Small yellowing of lemon seedling leaves

Discussion in 'Citrus' started by MadDawg_24, Dec 28, 2016.

  1. MadDawg_24

    MadDawg_24 New Member

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    Hello,

    I have a lemon seedling whose seed I planted about 6 months ago, in mid to late July 2016. Starting about 2-3 weeks ago I noticed the 2 lowest leaves were starting to turn yellow on the edge near the leaf tip. Before this, all the leaves were a beautiful green! What could the problem be, too much water, not enough water, not enough nutrients, or something else?

    I have also not seen any new growth in over a month, although I am a little less concerned about that since I've assumed it was due to the time of the year.

    I attached a few pictures so you can see the leaves for yourselves. In the last picture showing the entire seedling, it's only the lowest leaf that has a bit of yellow, the ones that are higher up look ok to me and the other leaf with a bit of yellow is hidden by another leaf.

    Based on a few other threads on these forums and articles on other websites that I read, here are details about my lemon seedling that could help the diagnosis.

    -The seedling is about 5" tall starting from the soil level and it has only 5 leaves. The leaves are all between approximately 1" and 2" in length and about 1" in width.

    -The seedling is in a plastic pot, 6" wide and 4 1/2" high.

    -The dirt is nothing special. It is cheap dirt from a hardware store like The Home Depot. When I say cheap dirt, I mean 5$ for a 50L bag. I don't remember if it was top soil or potting soil but it's definitely not dirt targeted for citrus trees.

    -For fear of burning the seedling since it is still so small, I have not put any fertilizer since I planted the seed. I do have some Jobe's fertilizer spikes (13-4-5 nitrogen-phosphoric acid-potash) I can put in if really needed, but again, I am fearful of burning the seedling. The instructions on them are 1 spike for every 5cm or 2" of pot diameter.

    -I estimate I water every 5-7 days and I generally do not water until water starts to come out the bottom of the pot.

    -The temperature in my living room is generally 20-24 Celsius, or 68-75 Fahrenheit. Is it too cold?

    -The seedling has spent it's entire life indoors on my coffee table in direct or indirect sunlight. The nearby windows face North and West. There's no possibility to put the seedling in an East or South facing window since there are none in my condo. At first the seedling was getting 8+ hours of light per day but now that it is wintertime, the seedling is getting a max of 6 hours of light per day. This week I have put the seedling on the windowsill of a West facing window, thinking it needed more direct sunlight. Should I buy a lamp for it? If yes, what type of light do I need, florescent? How high above the top of the seedling should I hang the light, 6-8"?

    -My plan for the seedling is to permanently keep it indoors, even when it is a few years old and a few feet tall.

    -I brought the seeds back from Capri Italy, and I have no idea what variety it is. I only know that the lemon it came from was bigger than my fist, a huge lemon compared to what I see in the local grocery stores!

    Thanks for any feedback!

    -Matthew
     

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  2. Junglekeeper

    Junglekeeper Contributor 10 Years

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    It looks like the yellowing is in the seedling's first set of leaves, which I suspect are about to be shed. Don't worry about it unless the true leaves are affected. Not seeing top growth for a period is normal for citrus as development typically alternates between vegetative and root growth. Also, as you have noted, it could simply be reduced activity as the result of having less light at this time of year.

    Be careful not to over-water, especially since a 6" pot is somewhat big for a seedling. Only water when the soil has become somewhat dry. Your room temperature should be fine. Place the tree behind the west window; there'll be more light there than the north window.

    I prefer to use a water-soluble fertilizer that includes micronutrients. It might be an idea to crush the spikes which you have and just sprinkle a bit of that onto the soil and mix it in.

    As for the soil, you may want to go with a more porous mix when it comes time to repot. You can use what you have now and amend it with medium sized bark chips, perlite, and/or calcined clay.
     
  3. MadDawg_24

    MadDawg_24 New Member

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    Some of the other leaves are starting to get a little yellow now too so I took your advice and broke up one of the spikes and sprinkled some on top and mixed it in. Well, actually I broke up about 1/2 a spike. and mixed it in. I'm still a little scared to burn it from too much fertilizer. I'll see how it handles this, and if in a week or two the leaves continue to yellow I'll put the remainder of the spike in like I would normally do for a bigger plant. I rather do two small batches to avoid burning it but hopefully still manage to save it.

    When you say "it looks like it is in the seedling's first set of leaves, which I suspect are about to be shed", isn't this a bad thing for such a small seedling? How will it survive if it loses its first leaves? How can I tell the difference between the first set of leaves and the "true leaves"? To me, they're all the first set of leaves since it's so small and young.

    If the seedling continues to grow or at least survive the winter, I'll look into getting some better soil. But that might be a while since you say a 6" pot is a bit big for a seedling.

    Thanks for the info!

    -Matthew
     
  4. Junglekeeper

    Junglekeeper Contributor 10 Years

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    Do not continued to fertilize if the yellowing does not stop; it would only makes things worse if the tree is stressed. The seed leaves are shed once they have served their purpose of providing the seedling with energy until true leaves develop. Notice they're of a different shape, slightly rounded.
     
  5. MadDawg_24

    MadDawg_24 New Member

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    Hi,

    Ah, so by first set, you really meant the first two leaves and not the first dozen or so. Gotcha. I did notice some leaves were more rounded than others and I figured it was because it was the first few leaves and they would naturally be smaller. The different shape was a bit of a surprise, but not alarming to me.

    A small update: The leaves with some yellow do not appear to be getting more yellow, but it's hard to tell as I haven't been taking pictures each week. Also, a new leaf has started growing! Based on the photos I have, it's the first new leaf since September!

    Thank you again for the replies.

    -Matthew
     
  6. MadDawg_24

    MadDawg_24 New Member

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    Hi again,

    Quick update: the first leaves that showed some yellow aren't really getting any worse, there's been some new growth, of which some of the leaves are also showing some yellow, and there are even two leaves with one brown spot each, and the latest new growth looks perfectly healthy.

    Thoughts?

    -Matthew
     

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  7. Junglekeeper

    Junglekeeper Contributor 10 Years

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    I wouldn't worry at this point. There appears to be a bit of yellowing in the leaf tip in one of the big leaves. If it is the result of some deficiency, it should resolve itself if you feed regularly with a fertilizer that includes micronutrients.

    Here is a document that may be of interest: HS-797/CH142: A Guide to Citrus Nutritional Deficiency and Toxicity Identification

    There's some white substance near the edge of the pot in the bottom right quadrant. That could indicate an accumulation of salt in the soil. That can be removed by flushing the soil with water.
     
  8. MadDawg_24

    MadDawg_24 New Member

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    Hmm maybe it wasn't the best of pictures, but it's not just the one big leaf that is yellowing. There are more leaves yellowing than not, and two leaves even have one small brown spot each. I picked up a 20-8-20 water soluble fertilizer that contains micronutrients, although I can't say off-hand how much of what.

    Thanks for the guide, nice find! I'll save that for future use.

    Yes, those white deposits are probably some salt from the city tap water. Is it the best thing to do to flush the soil when I'll only be adding more salts, and I may already be over watering?

    -Matthew
     
  9. Junglekeeper

    Junglekeeper Contributor 10 Years

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    It would be better to use a fertilizer with a ratio closer to 5-1-3; I use a 30-10-10. It should be all right as long as micronutrients are included; they occur in trace amounts anyway.

    Flushing helps to clear accumulated salts from the medium; whatever amount remains from the water is small compared to the that being flushed out. If you flush at a time when the plant needs watering then the soil will be wetter than usual only a little longer than usual. It should be all right if the medium is porous, as it should be for citrus. If not, I suggest you replace it with one that is.
     

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