! Cold hardy citrus trees

Make sure you keep the seeds moist. Citrus seeds aren't like apple or pear seeds. If they dry out, they will never germinate.
John S
PDX OR

I have grafted a Poncirus trifoliata to Seville sour orange to serve as an inter-stock since Meiwa kumquat can't be grafted onto sour orange

I won’t have any seed until I start harvesting the crop later this month.  The citrumelo cultivar is Dunston.  I have 2 foot high, 1 year old citrumelo and Yuzu seedlings, but I’m not set up for shipping plants.

this years greenhouses will provide shelter for my Fukushu kumquat for its 5 winter planted outside and in ground.  4th winter outside and in ground for my Nw Zealand lemonade on C35 rootstock.  3rd winter outside and in ground for my Valentine pomelo on US897 rootstock.  Last my Meiwa kumquat on kuharske citrange will see its 2 year outside and in ground.

For many years I have been trying to figure out how to make some kind of a greenhouse work.  I know my Meiwa kumquats would love it. I use plexiglass covers for some plants like Thyme and licorice, which don't like our wet, soggy winters and springs.  They die otherwise, from diseases. They like it dry in winter.  We don't get as much cold as in Cincinnati, but we're very wet for a very long time.  Partly I have to figure out where I would store the glass during the rest of the year when we don't need it.  I know that you can get some windows and things cheaply if you go on Craigslist or Restore, for example, but the logistics are important. Getting something together cheaply that can be stored easily is the trick.  Thanks for inspiring us to figure out how to do it.  

John S
PDX OR

I have a small greenhouse I made out of used windows I bought at Habitat for Humanity, it's kept my in ground Satsuma mandarin trees protected for about 7 years or more now.
The greenhouse stays up year-round but many of the windows can be removed or opened for summer use.  When I take them off I just put them beside or in the greenhouse.

So it seems that folks are worried about citrus trees in greenhouses?  This is my concern because I am hoping for a lemon tree in a big pot in the greenhouse I am building. Is supplemental heat the concern? or, is it cold ground that that is the issue?

I have an aquaponics setup that I am installing; I decided that I am going to enclose it with a greenhouse so I do not have to harvest all of the fish (Tilapia) before freezing temps each year.  I have considered heating the water with a solar flat plate or an evacuated tube solar collector and hoping that the ambient heat from the 300 gallons of water in the tank along with the water running through the grow beds and sediment collectors will be enough passively warm the greenhouse enough at night without any additional heat inputs.

Is there a minimum winter temp for citrus trees? Is there a minimum number of winter daylight hours needed for citrus (Lemon)?

This was an interesting thread to peruse.  Thanks

Mark
Frog Hollow Schoolmaster's Homestead
Myersville, Maryland

Mark, Lemon trees are the LEAST cold hardy of citrus trees, you'll need to keep it above 29F at the least.


I have Owari Satsuma mandarins in ground in my greenhouse, but they are hardy to around 22F, so there is wide variance between varieties of citrus.
(The only heat source is two incandescent light bulbs, one near each tree.  They are turned on by a greenhouse thermostat at around 35F.

Edit:  Some info on varieties of cold hardy citrus: https://www.gardeningknowhow.com/edible/fruits/citrus/cold-hardy-citrus-trees.htm

Meyer lemon and ishang lemon are more tolerant of cold than true lemons.

Due to predicted lows of 22 degrees F, I harvested all of my Yuzu crop and most of my citrumelo crop (left some fruit deep in the tree’s interior to be picked later).  Result; two wheelbarrow loads of citrumelos and a bucket each of Yuzu and citranges.  Used one of those long handled cut and hold pruners to pick the fruit, making harvesting fruit from the thorny tree a much less painful process than if I tried to hand pick the fruit.

If your citrus trees have fresh growth they need to stay frost free and above 32F and the fruit is destroyed below 28F.  My trees seem to do fine with 8 houres of daylight rain or shine.