where do you live? Container or in ground? Could be beginning of Mg or MN deficiency, which is made worse/more apparent by cold soil.

I live in NZ, so it is summer here, so cold shouldn't be an issue.

They are both in containers in 511 mix. I fertilise with citrus granular food every 2/3 months and foliage pro (what I have left) every 2 weeks.

Cheers,

Ben

The very tip of the leaf in the first photo seems to be dying, it may be salt build up. Do you periodically flush your containers with non-fertilizer water to get rid of excess salt residue from the fertilizer?

Yeah I flush the mix before fertilising again and sometimes mid-week without fertilising afterwards.

I'm not sure then, how strong a dose of Foliage Pro have you been using?

I use 2 tsp in 5 litres on a fortnightly basis

Not magnesium deficiency. That shows as a yellowing leaf with green veins.

Ok so that's some thing like 2 tsp in 1.3 gallons once every two weeks, I'd recommend switching to 1 tsp in 1 gallon (3.78 litres) weekly. So it'll be a lower concentration but more regularly, and will still add up to the same amount of foliage pro every 2 weeks.

Check your pH of the water....Try using vinegar since it will cause no harm and release the nutrients that are quite likely held up in the soil......I'll bet you once you start using vinegar, within a couple of weeks your leaves will green up! You should have NO nutrient issues with the fertilizer you are using unless the temps are too cool or hot as John says or the pH of the fertilizer solution is off....Are you using the hose a lot? Are you using rain water?

No need to flush your mix if you are using the 5.1.1 mix..You should have no issues with the color of your leaves with the fertilizer and amount you are using)

I am using tap water, which may be the issue. I use vinegar on my Blueberries, so maybe I will start doing that on my citrus too.

Will update after a couple of weeks.

Thanks for your help everyone!

quick question, how much vinegar per gallon when watering?

I have one tree that looks like this too and I think it may be fert burn? I think I was using too strong a FP dose.

Vinegar? I'm surprised. How much & how often to give my 2 froot tall Meyer? They cut all off but what was tied to little stick, I can't trim anything , so all I can do is wait for it to grow green & flower. Now I have nothing on it to trim. What can I do to get it to bloom & put out leaves or branches? It's warm in here since I got it 3 mo. Ago?

Thanks mike, I think I burned it when it was in its old mix, I just repotted to gritty. But good point on the ph, I have been meaning to get a tester. No time like the present!