Yellowing leaves on citrus

[Rach23]

I have a question re lemon trees.

I bought this tree almost 2 years ago. For some reason, this year the tree has gone haywire and is constantly flowering and making lemons. I have been constantly pulling off the tiny little “lemon bulbs” so the tree can concentrate on growing the existing lemons on the tree.

You can see the leaves on half the tree is quite yellow (with green veins), which saw me add more fertiliser (and that I suspect send the tree into more flowering/lemon producing mode).

How do I fix the yellow/green leaf issue as I don’t think it’s fertiliser issue (pellet fertiliser for lemons I bought from Bunnings). Is it also a bad idea to throw the tiny lemonlets back into the pot (my thinking was, the tree spent the energy to create these things, throwing them back into the same soil, the tree can take the nutrients back??)

[MitchellMc]

Hi @Rach23,

Could you please let us know what the fertiliser was, how much you applied and when you applied it? It would also be helpful to know how often and for how long you water the plant, and how much direct sunlight it receives throughout the day.

I suspect it is a nitrogen or magnesium deficiency causing the veiny and blotchy looking leaves. However, after applying a complete fertiliser like Scotts Osmocote 500g Citrus & Fruit Controlled Release Fertiliser at the prescribed rate, I would expect to see some improvement after a few weeks.

I look forward to hearing more about your plant and providing a solution to your issue. 

Mitchell

[Rach23]

I bought this fertiliser - the words “premium fruit and citrus food” and “lasts 2 months” was the decider in getting this fertiliser (first time I tried growing lemons).

I shook maybe 2 handfuls out and spread  them around the outer ring on the pot earlier this week. It’s east facing atm so gets the afternoon sun until the sun sets so I would say good few hours. I guess I can move it further to the front where it will get all day sun but then it’s not as protected from the winds.  It gets watered every 3 days. It gets watered when the leaves of my chilli plant starts to droop. I usually count to 10 for each plant before moving to next pot in my watering.

Should I remove more tiny lemons so the tree isn’t expending so much energy?

 

[MitchellMc · Accepted solution]

@Rach23,

Black marvel is applied at 50 grams per square meter, so two handfuls, roughly 75 grams each, would be more than enough. In fact, if you can, I'd recommend tipping the pot upside down and removing some as that would be close to twelve times the amount needed. Three-quarters of a tablespoon would be sufficient. As you only applied it earlier this week, I wouldn't expect to see any improvement as yet. 

The amount of sun it is receiving, although not optimal, should be enough to keep the plant healthy. However, I would suggest you change your watering regime to once a week as a thorough soaking until the water runs out the bottom of the pot. Only water if when you stick your finger in the pot, the soil is dry.

The plant is producing fruit because it is able to, but you can remove the fruit if you wish, and that will store more energy. The production of fruit is not directly related to the yellowing of the leaves.

You could try some Yates 500ml Citrus Cure Zinc & Manganese Chelate at the prescribed rate on the packaging as the plant might be deficient in those elements.

Let me mention @Adam_W and @Noelle to see if they can offer their diagnosis.

Mitchell

[Noelle]

Hi @Rach23 

@MitchellMc has given you sound advice re the Black Magic and also the zinc and manganese chelate product from Yates. The yellowing of the leaves with green veins makes me think there may be a magnesium deficiency present. If the fertiliser and other treatments don't make any improvement to the tree's appearance, try good old-fashioned Epsom Salts (magnesium sulfate) at the rate of 1 dessertspoon dissolved in 9L (standard watering can) of water.

Citrus in pots need a couple of good soakings per week over the warmer months - water until excess drains out the base of the pot each time. Over the cooler months, do the finger test before watering - if the top of the mix is dry to the second knuckle, add water.

[Rach23]

Thanks @Noelle @MitchellMc for the advice!! Will keep an eye on it and if the fertiliser and the sun (I moved it to an all day sun spot), will try the chelate or epsom salt.

I have a question re watering which I suppose would apply to all pot plants? Your finger is only so long and most pots are deeper than your finger.

Few days ago (in preparation for winter), I pulled out my peony plants, added extra potting mix to the bottom of the pot and slid the peony back into its pot without disturbing its roots. I couldn’t help but notice, the top section of the soil is quite dry but the bottom of the pot is very wet. 
The finger test would tell me to water it but visually looking at the soil at the bottom would say no more water - but I can’t lift my plants out constantly to check!

I read about air pots and just had a crazy  idea, would it be a good idea to get a drill with the smallest drill part and drill a few holes around the sides (near the bottom) - extra air through the bottom to dry the soil and let out excess water?

Please let me know if it won’t work - been known to have a black thumb 😁

[Noelle]

Hi again @Rach23 

If the top of the mix is dry and the mix in the base of the pot very wet, then drainage is likely a problem.  Increase the size and number of drain holes in the base of the pot and stand the pot up off the ground on pot feet or a triangle of bricks or similar so the drainage holes are clear and will allow excess moisture to flow out readily. A few holes around the perimeter of the base could be helpful but should not be necessary if the base is above-ground.

The other issue may be that you need a layer of coarse material in the base of the pot to facilitate drainage - blue metal, broken up pieces of terracotta pots ('crocks') or similar to a depth of 50mm or more depending on the size of the pot.