gardenia is placed in a without heated, remember to vaporize the crown often, in order to increase the environmental humidity, and next also keep it in a large saucer or vase cover, with at least 4-6 cm of clay and two or three cm of water, which will evaporate regularly, increasing humidity. The yellowing of the leaves can also be caused by poor ventilation, by an excessively dry and dry climate, by excess fertilization; consider that these plants should be grown in well-lit areas, with good ventilation, and need fertilizer every fortnight, from March to September, but not during the winter months. In addition to this, they are acidophilic plants, and therefore avoid watering with very calcareous water, or all the leaves of the shrub will tend to become progressively lighter in color.