Perhaps this is also a colder than normal year in your area. If you only get a really cold year (temps in the teens or below) once in a while, you may be willing to cover two or three trees on the coldest nights and include some kind of heat source such as light bulbs. I personally wouldn't want to do that often but even here in SE Texas where we seldom drop into the low 20s, I still have to cover my younger trees several times most winters. Others here further north than I am have fantastic trees with fruit they grow indoors under full-spectrum lighting during their long winters. My two hardiest citrus trees, judging from their condition now after two periods we had this winter down into the mid-teens, are the Satsuma oranges and Meiwa kumquats. They still have nice green leaves and were not covered....but they are mature trees with 5" diameter trunks. Others here may be able to give you suggestions for growing potted citrus and other cold-tolerant citrus. Have you considered growing cherries, peaches and plums? :>)

Thanks. Yeah, it’s colder than usual, but not unusual, if that makes any sense. Every year there is mid-serious damage to my trees in that garden.

Lol, yes, I just made a video about my peach and cherry\plum trees. They grow well, but due to the humidity etc. require extensive amounts of pesticides etc. So far, citrus and kiwis are the only thing I grow that require no pesticides or protection from animals. I also like citrus because I can skip watering without the plants dying.

better setup is needed

A typhoon would destroy the lower setup. The top one may work if it was weighed down with concrete. What’s the top portion made of?

I agree that the top one would hold up much better in a typhoon. do you get typhoons when these hard frosts hit. The top can be made out of lass or wood. The posts would be concreted in place and you could wrap in bubble wrap. The setup in the lower picture would be place outside when cold hits. The top could be the same and the sides bubble wrapped.

Steve

PS I'll trade you our Washinton D.C's Baphoon for any of your Typhoons

One more bad thing about my inground garden: I’ve had moles for the last couple of years and they’re completely out of control now. A lot of my plants seem to be shrinking from the root damage. I’ve been using scissor traps continually for a year, lots of triggers, and haven’t caught one yet. I noticed they’ve even been active this winter.

Well I did an accurate comparison last night of the temperatures, and it supports my experiences. There is consistently about a 6°C spread between the garden and my house during the night. My house is also about 2° warmer than the local weather station. I have a suspicion the area around my house is more reluctant to drop below freezing in general. It’s also very difficult to shield from the stronger wind at the garden.

Last nights lows: garden -5.5; weather station -2; house +0.2.

Yikes that’s bad luck nice guy, in 9b you should be able to grow in ground. My old zone was 8b and people grew some varieties in ground. A greenhouse would be a perfect solution, is there a reason you can’t get one?

I think I am more of a 9A zone, but can’t figure out how to change the display on this site. We are up in the mountains a bit, so tend to get more extreme weather.

Unheated green houses are popular here from what I can tell for various inground crops. I think people use them more as cold frames. They are steel pipes with plastic sheeting over top. They need to be set up/ down properly though, as we get typhoons here. I am still trying to figure out how I could use one correctly for citrus. I suppose a few trees could be planted very close together in the garden and a greenhouse built over top. However, I can’t drive up to the garden every day, and there’s no power there to run automated windows or anything like that.

The area of our house that has direct sun is the front, and there’s only about a meter wide before it hits the street. Additionally, my wife doesn’t want anything junky looking in the front as we run a business there.

I was reading up on some information like this:

http://www.gardena.com/ie/garden-life/garden-magazine/everything-you-have-always-wanted-to-know-about-citrus-trees-and-overwintering-them/

I have a couple of possible areas around my house to overwinter citrus. One new area is vacant garage with a full southern exposure. I was thinking I could replace the steel rolldown door with poly carbonate? Maybe something like option B in that link above.?

Cold-hardy Yuzu inground:

I wouldn't bother. Instead I would invest in a greenhouse or keep them in pots...If you buy anything grafted, the scion might survive and the grafted portion would die anyways..What's the point? If it's that much work save yourself the agony and plant them safe and sound. The weather is changing everywhere and almost nothing is safe in ground anymore unless you live in the tropics or just above that.

Mike

Thanks. To be fair, this was the worst tree, and it had been planted just at the end of the season. The rest of the trees look like they’ve survived, although most of the leaves are dead.

I know inground is possible To actually thrive and get decent crops for some of the tougher citrus here, but I’m noticinging it’s always in a micro climate.

How exactly does the unheated greenhouse with citrus in pots work? Or for that matter inground citrus?

Typhoon season is usually September to November. The trees will only really need protection December to February.

You might need to go with the more cold hardy citrus. Perhaps you can go to a specialist nursery that carries the more traditional (but today uncommon) Japanese varieties. Kunenbo (translates as "nine-year-mother"), Keraji, Kinkoji, to name a few. Duncan grapefruit would not be a bad choice either. (That's a classic variety that can survive cold freezes in Florida) (That's a classic variety that can survive cold freezes in Florida, and I believe there's one originally grown from seed that's managing to hang on in a protected corner in the Chelsea Physics garden in London)

Of course kabosu and yuzu are extremely cold hardy, and natsudaidai is also.

Yes, thanks. Most of my trees are on the hardier end. My goal is fruit. The main problem I’m facing is that while very few of my trees actually die, they’re knocked back so much from leaf loss etc. during the winter, that they have little resources to put into fruit. I have had some good results, but it’s taking longer than it should to get there, and all my trees in that frost pocket garden feel like they’re on a knife edge. One slip up or a cold snap like we had this year, and years of work are gone.

I just started last season experimenting with some new trees in pots, and the results are promising. However, it sounds like the end result will never be as good as an inground tree.

So here I am.

Am I correct in assuming any kind of unheated non-electrically assisted greenhouse will only offer minor improvements? This will stop direct Frost, certain amount of wind chill, and retain some heat for limited time from the ground, but it will not save trees from consistently low temperatures? The main advantage will come from finding a suitable microclimate?

I am fairly certain some of my hardier variety trees ( I believe I wrote extensively about this elsewhere: certain Mikan, Kabosu, sudachi, shikwasa, Yuzu, etc) will do OK around my house with little winter protection. But if I’m going to take that step in the pots, I would like to see how far I can push the envelope to improve yields, as well as include some of the less hardy varieties.

I too am in this for quality/quantity fruit production will little labor.

Steve

Theniceguy..

Does it snow there? Does the ground itself ever freeze on the top or even deeper?

Do you get many nights with below freezing temps and are the nights very long like ours?

Like over 12 hours of darkness?

Mike

Hi Mike

Yes, it snows many times every winter, anytime between end of December and early February, although it usually only sticks around on the ground for a day or two before it melts.

The ground does freeze, and get hard and crunchy, but I don’t believe it goes very deep or lasts very long.

I’m not sure how to find out how many nights are below freezing, but I know many of them are during this time frame. However, it rarely goes very low. My garden hit a 40 year low with -10° temperatures two nights in a row.

I think the nights follow a typical seasonal cycle. Today we had 11 hours and 22 minutes of daylight, it’s getting longer for the summer now.

I assume that an unheated greenhouse will be of limited value, because I need to vent it to maintain a moderate temperature and avoid shocking the plant with sunny day greenhouse effect high temperatures, and freezing night cool downs? I’m really sure how or if people use unheated greenhouses to store winter citrus?

One option I’m looking at is a covered deck area around the back of my house. It’s surrounded by concrete on all sides and protected from the wind, giving it the highest outdoor nighttime temperatures on the property. I think the lowest it got was -4 a couple of times briefly. It also stays cool during warmer sunny days, a kind of buffer effect. It pretty much gets only indirect sunlight. So I’m wondering if this would be the best bet for a “hibernation “place for my citrus trees during the worst three months?

Theniceguy....Hey, seriously, I don't think you can grow anything citrus in the ground as you wish, just like me. It seems you have too much cold, especially with the ground freezing up. That is a sign that you can not grow something sub tropical at all. The only way you could is to find a tree that likes to go completely dormant, I mean a tree that does not need sun at all, burlap it or wrap it up with insulation from top to bottom. You would have to mulch in the root zone with at least 8 inches of mulch to protect the roots then cover the top to stop it from dying back.

If I was as determined as you to grow in ground, I would buy a good sturdy greenhouse one that can withstand wind and put in in the sunniest spot you have. Get an auto vent for it and a little space heater. It seems your winters are not as bad as mine, but bad enough...If you think about getting a greenhouse, even a small one like say 6x6 feet, you might fall in love with it and plant your best tree in ground.

winter of 16/17 I used a green house made of low E double glass sealed windows. It held onto heat longer through the night and didn't burn my plants under bright sun warm days. even with out heat it offer between 3C-6C degrees over the outside air. It also blocked sublimation freeze damage giving another 2C jump in protection. This year I have a Fukushu kumquat tree in a Low-E enclosure..

I’m not sure how to measure the extent of “ground freeze”, but it’s probably not as bad as you’re thinking. We do get frost, but I don’t think we have to deal with for example things like frost heave on ground posts.

It’s not uncommon to see large Mandarin trees near houses full of fruit exposed with little or no protection in the winter. A very famous citrus growing area is a couple of hours drive away, on the coast.

To add to the topic of man-made passive shelters/ greenhouses, I was told that citrus basically shut down when the root temperature drops below 15°C. So a fancy passive greenhouse that’s not kept artificially heated all winter will have no greater effect and just hibernating the tree? If that’s the case, there’s much easier and cheaper ways to do that.

Artificially heated and lit green houses sound like a money pit to me. If I understand correctly, you need to vent them regularly to avoid mold and other problems, which just means releasing your heated air continually. Very poorly insulated as well.

Well, heres the winter damage, took the covers off tonight:

https://www.youtube.com/watch?v=M6OVxivUsZY&feature=youtu.be

Hey, from all the videoas I would say it is definitely NOT worth it! It seems every year you will always have them recovering and go back to square one. I wonder how many times your trees can be stressed before they finally retire, roots and all...Plus, if they were ever to get huge, which I don't think they will if you have to keep cutting off dead growth, how will you protect them then?

I would grow them in pots since in your area, which I think you will get them out earlier than mine, you can have some real healthy very abundant trees with fruit without all the hassle... Nice videos by the way.. How long have you lived there?

How old are you? Are you old enough to start one from seed and try that before you even get fruit?

happy over the pond to you

4 post with insulated top and wrap bubble wrap around the post and you will get through these freezes.

Steve

Steve , actually that might work! Like mini greenhouses only taller....

Steve

Steve, I LOVE the bulb idea, even Christmas lights would create some heat, the old fashion ones right? Nice