43* is not too cold for citrus. That is warmer than your refrigerator. When the weather people forecast lower than 40*, I know to bring them in.

Also to mention, I don't believe the "kunenbo" in the UCR citrus collection is the same delicious kunenbo that can be found in historical botanical collections in Japan. I've seen pictures and descriptions, and they don't match up.

Rare hybrid ([CiTemple "edible" citrange x Ichang papeda] x Minneola tangelo)

"Arctic Frost" (hybrid between Satsuma, perhaps 'Xie Shan' x Changsha mandarin)

Most of the top died, since it didn't like the early Spring cold temperatures, and it regrew from two spots in the bottom branch.

Tiny Keraji seeding planted in the ground, just to see what would happen.

It was planted out in mid-March, completely defoliated, some minor stem die-back, but it has since releafed out.

The Yuzu is putting out some new growth late into the season.

Covering keraji seedlings in ground with cut transparent water containers, as part of an experiment to see if they will be able to survive

I theorize that the plastic covers will help increase the inside temperature by 3 degrees at night, maybe more than that if factoring in wind chill.

socalnolympia - As part of your experiment, you might want to consider getting a small wifi temperature sensor and sticking it under the dome so that it can broadcast the temps to a small console that you would have inside the house. This would allow you to get an idea of the temps within that cover. The "wind chill" temp is not something that makes any difference to plants since they respond to absolute temperature ("wind chill" and "heat index" and "real feel" or equivalent terms are more a "people" thing), although "wind" itself can obviously be desiccating to plants if they are exposed to it and it is persistent enough. What might make a difference in temperatures at night is radiational cooling, with heat in the ground being lost to the air on nights with no wind. The dome should help to mitigate that effect.

I must say that your pushing the envelope that most people would die to do and be successful. I'm glad your trees make it every year. What are the average lows there? Do you ever get to beloe 0? Consistenly below 32 for months? I wish I could grow a very cold tolerant citrus by just covering it with insolution and leaves but I still can't think of one tree that even could survive that. I wish there was one.

Mike

Well, I thought the lowest it typically dips down to is 15 degrees, but I did a check of the weather records for recent past years and actually for the great majority of those years the lowest temperatures seem to be in the low 20s.

The climate zone maps show the location in zone 8a. Usually get a very light snow here, but I know just a little bit further out going into the sound they may not get any snow fall at all.

Nice Job Socal Be careful not to cook your small trees.

My latest New Zealand lemonade on Seville sour. Bud starts growing mid august 2018

New Zealand lemonade on Seville sour orange · More Info

The graft

New Zealand lemonade on Seville sour orange · More Info

Other side

New Zealand lemonade on Seville sour orange · More Info

Steve

The little keraji seedling has actually put on some noticable growth since being covered with the plastic container. Here it was at the end of August, not having been covered yet:

Here's the transparent plastic container that was put over it:

Here it is on September 20, temporarily with the cover off so you can have a clear view:

Notice that obvious new leaf growth in the back. I'm not sure if the container helps maintain humidity and it is benefiting from that, or whether the container is acting as a little greenhouse in the earlier part of the day, helping to raise the temperatures a little bit. It's Fall now and the temperatures are beginning to cool off. It's still plenty warm in the middle of the day but the mornings can still be pretty cool/cold. (Since the first part of the Fall season is still dry, that means big temperature fluctuations between night and day) So I've definitely noticed that covering with the container has already helped. (The Pacific Northwest has a cooler climate in the Spring and Fall, so this strategy would be particularly helpful here)

I've also done the same for another keraji seedling, somewhat bigger in size, but I just planted it in the ground a week ago so it's too early to see if it's helping.

I will say this though, at this time temperatures are beginning to cool off and several of the seedlings left outside are beginning to turn yellow because of the cooler temperatures, yet I see no sign of that yet on this seedling, even though it's planted in a cooler spot that's only getting early day sun right now (and not even that, since often the mornings are completely overcast). The container covering seems to be fighting off the cooling temperatures, at least for now.

Just to point out the obvious, keraji probably has the ability to be much more tolerant to cool temperatures than other common citrus (so there is a reason I am doing these experiments with less common varieties like yuzu and keraji). I realize it's still a small seedling and still vulnerable to cold temperatures, but I've read a large mature keraji can supposedly survive down to as low as 12° F.

Keraji is also related to Satsuma. (DNA marker analysis done in Japan showed its origins were consistent with a triple backcross of kunenbo with shikuwasa)

I plan to plant some blue Meconopsis poppies, just to contrast the difference between the citrus and the flowers, since blue Meconopsis only grows in cool Himalayan-like temperatures. (I read one person comment that while they grew great in Scotland they seemed to be too difficult to grow in Southern England, just to give you an idea of the cool temperatures they like)

The citrus will thrive during the warm half of the year, and the blue poppies will thrive during the cooler colder part of the year, so either way one of them will be bursting into growth.

Showing a picture of the blue poppies growing next to an in-ground citrus tree will be a great way to show it is far outside of citrus growing territory.

It's a blue color flower a lot of gardeners wish they could plant but they don't have the cool temperatures for it.

Admittingly the location here has more Summer heat than Seattle, but the Summers are still as short as they are in Seattle. Possibly better for growing citrus but not Meconopsis. Well actually there are just a few days in the Summer here that get so hot I think citrus can struggle a little bit and get baked in the hot dry sun. All the more important to keep the citrus well watered since those hot warm temperatures conducive for growing will not last long.

Sort of funny, the warmer half of the year is just the opposite of the cooler half of the year. The warmer half has pretty extreme hot temperatures that don't last long, while the cooler half of the year only has mildly cold temperatures but they don't let up and are constantly cold in duration.

Definitely some big differences here from trying to grow citrus in parts of the South. I think most years the absolute lows are higher, but the long cool to cold temperatures means the growing season is short (especially the growing season for trying to grow citrus).

I hope these aren't too many thoughts and overanalysis. Maybe some people don't have the patience or time to read all this.

Definitely some big differences here from trying to grow citrus in parts of the South.

I think it's that Pacific coast thing - "rainy season" ("rainy" being theoretical because I do know there has been more and more drought there than normal) from fall --> spring vs on the Atlantic coast (notably citrus areas like FL), where it is the reverse, with the "rainy season" being spring --> fall. The Pacific coast gets their biggest wildfires in the summer "dry season" and the Atlantic coast gets their biggest wildfires (not mentioned as much but they are significant) during the winter "dry season".

Al, there are always people that try to stick it to you. Got the same happen to me like all the time, same people, they think they are top guru,s. They are good in spitting garbage.

A moderator told me long time ago, after I told him that I don,t have much to offer, he told me, just tell us what you are doing. Up till this day that is all I am doing. I don,t need this forum for what I get out of it, if I get 1/10 out of it it is a lot. I got some friends here which I like a lot, those are the ones I focus on.

flying dragon

love the experiments

I have started on my greenhouse about 6 months too late for safe completion befor first frost. I am working very hard to get it done intime

West wall with 6 foot ladder for comparison

Looking north east through west wall.

Lower wall has 2 low-E windows with a 3/4 inch air gap between them for a total of 4 sheets of glass and 3 dead air spaces.

Upper section has 1 of the 2 double glass low-E windows installed. This wall is the most difficult to build and will be permanent 24-7-365.25

Steve

Steve - are you just going to have your in-grounds there or will you be adding your potted ones too (although you probably could sink the pots)?

Steve can you come to my place and set up something like that for me? I’ll even pay your airfare and food. Great job buddy

Jenny I have not decided yet on potted plant placement. I have 2 more enclosures to make and if I can get those done I would like to plant 3 more outside with enclosures

Mike My time is shot this year. If you are serious I could plan a vacation with my wife in your area and I could lend a hand. I believe you already have a green house. and an unheated enclosed patio. Anything you do GH wise would be more expensive than using lights in your sun-room even i you use enough light to provide heat.

Steve

Thanks Steve! I remember last year you had individual enclosures for at least one tree so it will be interesting to see your final setup. I know it's hard trying to operate in between the crazy weather too.

Keeping an eye on your roots

Seville sour orange seedling recouping after failed graft

Steve

Wait Steve, who is that little seedling guy next to the big one? :-D

Seed grown North star sour cherry. It came up where I planted it in my Dieffenbachia.

I have 2 Seville cuttings rooting along with 50 Meiwa seeds in the pot. Nothing has come up yet. The oldest seeds are 2 months old and the newest about 1 day ago.

Awww... One of my sisters has a Northstar in her backyard (it was planted by the previous owner) and it has stayed "dwarf" - not more than about 10 - 12ft tall and a good fruiter. Only thing is, the blue jays often get the cherries as soon as they ripen and the weather is always wacky at that time, so I rarely get chance to get over there to grab a bag of them before they are gone. Pitting them is a PITA too but they taste really good in pies. lol