Hey every one,

My citrus seems to have gotten through the winter pretty well. Although I think the temperature will probably have been a little to low.
It can go as low as -7°C in the hardest wintertime during the day and a bit colder during the night. On the other hand, the temperature can fluctuate from day to day very hard. One day it could be freezing, another day it could be +2°C.

I've let my citrus (sinensis) spent the winter in the garage. It has a thick window that lets in a bit of light. I don't think that it freezes inside (otherwise the sinensis would've long been gone), but I do believe the temperature goes very close to the freezingpoint.

Since I am planning on buying new citrusses, I am wondering if they will survive these temperature's considering that not all off them will be as tough as the sinensis.

Do you guys think I can keep all off them in the garage during these hard wintertimes or should I be looking for better ways? I've got a glass greenhouse, a plastif foil greenhouse and a gardenshed to my usage. Mostly the nights are the biggest problem I think.

I've been looking around and found systems like tranching, using heat systems,...

PS: I know its not even top summer but I would like to gain some information about what you guys think.

edit: how low can the temperature during the night go for citrus?

2nd edit: I've been thinking about good ways to get the citrus through the winter when I was was in bed (yes its true :d ), and I will have to use a greenhouse because otherwise, there won't ever be direct light on the plants. Or I could use lamps but that would be an investment so I'll cancel that idea because of the costs. The greenhouse it will be!

Especially the tranching keeps running through my head as a good option. Could it be usrfull building a tranched greenhouse inside the foilgreenhouse? Thats kindoff double insulation.

I live in the the mountain region of Georgia, USA. We have similar winter temperatures as you described.
I have been growing two Owari Satsuma mandarins in my yard for 2 years. They have done well and are undamaged.

My protection is a small greenhouse that is just big enough to cover the two trees that are less than 2 meters apart.
The North, West and East sides are made of stacked rock that is back filled with soil to absorb the Southern sun in the day. The North side of the greenhouse is a type of bubble-foil insulation instead of the plastic on the other sides.
When temperatures drop below freezing, a greenhouse thermostat inside turns on two 40 watt lights, one for each tree. The lights rarely switch on or stay on all night.

The lowest temperature I saw last winter here was 10F / -12C.

I have Trifoliate Oranges (Poncirus) planted in various places around the yard and they are completely unprotected and undamaged.

I just bought and planted a Citrangequat which reportedly will survive -12C when mature with little to no protection.

You mention trenching- I think this is a good idea, actually being that my greenhouse is rock and soil on 3 sides, its ALMOST in a trench. The first year I did not have the walls built up around the 3 sides and I remember that the heat lights came on much more and for longer times, so I think the insulation added by the soil and rock really made a big difference.

I like your idea about the greenhouse inside of a greenhouse, I think that would add a lot of insulation value.

Trenching it will be then considering the fact that the glass greenhouse is used during spring and summer by my dad so constructing insulation walls and removing them every year would be to hard.

The trench idea seems pretty cheap and effectiv. It does need a lot of good preparation though. Like which materials should be used as a first.

Someone else on this forum mentioned a couple of ideas I will be adopting this winter.

1) Heating a barrel or bucket of water inside the greenhouse with a 50w aquarium heater.

2) Use of those inexpensive metallic survival blankets to reflect light back on the trees & add some insulating warmth.

Anthony

Hi (Dag) Sven Limoen,

Forget any citrus but the Citrus Trifoliata. I tried several hybrids here in the polder in the Netherlands but they all died: Yuzu (died after two winters), Citrangequat Thomasville (died), H119 (citroncirus x paradisi): died and Citrange Morton (citroncirus), also died.
Like I said only Citrus Trifoliata survives in our climat.
If you live not to far away from Antwerp (en), in the botanical garden there is a huge Trifoliata tree, and if you ask the caretaker nicely, you can take some fruits home, sow them and nex year you have your own Citrus trees.

Yes trifoliata us survive the subzero temperatures if you're thinking of growing in the open air ... it is also good for us as a graft with citrumelo Swingle but needs a cooler wintering

By the way, does anybody know a Poncirus tree closer to my home (Dronten, the Neteherlands), because Antwerp is still two hours by car!

Swingle Citrumelo, Poncirus X Changsha, Flying dragon, Citrus Ichangensis and Poncirus X Ichangensis all survived here in copenhagen.
Lowest temp winter 10-11 was around -10 C. but nearly 3 month with temp below 0 C

Martin

You could look at The Dutch National Citrus Collection at the Loo Palace or
at The Dutch National Citrus Collection at Twickel.

- 7 ° C all citrus survive, you just should use a hardy sort.