Several weeks ago, I brought my citrus inside. I have my meyer lemon and variegated pink lemon trees each under their own 200 watt CFL. I have the lights on for an average of 12 hours per day in a room that gets some light, but no real direct sun. Temps are about 70 degrees w/50% humidity. I am noticing two changes in the feel and appearance of the leaves. They are becoming less supple/stiffer and the the veins seems to be darker green than the rest of the leaves which seem less dark green. The closer the leaves are to the light source the more noticable the changes. The taller branches of the meyer are about 5 inches from the bulbs; the variegated one is about 9 inches away from the bulb. I have not yet seen any leaf drop. Should I increase the distance between bulb & tree, reduce the number of hours or both? Thanks! Stephanie in Germantown

Hi Sephanie, your tree is fine, what you are seeing is natural. I noticed this thread on another forum, however, I NEVER post any advice on that forum. One has to be very guarded about following any "advice" that is given on any forum. I noticed one person said "I have no idea what's happening with your trees" then went on to offer "move the light away and add Epson Salts," another person advised "the Epsom Salts... may help..I'd also add Iron... Sounds like a deficiency" both are wrong, and the last advice if followed could well be harmful to your tree. Light intensity is rarely constant but varies with movement of the leaves as well as changes in the angle of the sun, cloud cover and other factors such as adding additional artificial light sources like your 200 watt CFL. Citrus leaves in high light intensities are smaller and THICKER and have more but smaller chloroplasts which are generally oriented parallel to the light source. This causes the leaves to feel thicker and is a light moderating mechanism which allows plants to tolerate very high light levels without the chloroplasts being destroyed by the higher light energy. On the other hand leaves in the shade are generally larger and thinner, or more supple, and have larger chloroplasts that are generally oriented at right angles to the light source so a high proportion of the incoming light can be captured and used in the process of photosynthesis. This is why plants grown in shade or plants that are moved into shade appear greener. It should be emphasized that plants growing under a higher level of shade, such as your room, may produce a visually acceptable top, but the root system will be limited and reduced stored energy resources will increase sensitivity to any stress encountered. It has long been observed that plants placed under shade, will remain a good green color longer. This is FALSE PROSPERITY since the plant may look greener due to the orientation of the chloroplasts, but the plant is actually becoming weaker and weaker internally. Your tree is fine, leave the lights alone, your tree is only adjusting the chloroplasts in the leaves. One last tip, you might consider placing a fan to blow against the tree so as to flicker the branches back and forth. This along with the light will develop a strong tree. I do congratulate you for noticing the changes in your tree. Few people would have noticed. Take care. - Millet

Millet,
Thank you so much for taking time to give me such a thorough and detailed answer. I have read and re-read it and will save it in my files. You're the best! Stephanie