yellowing lemon leaves - help please

[cornish crabber]

I have a small lemon tree in my conservatory - a limonella. It has been growing well and has set fruit. However its leaves have started to go yellow and some have dropped off.
I have been feeding it regularly with a droplet feeder.
Any idea what's wrong?

[cornish crabber]

I have found out what the problem is. The poor thing is covered with red spider mite! Couldn't see them myself - they are tiny! Have sprayed with SB plant invigorator and will keep it misted when it's hot in future.

[sarraceniac]

Hot CC? What is this hot you have in Cornwall? Is that what we had in 2006?

[cornish crabber]

Five weeks from the end of May through June were very hot and very dry down here - then it all went cold wet and windy Are we ever going to get a 'normal' summer

[starloc]

Be careull with the drop feeder, they need to dry out betwen watering/feeding or the roots can rot, its not ood to use a drop feeder or similar on a citrus plant

[cornish crabber]

The drop feeder I'm using is made by Growing Success and specific for citrus trees. Surely that should be OK? It only holds about 30ml and I use one a fortnight as per instuctions for a 15 cm pot

[starloc]

I heve never used them but the `experts` on the citrus growing forums ( many have tried them ) all say never to touch them as the constant moisture will kill a citrus plant , citrus come from areas with poor soils that dry out quickly, areas that flood with heavy rains every now and then and then dry out for months, they need very high levels of nutrition as well and the brands i have looked at have completely incorrect levels of nutriets for any citrus tree , even though labled as a citrus feed

[cornish crabber]

That's interesting, Starloc. I have probably been overwatering , though the pot does dry out very quickly in the conservatory. How do you provide your citrus with nutrients?

[starloc]

i feed at every watering, mix the feed/water and lower the pot into water and soak for a few minutes, then take it out, let it drain, then do the same again with the bucket of citrus feed/water , check the type of citrus feed is a good blend such as global orange groves, chempak or `the citrus center` one ,

I also mist/spray them every week with citrus fertiliser, and around the time they look like they are going to flower i spray every week with a mix of 1 teaspoon of pottasium nitrate per litre of water in with the citrus feed, this increases the level of flowers and the level of them that set fruit, every month or so when watering i add a teaspoon of epsom salts to the bucket of water ( adds magnesium ) citrus need magnesium and no fertilisers seem to contain enough ( if any ) in the blend of micronutrients

If you are in an area with low calcium in the water ( i am ) then you need to add a bit of calcium nitrate to the fertiliser , every few months, or a tiny bit to the fertilsier you use every week

( only ever water it if its dry , dont just water because it needs feeding, if the water is still there the feed will be )

[cornish crabber]

Thanks for the detailed advice, Starloc. I'll try to follow your routine.
Things have improved a bit since I cleared the red spider mite infestation and gave it some Epsom salts - new growth looks good. Here's hoping.