Overwintering citrus without a greenhouse

[itsthegardeninglady]

Hi, I'm working with a group who have got two new citrus trees about 5' high in pots in a yard. We've not got a greenhouse or a conservatory to overwinter them in, and I wondered if anyone had advice about overwintering them outside. Under bubblewrap perhaps?
Cheers!

[Alison]

Bubble wrap isn't goid for plants as they will sweat. To be honest, I'd be quite anxious about leaving them outside, we lost one in an insulated greenhouse once. They do sound rather big but would it be impossible to bring them inside during the coldest months? Not sure how much light you can provide in your house though.

[rhonsal]

I have a lemon and a lime tree and overwinter them in my garage - it gets some light during the day through the window in the door and is just warm enough to keep them healthy!
If we get a bad winter they may not survive outside.

[starloc]

What sort of volume are the pots? and what varieties/rootstocks? , it can make a very big difference to temperatures, also how old they are, thickness of trunk etc


I used to keep some outside in the UK, you need to keep the frost cloth off them or they burn like the second picture in this other thread
http://www.growfruitandveg.co.uk/gra...-uk_31091.html


They would be best inside, in indirect light, unheated room with a window open....
greenhouse is better,

In strong light, they need warm roots, put them on a pet bed heater or the leaves will fall off

Outside , I often used to keep mine outside in Liverpool , frost cloth, light bulb, fairylights ( bulb tyoe not the led ones ) due to size of them some weight 400kg ,

in a cellar is also ok or a garage works as its dark and cold so no light needed

Outside, You need to keep the roots dry as they need very low water in the winter, the roots need to be protected from freezing solid, dry compost helps, water freezes and crushes the roots, also causes root rot

If you need to keep them outside then they would need a minimum of a framework of some bars of wood made into frame, covered with polythene or frost cloth, no leaves or branches touching, make them draft proof and tie them down!
Polythene lets light in so would need shading to prevent leaf loss, frost cloth lets rain through and gives way in snow
You need to wrap the pots in lots of bubble wrap and take them off the floor to let the roots breathe
Do this and they will be OK to about -5C or -10C for short periods, long periods there will be some damage to green bits of stems and leaves
If you add a 240w 100W old fashioned filament light bulb with no shade, hanging near the center of the tree it will be fine, I also add fairy lights to keep it all warmer
Fairy lights stay on October to May, 100w bulb if its cold

I have mine in the back bedroom in Bulgaria as the greenhouse is not finished yet and I have just returned to the UK for a month , but the large calamondin was too heavy, its outside in the snow this week...... -5C very unusual for this time of year, under the roof of the open fronted barn in a place it gets the sun, it will be ok.....probably..... being a calamondin

I am planning on putting polyethylene on this frame from a Costco garage made of 2 inch steel tube , inside something like this they would be fine , this is the best/easiest way for outside



In eastern Europe/Russia it is now usual to grow them in the floor and build a plastic frame for the winter, but if in pots the usual way seems to be in a hole in the floor like a motor mechanics pit and put plastic on a frame over the top , often with a lightbulb for heat in very cold weather

Some people use clear corrugated plastic roof and hand cloths around the edges

[itsthegardeninglady]

Cheers - lots of info!
To fill things out a bit, the trees are not at a house, it's a day centre where the central heating is going to be on all winter and there's no option of a cool room with light and the window open. I'm wondering if we can get a lean-to plastic greenhouse which will fit the two trees...