Lemon Pictured below is a 2 year old plant grown from a pip at home and then transferred to my polytunnel this spring

If it's happy there, and it certainly looks happy, i'd leave it alone. Obviously keep it frost free and maybe pot it on next spring using citrus compost.

Watch out for pests, most citrus attract red spider mite, mealy bug and scale insects....as well as a few more probably.

Well done you, mine always die after the first year through neglect !!!!!

A lot of citrus plants are killed off during the winter months because modern centrally heated houses are very dry.

They need lots of humidity, so when you move it indoors for the winter stand the pot on an over-sized saucer filled with gravel. Keep the gravel wet to provide humidity and spray the leaves every other day with tepid rain water.

Be careful not to over water it. Water freely then wait until the soil is almost dry before you water it again.

When you put it outside again next summer, pot it on with fresh compost, give it a good watering and feed it with a high nitrogen fertiliser such as liquid lawn food. Water freely throughout the summer and keep it in a bright sunny position.

It probably won't flower or fruit, but you might be lucky. I've heard that Mayer Lemons tend to have more success of fruiting when grown from seed. It could take anything up to about 10 years for it to fruit, but even if it doesn't they make great houseplants and outside feature plants.

Crush one of the leaves and smell it. You can use the leaves in cooking, as a garnish, or to add as a decoration in a Gin and Tonic, etc.

Thank you for taking the time to answer, Myron that's great detailed information thanks again, but could it survive where it is in an unheated polytunnel?
As I've grown it from seed I would hate to loose it but I've grown two, one of which is the one pictured and the other one I've kept indoors at home throughout but that is very small indeed. They were however identical until decided to relocate the one to the tunnel.
Thanks, John

I would not chance them in a polytunnel over winter. Lemon trees are tender plants and need to be kept above 10°C. At a minimum temperature of 5°C they might survive for short periods, but this is for well established trees so young plants will not survive this lower temperature.

I grow lots of citrus trees from seed to use as rootstock for grafting. Unless you have the luxury of a heated greenhouse, ideally with humidity control, and can afford the expense of heating it, then the next best thing is to keep it indoors in a sunny position during the winter.

Fortunately, I have a large south-facing 25 X 10 foot conservatory where I keep mine over the winter. It's not heated, but it's well insulated, gets lots of sunlight and the temperature never drops below 10°C..

If you haven't got a conservatory then I would keep it indoors somewhere that gets lots of sunlight like a south-facing window sill, and ideally not over a radiator.

Your lemon tree that has been kept in the polytunnel is bigger because it has received more sunlight than the one in your house. This just proves how important it is to give them as much sunlight as possible. As an example, I have two identical cherry trees that were planted at the same time. One in my front (north facing) garden, the other in the back garden that faces south. The circumference of the trunk of the one in my back garden is about three times bigger than the one in the front

Hope this helps? Please let me know how it gets on.

Myron.

Thanks Myron, I really appreciate that. I'll bring it home as soon as possible. At the moment it has 2 branches coming from the main one close to the soil level, should I leave these alone or take them off of the main trunk?

It's a matter of personal preference. You could take them off now, or leave them and decide at a later date when it's grown a bit more as to how you want to prune it.

Thanks M, really appreciate your time

John