What's wrong with my lemon tree?

Those shoots at the base are good. Prune it back by about half the height in spring to encourage it to bush out. It also looks like it could do with a feed with a citrus-plant food and also a bigger pot with some John Innes no 2 soil based compost. Then pinch out any shoots that get too long. Stand it outside in June, but remember to harden it off, as with any plant going outside, or the leaves may scorch. I think you're doing really well with it!

Try bonsaitreeforums.com in the citrus section you will find help on potting mixes, pruning, root pruning, feeding, light requirements and watering. Whereas you might not be growing a bonsai per-se, you are growing a tree in a pot.
I hope this is of assistance.

Hi

I have just purchased a lemon tree and an orange tree, can i grow these in a large container outside as i only have a patio.

I am new to gardening so any advise would be helpful,

Thanks

Oranges and lemons are only suitable for pot culture in UK. They can be put outside from about the end of May til end of September. They need to be indoors for the rest of the year as they are not frost hardy and will be dead by the next spring. Sorry. Water with rainwater whenever possible and use a citrus food as advised on the packet. Make the pot as large as is suitable for the size of the plant.