Thanks for that info fruitnut!;-)

I too have my trees in a very cold room, dependant just on the sunlight from both my windows and skylights..The room gets down to the 40's at night, and 60's by day..The soil temp in one of my containers registered at 46 degrees..Ouch

I too have not lost a leaf yet, except for once...Excited..

That one day, I added some overhead supplimental lighting along with the sun, and a couple of them started to losse their leaves almost immediately...lol. So off the lights are, and my trees are just fine, dependant on the sun only. Saving myself some electricity too.

If I should decide to push growth by raising the room and soil temps to their growth comfort zones, my trees will be looking for much more light and fertilizer, and that is when I will add it.....

Mike...;-)

Your root temp. is very low, this will cause "WLD" or (Winter leaf drop). I suggest keeping you container citrus root temp. above a 72F to 82F.

plant54: This is why we were talking about soil temperature. As stated above, I've never had winter leaf drop either on potted or in-ground trees in my greenhouse. This is their 5th yr under these conditions and never one problem. I don't know why you think you need such high temperatures but citrus can be grown at my temperatures at least for a short period. By short I mean 40-60 days. That's what I've done.

Something about your system is out of balance: light, humidity, fertility...? In California I grew citrus outdoors with winter soil temperature in the 40s, no problem. Commercial growers do it every year. Your system is the one out of balance.

The Fruitnut

plant54: Fruitnuts point has been proven in my case also..

Your root temp. is very high, this will cause "WLD" or (Winter leaf drop) if you are only dependant on the amount of sunlight such as I get this time of year, less than 5 hours...

Therefore unless I plan on providing more than 9 hours of sunlight with lamps, I must keep the roots this cool to prevent "WLD", and so should anyone else growing citrus up here in our cold, very short days.

Not one leaf lost for the frist winter ever, and lots of blossoms on green trees...

So far sucessful...:-)

Mike..

Great topic guys. I dont know what my root temps are but now Im curiuos. I have citrus in ground and in pots. The in pot ones are in an unheated greenhouse and the ones in ground rarely get any protection at all. I am always trying to find the best ways to overwinter my trees and this info is helpful.

Scape

I put my greenhouse back on warm today after 46 days of chilling the stone fruit. Soil in the potted citrus shot up to upper 50s as air temperature hit the 80s. So for the next three months or so the greenhouse will be low/mid 80s on sunny days and 30s by night. I'm guessing the soil will mostly be in the 50s during this period. No wilting or adverse effects were apparent today as the air temp briefly hit 87F after all those days between 33 and 60F.

I'll report later how long the trees take to get back a good color. Not that they look bad now. Just a little yellower than mid summer.

The Fruitnut

I have mine outside in 26" italian clay and the temps are low 30's to hi 20's. All are bearing fruit or leaves and look just fine. Daytime hi's are 50-65. I have no idea what the temp of the soil is.

Fruitnut,

Do you find that alot of your trees bloom more tha grow when this happens?

I am glad our trees are hanging on, until the sun rises higher in the sy...:-)

Take care

Mike...:-)

I also was going to question that statement of requiring such high "72 to 82 F" soil temps in winter. Does not sound right .. unless of course Mike's last question is to plant54's point: is he *trying* to stimulate a winter flush or bloom? In which case I doubt only raising soil temps will accomplish this absent other stimulus (light, ambient temps, fert, etc).

I'm curious to hear more on this topic....

My last question was for fruitnut. I was wondering if he has many more blooms at such cool temps, because I certainly do...

The only way to stimulate a winter flush, sometimes bloom, depending on the variety, is buy highering the temps as plant54 suggests, AND, highering the amount of light levels..

But with high light levels, high temps, and a high amount of new flush growth, comes a high amount of "pests" indoors in winter, especially mites, unlees you are a lucky one...:-)

I suppose if conditions like this cause either a hot and dry atmosphere, or a humid and warm atmosphere in the middle of winter, I too would be a happy pest, partying my life away in these conditions while I eat all the fesh produce..

I was considering this again as I moved my containers back to their warm locations on the south side of the house (I had moved them into my patio for protection from our first freeze that came very quickly after warm weather). As I was carrying them up onto their rack, the sun shone very hot on my face. The southern side of my house runs about 11 degrees hotter than my patio on sunny days in winter (much hotter in summer as heat collects on the surroundings). The top rack is even hotter because it is never shaded, whereas all other southern racks are 50%-100% shaded during daylight in winter (neighboring house is two story). However, at night and during completely shady days the southern side doesn't offer more than a few degrees of warmth.

Your post about warm greenhouse day and low night temps got me thinking about my soil and foliage temps. Branches that do not have time to harden-off in cooler weather before freeze conditions hit suffer damage. The first night of the freeze, the trees on my top rack became exposed due to wind knocking off my covers and therefore suffered freeze damage -- and most were young mandarins!

My questions are this:
1) Was having the more cold sensitive younger trees in the warmest location counter-productive when fall ended? I assume they had the least amount of chill-hours to harden off before our sudden freeze.

2) Now that it's winter, should I be returning them to the same warm spot? The day time high temps in that spot are like 80 degrees but the lows are almost as low as the shady spots (high 30s). Fifty degrees seems like a wide fluctuation every 12 hours.

Ideally, I'd like soil temps to be above 70 (as the above poster had commented on) since for now I know the top racks are getting at least 6 hours per day of great light. I'm not interested in foliage growth as much as root growth (since some containers were only bare-root potted as early as two months ago). But I'd hate for this goal to cause further damage when severe temps hit again.

As I was looking at your pics and thinking about your temps, I was trying to come up with an imagitive way to keep the roots from getting so cold at night..

Those extremes are going to kill your plants..They will get so stressed out in those containers, they will react sooner than you think..In ground is a whole different story..

Maybe you could find heat matts, and place your pots on them if you keep them outdoors.

How about a plastic covering with a small heat source for night temps on a timer?

I am sure someone here could give an idea on how to keep your plants warmer at night. Personally with so litle of pots you have there, I would bring them in at night, and put out at day..Great exercise and your plants would appreciate it..Heck, I was hauling more than that indoors everynight this fall. It is worth the work to keep them happy..

Young or old, no matter how you look at it,they are all cold sensitive at those extremely colder temps..

If your lucky you may not loose them, but I wouldn't take that chance with mine..You might even see blossoms, but don't be decieved into thinking they bloomed because they are healthy...

Mike...

Mike, thanks for replying.

I've been growing container-only citrus in that exact location for 4 years now and have never lost any trees. It's relatively easy to grow in mild winters here (to see my weather you can look here: weather underground kfat). I only move containers when it gets to it's lowest -- normally around 30 for a day or two but this year it hit 23 already. I'm much too lazy to move them every night! lol You have quite a commitment there to your plants, I'm sure I couldn't grow citrus in your zone.

When I read Fruitnuts post I thought "my temps (not humidity) are near the same as your greenhouse when the heater is on".

This is the first time I've ELEVATED the trees so the top shelf gets all the sunlight during the day. The difference in *external* container temps with the "normal tree location" is over 15 degrees (due to radiant heat)! Ambient temps are not as much; I really need to track soil temps and bring that back to this thread.

Btw: In my previous post, it's a 40 degree fluctuation not 50.

cebury: That temperature fluctuation isn't going to hurt your trees. It doesn't hurt mine, and if I read your post correctly, hasn't hurt yours in four yrs. I don't know why people freak out about cool temperatures and citrus. I thought Mike had learned that cool is OK. Maybe I'm misinterpreting what he is saying. The roots will grow when you need them, when it warms up.

The Fruitnut

Hi fruitnut..:-)

My offerings were based on what cedbury posted here..To quote him...

"The first night of the FREEZE, the trees on my top rack became exposed due to wind knocking off my covers and therefore "SUFFERED FREEZE DAMAGE"..."

"The day time high temps in that spot are like 80 degrees but the lows are almost as low as the shady spots (high 30s). "Fifty degrees seems like a wide fluctuation every"

"But I'd hate for this goal to cause FURTHER damage when
severe temps hit again."

So I would say, freezing temps and COLD is not for the well being of his plants..COOL is..Even down into the high 30's without such a high jump of temps in such a short time.

In fact, cedbury came here asking for help based on two stories, now as we can see. On the last post it was said that they always did well in these conditions, and that confused me.. Maybe I misinterpeted what was said, and you did not..:-) Notice I did not respond to his last post..;-)

That is why I only gave suggestions based on what he asked in his post prior to the last. The next one had a different tune...All in all, I just shared what I would do if it were me, and wish him the best of luck..

Personally,

I would never expose my trees to such extreme temps, whether they can take it or not. I would not risk their health and subject them to cruel conditions..Heck if I were a tree, I would not be happy...There must be a reason nurseries try to keep their temps in there as stable as possible, unless the fuel costs forces then to provide less heat in my area.. My local nuseries lost plenty of their citrus due to a couple of nights when the power went out and drove their temps down to the low 30's just in one night, just to hit the 80's that same day...

Not cool, but COLD and FREEZE..were brought up there..

If his plants survive the 50 degree flucuations, thats great. Mine never have, not here, not even a 30 degree one..I see them wilt and respond badly. How much they can take, I do not know. I guess everyones trees react differently...

How are you by the way..Are the temps there finally warming? You must be excited about the sun finally starting to rise higher in the sky as I am...:-)

Mike..:-)

Mike: My trees are now subjected to a 50F temperature swing nearly every day. Low most nights is 33F. That's what my heater is set on. Days are running about 84F as high. They haven't started growing yet as I've been two weeks at the higher daytime temperature. Soil in the pots drops into 30s at night and 60s late afternoon. In ground soil temperature is low 50s at 4 inches.

I'm just relating what works for me and what is found outdoors in good citrus areas. Don't have all the answers. But do think it is possible to kill citrus with kindness. Soil temp in the 70s and 80s in winter, as recommended by some, are never found outdoors in winter anywhere in the USA. 40s, 50s and maybe some 60s are outdoor winter soil temperatures. We're not being cruel to our plants if that's what we provide.

The Fruitnut

Fruitnut:

That is why I said everyone's trees react differently...No set rules. Our conditions, light, amount of sun, cultural apllications, and practices, can be totally different from ours, which affect each of our citrus greatly.
Many ideas are put here for the taking for members to enjoy, and then applied in a way that works for them and their growing needs..

There are some concrete ways of growing citrus which is a different story...
But the temp thing has always been debatable for sure.. I tend to side with you on the cool side for winter. This you and dave taught me, and I thank you for it.

I am not diasgreeing with you, but to the contrary. In fact many times, I agree on many points you make and acknowledge that, and I even ask you questions that seem to go unnoticed by you at times..But that's ok.....

As you have done, I was just relating what works for me and my feelings about "my" plants and how I view this type of treatment..People here are going to do whatever they want to do, based on what we say or not. That is why I wished him goodluck..

But,

I don't understand this idea about killing plants with kindness philosophy though? I killed them with a lack of being in tuned with their needs, reactions to the enviroment, no concerns for pests and proper fertilizer, and from neglecting them in the past..:-).

Take careand have a great day fruitnut..:-)

Mike: My kindness comment related to the idea that maybe some people keep their plants too warm in winter, particularly the roots. Sure 70s or 80s sound like something citrus would like. But maybe they don't need it or maybe it's not even best.

I think we need balanced systems. Light, soil temperature, leaf temperature, fertility, water, etc, etc, should be in balance.

But one thing I need to keep in mind is that some people have different objectives than I do. Some are more into growing citrus as an ornamental. They want to see growth all year long. I like my plants to look nice. But fruit production is my main objective. So I tend to mimic field conditions. Since I once grew citrus outdoors in California, that's my primary focus.

Sometimes this forum is a little slow. I may not add a lot of wisdom but maybe a little "color".

The Fruitnut

Just musing out loud....
In my experience, I've found the phrase Killing with kindness to usually mean "overwatering."
I'm not saying this is what Fruitnut meant....or what Mike was doing previously...merely exploring the possible answers.
It's no wonder, of course. Most potting soils are so water-retentive that one really can't help but "overwater."

I instructed a friend not to water a (Jade) plant until the leaves began to feel soft - then, not five minutes later, he drenched the plant right in front of me. Moral of the story: Some people can't be trusted with advice, no matter how simple. Not even written directions. They're simply too stupid, too meddling, for their own good...or for the good of their plants.

Josh

Fruitnut,

Don't under-estimate your self..You add much "wisdom", flavor and color. It it weren't for members like you, it would be an even slower forum..

I appreciate it for sure, all the morsels you bring here.

Have a great week and enjoy your holidays..

Your's truly

Me..:-)

The term 'killing with kindness' applies to lots of things besides plants, when you think about it.

Plants are often over watered or given little sips every day. They are also given fertilizer or other elixirs as if they were tonics or vitamins or medicine!

Some people might be 'stupid or meddling' (Josh's words), but I believe that most are simply ignorant. It takes, after all, a bit of effort to educate oneself about good plant care techniques, and not everyone is willing to do that.

Balance is definately needed..:-)

Have a merry one Rhizzo..

"Ignorant" doesn't go far enough to describe a person who waters a succulent less than five minutes after being told - with rationale - why not to water. Ignorant doesn't know better.

Stupid knows better, but does anyway. ;)

Josh

Mike,

Back to my situation -- I've been monitoring the ambient temps and most sunny days are indeed 40+F variation swings between day and night times -- without any problems to my mature and young trees whatsoever. This is normal for southern full-exposed gardens in my area, where citrus trees are in practically everyone's backyard. It's only when temps are below 30 that we start having issues.

Both you and Fruitnut very slightly misunderstood a statement, which proves I was especially unclear in this point:

The particular location I'm referring to (pictured with the rack) is one of my normal WINTER growing spots -- but usually the trees are on the ground.

This year I've done something NEW: I put that rack in place with citrus on the top shelf (ie. elevated). The "elevated" trees are now getting direct sunlight therefore ambient temps are about 15 degrees higher than the bottom rack and about 20+ degrees than shady ground locations 10 feet away. Many days during winter we still have sun here but on cloudy and rainy days there is no significant difference in temps between the top rack, the bottom rack, or the shaded spots.

They've done fine in the past and would've done fine this year had my frost cover not blown off once in the night. We've had 4 more 30F nights since the first and the trees have shown no further decline in that location when the blankets are in place.

Does this make more sense? I think I can rephrase my entire questions (in a new post) and exclude my rambling details for clarity.

As always, thanks for replying.

On a separate note, I've noticed the gritty mix media temps are quite a bit lower than standard MG soil mixes. Fruitnut when you are tracking your soil temps, are they all gritty mix?

They will be fine then..Seems like you already know what to do..:-)

My trees are not comfortable with the temp flucuations so often and much. Mine reacted very badly, in the spring and summer, even with a 20 degree one..Just mine I guess..
In house, even worst..

Take care

Killing with Kindness more examples...

Hey Guys,
Maybe I can clear up a little of the soil temp fog. A few
years back there was a forum I got on thru the Ultimate
Citrus Page. There were several Europeans that grew citrus
in "glass houses". It was sometimes difficult for them
to control temps. They claimed the trifoliate rootstock
went dormant about 55deg F if I remember correctly. I
didnt note all the details but they seemed to think the trees trying to grow and the roots trying to stay dormantcaused some terrible imbalance with leaf drop and maybe worse. It may also becycling in spring contributing to this too.

I dont have a greenhouse so I just forgot about it till
now. I may put some young or backup potted plants in
the garage or a spare room for a freeze. When I do
it for more than 36 hours they have leaf drop. I think
its the lighting since my garage is not heated and not
extremely dry. The plants will be about the same temps
as in the yard before the freeze.

The "glass house" problem may be something different.

I heard it takes 500 degree-hours below 50 F to fully
harden mainstream citrus to take the mid twentys
It seems about right in my expieriences.

Tangelo x tangerine hybrids work for me.

Larry

Great job Larry....

This is why my grafted lemon meyers can not handle alot of sunlight when the roots temps are too cold here in New England. Neither can my other citrus...The only one that seems to be able to handle such cold temps and lots of sunlight plus artificial light is my kumquats..

This is the reason why I say cold temps,just sun, and no extra lighting..

Warm temps more sun is needed, or artificial lighting...

This has worked wonders for me...In fact, when my heat was being fixed on Christmass eve, I had ONE day when the temps in that room rose above 70, and most leaves started to cup, curl, even within high humid conditions....

Till yesterday, I have had a few leaves lost on my lemon meyer and my orange trees...Now that the temps are cooler again for the past few days, they seem ok, and the leaf loss seems to be subsiding drastically..I mean temps below the 60's, 50's by night

OK -- it's spring now, following those low root temps, and I think you've hit some warm spells in Tx like I have in CA Fruitnut. So what happened to your trees that where the root temps were low? Dessication from the winter cold spells?

Mike,
Reading this post, I just checked my Oro Blanco soil temp. It registers at 63 degrees. Today is so gloomy. I am wondering if I should put it under lights but the problem is if I do, that room is the warmest in the house. Would I end up hurting it more by just keeping it there for a few days? I know that in a few more days it should be able to go back out. I am hoping that this cold spell doesn't last long.
Andrew

Hi Andrew.

I wouldn't even bother bringing it in...
Mine is still outside and it is 48 degrees and doing fine..It is resting and will start up again once the temps warm up. It is there to stay as every year, unless the temps dip below the 40's, then in a pop up greenhouse it goes to keep warm at night...:-)

I stored my tree at temps in the 50's all winter with just natural sunlight...It will get alot more light outdoors than inside, even if it is warmer inside..I would just leave it and let it toughen up with the elements outdoors. In and out no good for mine unless needed, like extra cold temps outside.

Moving in and out may do more harm than good..

Mike..:-)

Mike,

We were discussing root temps, fluctuations, etc last winter. Well I did experience some decline when the coldest temps hit and I could not get the containers protected in time. You had warned me about extreme fluctuations, I'm not sure how much it contributed but it's very possible was a significant factor. Most trees were fine, very little foliage loss, but after looking at the roots on two of them there was definitely root loss. Three other trees (not on the rack) whose canopy were covered VERY well but the container (roots) were exposed, and their roots filled the entire container (i.e. the smallest container sizes) suffered the most.

As is typical with winter frost damage, the trees looked cold injured (like Fruitnut described above) but overall looked just fine. It wasn't until warm temps arrive that you know -- first dessication then decline. These trees had the most root loss: roots pulled apart like thin strings, fell off when shaken, and washed away extremely easily. The trees started budding immediately, and are doing fine now, so I know they'll live. But it certainly set them back.

I protect a good portion of my containers (via double potting) and they all did perfect. But some weren't protected and our last winter cold spells came quickly and were extreme. I'll be better prepared next time.

You make some great points cebury! How have you been anyways? Goos to see you here..:-)

One thing that I have learned myself, I will never let my plants, especially citrus weather outside when I know temps are going to go below the 40's at night.

Add to that the fact because my mix drains so fast and well, as Andrews does, the coller temps will have no adverse effect except maybe a bit of a nutrient uptake with a bit of yellowing leaf problem, until the temps warm up again..

So far so good with mine each year outside unless temps dip below the 40's...At day time, temps are usually in the 50's and 60's, and warmer by now.

You have certainly learned alot and showed us something to think about.

Good to see you again!

Mike..:-)

Hello Guys,
Cebury, Your information is much appreciated. I think some of you guys here should get together and right a handbook on citrus trees. I could never name all the people here that have helped me but my citrus appreciate it greatly!
Hi Mike,
Well the snow has returned(Hopefully just a quick cold zap and thats it!) and I moved all the citrus in plus my Nebel's Gold plumeria. Moving that Meyer in is such a back breaker! The weather changed so fast on us last night. My buddy went to bed before I realized that the Meyer was needing to come to in. I had to lift that huge pot and move it in by myself. I am very fortunate that I didn't repot it yet but I know that the mix in the pot right now has broken down somewhat and will be heavier than the mix I am going to replace it with. I am not worried about the roots rotting yet but it will need to be done within a month. Anyhow, I put the Oro in my living room. This is cooler than having it in my bedroom under lights but I am thinking I really need to put it under the lights. I have seen a bunch of new growth and I worry that it will abort and I don't want to loose it. If I put it under lights, it can get 12 hours of light and the soil temps should not go above 65 degrees. Will that be acceptable for the Oro Blanco? I really want it to start growing. I worry about loding all that growth and most of it came out a few days after I fed it the FP. You have a pop up green house to Mike right? If the outdoor temps are in the low to mid 30's, and in full sun, it should be easy to enough to keep it at 40 right? I am really considering getting one of these after I get my HID light setups. I would think I could extend the growing period outside to at least the beginning of December depending how the weather goes. I should also be able to put them outdoors around March. Most of the time, March is pretty warm. We have had sporadic freezing nights here and there since the first week of March. I know it would be a lot easier for me to control the temperatures in a pop up. None of my base board heaters have a control on them to adjust the heat and my room is always 10 degrees warmer. Well I just hope that this cold ends by next week. I have one plumeria that is going to be blooming, and they much prefer to be outdoors!
Andrew

My citrus, both potted and in-ground, are about done blooming and look great. There was very minor leaf loss after warmup. I'd say less than one percent. They are about done with the annual leaf shedding which comes later and is minor.

My potted Washington navel still has some yellow leaves from vigorous growth last fall. But even that vigorous growth has flowered heavily. I'm going to have a big crop on everything.

I'm finishing the last of 2009 crop fruit on Washington. It has been fabulous!