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I have a lemon that I grew from store bough lemon seed so it's not a dwarf variety. It was growing crazy fast but now it started to drop leaves, some seemed healthy other had some browning around tips and edges.

Enviroment:

  • Constant 19-24C
  • Low humidity
  • Mostly overcast daylight
  • Water 2-3 times a month (with general purpose nutrients)

Roots seem to grow very slowly and have not yet reached the bottom of the pot. It was only transplanted once. Plant is only a few months old.

I have been adding tea leaves which is the only major change I can think of. It doesn't look like high ph symptoms from other resources though. I haven't added anymore for a while or watered for maybe 3-4 weeks - symptoms do not appear to have spread or gotten worse. Perhaps it was over watered but again symptoms don't seem to match.

What is the likely cause and the solution?

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DominicM
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  • What sort of soil is the lemon tree in? – Graham Chiu Jan 14 '18 at 19:15
  • Nothing special, compost with some worm castings. It did very well up to now so I don't think soil is an issue. – DominicM Jan 14 '18 at 21:14
  • Has there been any sudden change in the amount of light the tree receives? – Jurp Jan 14 '18 at 21:37
  • @Jurp Sorry for late reply. Not really, it's inter and very bad weather lately but that's not uncommon – DominicM Jan 15 '18 at 18:56
  • The reason I ask is that when I put my Clementine orange (from seed) outside in the Spring in too much sun it drops its leaves; when I bring it inside for the winter, it drops its leaves. They always regrow. I water my orange maybe once a month, and only if the pot is light - well, as light as a clay pot with a 4' tree in it can be :) – Jurp Jan 17 '18 at 01:10

1 Answers1

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Diagnosis through photos is hard so I hope you will find it useful if I point out what I do not see:

  • no sign of white grains of salt on the underside of the leaves which indicate spider mites which are a common problem.
  • no scale or mealy bug observed, thrip would be unusual outside of a greenhouse and there is no telltale frass or silvery tracks on the leaves => no pests
  • no sign of green veins and yellow leaves which are typical of an iron/manganese deficiency due to alkaline soil

The item that may be causing this is overuse of fertilizer. Yes, outdoors in a high light situation you would have to work hard to over fertilize. Indoors where light levels are ten to a hundred times lower fertilizing two to three times a month is too much.

I suggest watering once with distilled water in sufficient quantity that water runs out the bottom of the pot. This will reduce the fertilizer salts that may present in the soil. Then switching to a citrus fertilizer or similar that has chelated iron and manganese. Apply once every two months at half strength in fall and winter. During spring and summer apply at half strength every month.

kevinskio
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  • there does appear to be browning at the edges on one of the pictures suggesting fertilizer burn. – Graham Chiu Jan 14 '18 at 21:57
  • Also for citrus trees it is important that they have dry spells. Overwatering will cause the leaves to curl up. – Tikkes Jan 15 '18 at 10:27
  • That's a no to all the points. Fertiliser burn seems plausible. Could over watering also cause brown leaf edges? What about acidic soil from tea leaves? – DominicM Jan 15 '18 at 19:15
  • @GrahamChiu Yes the main symptom is browning leaf edges closest to tips, then often drops. Any good resources relating to this? – DominicM Jan 15 '18 at 19:17
  • Citrus likes acidic soils. – Graham Chiu Jan 15 '18 at 19:24
  • https://www.houzz.com/discussions/3355225/why-is-my-lemon-tree-getting-burnt-leaf-tips – Graham Chiu Jan 15 '18 at 19:54
  • @GrahamChiu Images in the link show yellowing but in my case there is absolutely no yellowing anywhere. I know lemons like acidic soil but maybe it's too acidic, would symptoms be browning leaves? – DominicM Jan 16 '18 at 13:46
  • Easy enough to test. Get a soil testing kit to check the pH. But even though tea can have a pH down to 4.9, I doubt tea leaves on the surface would alter the pH that much. – Graham Chiu Jan 16 '18 at 20:30