Under and overwatering can show some of the same symptoms. Have you felt the soil to try and see if it feels wet? Did you get the tree and just put it in the pot? Was there any water at the bottom of the pot?

Or you can try something like the chopstick test to see if the soil is overwatered.

http://homeguides.sfgate.com/check-soil-moisture-chopstick-30981.html

The lemon tree is in the same pot that it was purchased in. The first time I watered it was after a week and it was slightly damp rather than wet (the normal point at when I'd water my other plants. Whenever I water plants, I generally water in the sink so that they don't sit in the excess water.

The soil definately isn't too wet anymore as it's now 3 weeks later and I have been checking that the soil is only very sightly moist before watering again.

But I don't know to get it to improve - it isn't getting worse though.

From the photos it looks very wet to me, but you may have just watered it beforehand. I killed my first Meyer years ago from over watering by treating it like my other house plants, I treat my current one more like a cactus and it's never been better. Depending on your environment it may need watered once a week or once a month, I let my soil feel dry to the touch when I stick my finger 2-3 inches into the soil, then water until it drains through the bottom, I usually water about 1 GAL for my 5 Gal trees but I have a pretty fast draining soil. I only water about once a month in the winter but my trees are in a cool/cold garage and use very little water at a time. The leaves on your tree are too far gone so your tree will drop those and make new ones (hopefully). Since your soil looks really water retentive I'd use Bacons tip of a chopstick into the soil close to the roots, if it comes out clean its good to water if it comes out with wet/damp soil then wait longer. It may be holding too much water near the root-ball and never fully drying out there even though it seems dryer in other parts of the soil. Hopefully this is the issue because to me its an easy one to correct once you get the hang of what works for your tree. Good luck!

Hi,

Thank you very much for your help.

The leaves have been like this for about 3 weeks and haven't dropped yet - would it help the plant if I pruned it or is it better to leave it?

Coral

I'd let it do its own thing with the leaves. It may take a few more weeks but hopefully you will start seeing new growth.