Nutrient deficiency question

Please see attaached....it is a leaf from my Key Lime....I am unsure as to whether this is characteristic of an iron deficiency or something else...the venation is really dark green with accompanied generalized yellowing Thanks in advance for your input.

Regards,
Tom

It's been a long time since I had a lime. Are the dots normal? Citrus are very prone to iron deficiency anemia, seen as chlorosis. You can get iron tonic at the garden center. Also feed Miracid regularly.
Iris

Hi, Iris....thanks for your reply...regarding the dots, they are the result of a camera glitch...I do have chelated iron and will follow your advice regarding Miracid....many thanks.

Regards,
Tom

When I had this my google reasearch came up with this;
Sulfur is a structural component of amino acids, proteins, vitamins and enzymes and is essential to produce chlorophyll. It imparts flavor to many vegetables. Deficiencies show as light green leaves. Sulfur is readily lost by leaching from soils and should be applied with a nutrient formula. Some water supplies may contain Sulfur.
Magnesium is a critical structural component of the chlorophyll molecule and is necessary for functioning of plant enzymes to produce carbohydrates, sugars and fats. It is used for fruit and nut formation and essential for germination of seeds. Deficient plants appear chlorotic, show yellowing between veins of older leaves; leaves may droop. Magnesium is leached by watering and must be supplied when feeding. It can be applied as a foliar spray to correct deficiencies.
Cheers G

Hello Tom – you’ve gotten good advice so far.

As to the dots, they are pellucid glands that are characteristic of plants in the genus Citrus and many other plants in the Rutaceae (the rue family to which Citrus belongs.) There are normal and natural and not a sign of disease.

Regarding the chlorosis in your key lime, did the yellowing set in over winter? Some citrus, particularly grapefruit in my experience, will tend to go a bit yellow in cold weather and then green back up again in spring. Also, is the yellowing on older leaves or does it show up when the leaves are just expanding? Chlorosis from iron deficiency (and similar looking zinc deficiency) typically appears on young leaves first.

Iron or other micronutrient deficiency is a real possibility; the frequent watering that bonsai receive may leach micronutrients from the planting mix. Also, if you have a high pH soil mix or water, that will exacerbate the problem. But I might wait to see if the yellowing clears up on its own with warmer weather – that is the pattern on a number of my Citrus (although I do not have a key lime.)

Best of luck with the lime!
David Brunner

Thank you all for your valuable input....David: the yellowing and dark green venation has been occurring on younger leaves as well....I should have talked about how the tree is sited....here in Zone 6 I summer the tree out of doors from about mid-May through the middle of October....for the rest of the year it is sited in my garage under fluorescents with my other tropicals - temp. averages between 65-70 degrees during the winter months.

Sounds like some chelated iron may help....

Thanks again.

Best regards,
Tom

Magnesium deficiency came to my mind first... adding Magnesium sulfate (Epsom salts) at a dilution of 8 tablespoons per 1.5 gallons of water may be helpful. As David stated, soil pH will also affect micronutrient availability.

Adding Iron or epsom salts may help. Make sure that you are just not treating symptoms. As John stated ph can be a root cause no pun intended with chlorosis. People spray leaves, dump minerals on soil etc but often never solve the real issue.

Cotton seed or rapeseed cakes will work. I dumped Iron, sprayed iron etc to no avail...once I scratched a little cottonseed meal into the soil 2 weeks and the tree was green as could be. Cotton seed will supply a little nitrogen, encourage beneficial micros and add some ph that will make the iron available to the roots for absorption.