Hi I have had a small lemon tree for about a year. I has been fairly happy and grown quite a lot in the year. In the last week or two it has started to drop leaves and has lost about half of them. Some of the leaves have brown blotches and appear limp near the end. The plant is on a north facing window sill and has been happy for a year. It has been given regular citrus feeds. Help.
Hi Killer App, I am not an expert on diseases, but I have learned a lot from theses forums. Since you said you have the tree in a North facing window, it is unlikely to be suffering from the most common cause of winter leaf drop-- cold roots while being exposed to direct sun. The second most common cause is overwatering. This sometimes happens when the same watering schedule is used -- as the soil gets older it compacts and does not dry as rapidly and also exludes air leading to root rot. You can check for this by carefully pulling the tree out of the pot and looking at the roots-- they should be a cream/tan color--if they are brown and mushy you have root rot. One other thing that could be a problem is salt accumulation. Depending on your water supply, there could be salts in the water that buildup in the soil. This can be helped by flushing the soil-- running several volumes of water through the pot to leach out any salts. Other than that it could be a disease that I am not familiar with. Skeet
Hi skeeterbug Thank you for your reply. I have looked at the roots and 'cream/tan' is a fair description of them, so it looks like its nor root rot. When I looked the soil at the base seemed slightly moist and about what I expected. I have flush about a bucket of water through the pot so hopefully any salt buildup has gone. The window never gets any sun it seemed happy last summer and trippled in size -- do you think the plant should given sunlight? A friend who had a similar plant said the hardy ones disliked direct sun.
They do like direct sun for at least part of the day during the growing season, and would probably need some sun to produce fruit. If you can put it outside durring the summer it would probably do better--you will have to adapt it to direct light if it has not had any. Just expose it to an hour or so at a time for the first few days and then increase that slowly. However, during the winter when it is inside, if the roots are below 55 F they are completly dormant and if the tree is exposed to sun when the roots are dormant it will kill the leaves. Since roots are good, that eliminates root rot. Salt buildup is still possible, one typical symptom of salt buildup is brown leaf tips. You may need to flush the soil even more than you have in the long run. You should plan of flushing the soil at least a couple times each year-- you can put it in the shower or just let a hose run into the pot for a while (outside of course). Outside of that, I am out of ideas. Skeet
Some more leaves did fall of the tree and it now looks a bit sorry for itself... however, there are small new shoots forming so maybe its is feeling a bit better now :D The tree looks more like a broken umberella than a tree, it does not have a main trunk of any size. Should it be trained at all?
In general citrus trees do not need any pruning. Since it is a container tree you may need to prune to keep the size managable in the long run--- to fit within whatever space you have, but I would not prune unless absolutly necessary. Skeet
I have also learned a lot from this forum, more than days of surfing. But a local plant shop owner told me my lemon leaves were falling because of pests. -I showed her leaves, and she said the tiny black marks were from infestation. I applied the spray she gave me. The few leaves I had left did stay intact. But my room temperature is 65, even lower when we were out of town. So now I think it must be the cold root sun exposure dynamic as well.
Most people do not think about it, but there are several factors that can cool the roots of a tree below the ambient room temp. Evaporation--especially from a clay pot, cold air falling from a window, contact with the floor--which is probably the coldest part of the room, in addition if the sun is shining into the room-- the pot is often below the window sill and not being warmed like the rest of the room. Skeet
