Refrigerator Dormancy

[fourteener]

Friend or family with a house

I understand the problem with the apartment. I would find a family member or a friend who has a home. If they have landscaping on the north side of the house. I would just did a hole and put the pot down in it with some mulch over it and let it be outside during the winter.

The ground will keep any cold snaps from harming your tree. The north side of the house is out of the sun which will allow it more time to come to life with a smooth transition, rather than being on the south or west side of the house that heats up early and kicks your tree into growth mode before you want it to.

 

[GarlR]

[FOOTNOTE][/FOOTNOTE]

Just realize that you're looking at a substantial amount of time before this is bonsai worthy since you're not able to put it in the ground for a while.

I know it will take a long time before it is of any worth, but that is exactly the reason I wanted it. I wanted to get it young so in 20 years if it is still alive, it will be extremely gratifying.

@fourteener - I don't have any family that lives near me. I do not have any friends that I trust with any of my trees, even if they did live close to me. (Plus all live in apartments except 1)

@Austin - Yes, I said that my apartment complex has juliet balconies, just not on the first floor nor in my 1st floor apartment.

 

[Austin]

ah ha so I mistook your statement about moving to a new more exspensive apartmen with a bacony, as you all ready having the apartment with the balcony

 

[GarlR]

ah ha so I mistook your statement about moving to a new more exspensive apartmen with a bacony, as you all ready having the apartment with the balcony

Stop trolling.

 

[Anthony]

Yes, Garl,

[ GarlR - wrote - I know it will take a long time before it is of any worth, but that is exactly the reason I wanted it. I wanted to get it young so in 20 years if it is still alive, it will be extremely gratifying. ]




that is extremely gratifying -------- from seed or cutting or sapling, most forget that 20 years down the road, even with very slowed growth, you can still have taper where needed and effects of age.

Plus it does make eyes widen when someone asks from what stage you trained it, how long it took, and that time meant nothing.
Good Day.
Anthony

 

[Beng]

I tried this many years ago when I moved from the east coast to the west coast. I had a beautiful japanese larch back then. I bought a large ice box just to overwinter it as it wouldn't get a strong enough cold snap in the southern california area. Over the period of about a month decreased the temperature to 30 degrees and initiated its dormancy. Kept it there for 2.5 months, during the last half a month I raised the temp steadily to 50 degrees, the temperature control was done using a digital beer thermometer accurate to 1 degree. Brought it out in early spring and exposed it to the fresh california air. It leafed out and I thought it was doing great but then it died in the summer, I'm not sure why exactly. It could have been due to the difference in California's dry air compared to NY's humid air. It could have been due to overwintering in the fridge, it could have been due to the root ball drying out much faster then usual as it was still in my east coast soil mix. I do think you can do this type of overwintering though, however a fridge without a temperature control varies quite a bit in a 24 hour period, and a freezer has a freeze/thaw swing. If you want to do it again get a beer control like this http://www.amazon.com/Johnson-Contr...2881&sr=8-1&keywords=beer+temperature+control you put the probe in the fridge and plug your fridge into this and then this into the wall. You can maintain an extremely tight temp range. Just remember to maintain a reasonable relative humidity inside as well.

Glad i'm back where we have a real winter again.

Replying to my own post.... Thinking about this more, in practice there is no reason this technique should not work. In fact i'm thinking of buying a big garage fridge for an experiment.. The tree I lost last time was a larch and I would bet chances are I let it dry out too much as I wasn't very experienced with watering back then. If the tree gets ample water and is kept dormant for 3-4 months each year it should work indefinitely. ESP if the tree is allowed to go dormant on it's own outdoors during the fall/early winter prior to being put in the fridge. If you can rig up 2 temperature controls and a timer like I mentioned above you can even create a slow constant weather swing like most places have between Nov-March. In addition you could create daytime and nightime temps, If I decide to try this on a tree in progress I will post pics.

 

[rockm]

The problem with larch outside their range isn't really winter cold, but summer heat. They don't like hot roots...

 

[0soyoung]

The problem with larch outside their range isn't really winter cold, but summer heat. They don't like hot roots...

What soil temperatures do larch like?

 

[rockm]

I have no real idea of exact numbers, but I'd say if your summer temps range into the high 90s, with sustained nighttime temps above 75 or so, they're iffy.

Each one that I've tried to grow here in N. Va. (and I've tried American and Japanese larch) has ultimately died. Summer temperatures here can range into the low 100s, but the daytime temps don't seem to be the problem. Nighttime temps can range into the 80's for months.

Being that larch are northern species, not accustomed to such high temps and high humidity, they decline and die in more southern locations. They don't die all at once, but are gradually worn out over a few years.

I can't grow them, but only 50 miles north of here in Maryland and Southern New Jersey and Pennsylvania, they thrive... Go figure.

 

[0soyoung]

I have no real idea of exact numbers, but I'd say if your summer temps range into the high 90s, with sustained nighttime temps above 75 or so, they're iffy.

Each one that I've tried to grow here in N. Va. (and I've tried American and Japanese larch) has ultimately died. Summer temperatures here can range into the low 100s, but the daytime temps don't seem to be the problem. Nighttime temps can range into the 80's for months.

Being that larch are northern species, not accustomed to such high temps and high humidity, they decline and die in more southern locations. They don't die all at once, but are gradually worn out over a few years.

I can't grow them, but only 50 miles north of here in Maryland and Southern New Jersey and Pennsylvania, they thrive... Go figure.

It is really too bad that you never stuck a meat thermometer probe into the pot to see what the soil temperature in fact was. Soil/root temperatures can be very different in pots than in the ground and there are lots things one can do to lower the higher temperatures that often occur in pots.

 

[rockm]

Simply can't grow them in the heat, talk to anyone south of the Mason Dixon. Larch just don't work down here, precautions included.

Anything that has that much hassle is, well, a hassle and not really worth the trouble. There are other species that are just as interesting that do well in this area without having to resort to thermometers and other extra effort.

 

[miker]

I just came across this thread and wanted to contribute my experience with providing winter dormancy for temperate trees in the refrigerator for the past 11 years. In my experience, for deciduous trees, it absolutely works beautifully. The refrigerator (assuming the settings keep the temperature between 32F-40F) actually provides the perfect environment for trees to accumulate needed chill hours without freezing or warm spells that could cause early initiation of growth. Deciduous trees need no light when leafless, so there is no problem there whatsoever. It is important for trees to be watered (as in any other situation) when the substrate starts to dry, and I find that I need to water each dormant tree once every 2 weeks or so.

I just put my new trident maple in the refrigerator, where it will remain for another month to ensure it gets plenty of chill hours so it can be "rested" and vigorous this spring. There are growers keeping trident maples in Central FL, but to me, the new growth (and the leaves, twigs and branches) tends to look weak and "strung out" compared to specimens I see that are grown in temperate regions that actually have a winter. This species is doable here in Orlando without the fridge technique, I would just prefer to give the tree proper dormancy and gain the healthy growth that results. To me keeping 5-7 small trees in the refrigerator is not too much of a hassle, since it enables me to grow a few trees here that would either flat out not succeed here or lack the fortitude of their up-north counterparts.

A note about transitioning to dormancy. In experiments, I have successfully coaxed fall foliage and leaf drop by keeping a tree in the fridge at night and in a sunny window during the day. While this certainly works, it is obviously not practical as it is time consuming. Thus, once a tree has had its full growing season, I carefully defoliate it and set it in the refrigerator for a set amount of time.

As far as conifers go, I have not had much success utilizing this technique. I grow a lot of unusual exotic plants and I have been keeping an Ephedra sinica plant (evergreen temperate desert plant) happy for 6 years by keeping it in the refrigerator for 3 months and putting it outside on a cooler, sunny day about every 3 weeks to give it a little light. This has worked for it. Trees such as fir, spruce and pine have failed in the past. I currently have a small spruce (rescued from a nursery here in Orlando last summer, a long way from home for this tree!) and a collected hemlock from PA that I am attempting the refrigerator technique on. I put these outside in the sun for a few hours each week, and so far they look healthy. Once they are finished being refrigerated and are put out this spring, I will really know whether they have been successfully kept or not.

There is nothing magic or counterintuitive about this technique, it is just keeping dormant deciduous trees in a cold, dark environment that effectively simulates the conditions in which trees achieve dormancy in winter. Kind of like the opposite of a greenhouse, which is a specific space that simulates a favorable climate for the types of plants kept within.

 

[just.wing.it]

This is all very interesting. Thanks for sharing.

 

[miker]

No problem just.wing.it. I just want it to be known that this is a viable solution for those who live in regions where winters are too mild to successful keep some/many/all temperate tree species. I have read of others who use refrigeration to provide bonsai with proper dormancy in California, can't remember where and when I read this.

Ideally (if money was not an issue) I would have a large walk-in fridge in which a whole collection could be kept for the winter.

One final point to mention...I have even been successful with trees such as sugar maple (Acer saccharum) and Japanese maple (Acer palmatum "seigen"), which tolerate the heat just fine in the summer (and grow well, just like similar trees I have observed up north) here as long as they get the proper amount of dormancy. The heat does not kill these trees, though often the leaves are a bit "worn out" by September. This interesting experimental result is the product of an artificial "environment" that does not and likely could not exist in nature. That is, there are no locations (that I am aware of at least) that would both provide a tree with 3-5 months of consistently cold (almost always below 45F) temperatures and 6-7 months of summer with highs 85F +.

Just for the heck of it, here is a photo of my new trident maple spending the final month of winter in the fridge so it will be fully ready for spring growth. It may not need it this year (since it was just sent from much further north), but it can't hurt. Note, that tree (stump) in front of the trident in the blue pot is my Acer palmatum "Seigen" that has just been cut back to a stump, since the nebari is decent but the rest was nothing but reverse taper.

 

[Anthony]

Miker,

what we do with junipers is just set the fridge to vegetable crisper cold and leave for two months.
Seems to improve their response.
Mind you these are experiments, as we don't train junipers.

I understand why the trident we had was lost now.
Thanks for the look.
One day we will try Acers again.
Good Day
Anthony

 

[miker]

Anthony,

I am sure I can get conifers, such as junipers to achieve dormancy in the refrigerator, it is perhaps just more complicated, since evergreens need a bit of light, even when dormant. I have read conflicting reports about this though. It may very well be that, below a certain temperature (likely some temperature below freezing) even conifers do not need light.

I will have to try what you suggested. I am also eager to see what happens with my hemlock and spruce. The reason I am optimistic so far is, in previous experiments, the spruce I was working with (several including Norway, Black Hills and Red Spruce) already showed signs of decline at this stage whereas the two conifers mentioned above still look perfectly healthy. My Ephedra sinica (Ma Huang) is basically a foot tall evergreen bush I sprouted from seed in Feb. 2010 and has now spent 6 full winter seasons in the fridge.

Fortunately, my Juniper is a "procumbens nana" that does perfectly in Central FL without a need for artificially provided dormancy. You might try this variety Anthony without the fridge, since it clearly has little need for chill hours. Also, FL red maple would be a good variety of Acer rubrum for you to try, since it has a very low chill hour requirement.

In summation, with my experience using this method on conifers so far, I am virtually certain I could make it work if I had the walk-in refrigerator and then installed adequate lighting for the conifers as well. As I lack the resources for this kind of setup, I will have to wait until I select the correct Powerball numbers, then I will get back to everyone.

What I will start doing is documenting my success in such a way that in a few years I can prove that this method works and for which species. I will also carefully document how I (usually in November) simply defoliate a tree, then put it in the refrigerator, without needing to worry about gradually inducing dormancy or anything like that. In my experience, it is all the same to the trees. For a dormant deciduous tree in a pot, 36F is 36F and it makes no difference as far as accumulating chill hours is concerned whether the tree is in a manmade "cold box" or outside under the bench.

Don't forget to keep trees in the fridge watered sufficiently. As with the experiences above, I have lost trees to drying out in the fridge. This might be the largest pitfall to this practice since it can be easy to forget to water in this situation at times. I have also lost trees to drying out outside, so this is simply a basic care issue.

Sorry about the upside down photo above, I kept trying to edit and could not seem to correct this.

 

[AJL]

Hi everyone!
I may be stating the obvious here but many commercial tree and shrub nurseries in here in UK routinely use cold storage- ie walk in refrigerators, mainly for bare root nursery stock- it enables them to lift trees from the ground in autumn and store them until ready for despatch to planting sites and customers in spring.It can help extend the planting season which is useful eg for big landscape projects where weather and ground conditions delay the start of planting.
If it works for them on a commercial scale why all the debate!!! just ask your local nurseryman lol....
Obviously provenance is a factor in determining which trees require long or short dormancy, but in bonsai circles with so much trading, mixing and moving of plants between regions it is very difficult to be sure of the true origins of your plants and hence their daylength and chill hours needs etc.
I for one would struggle to fit any of my trees in the fridge. I just heel them in for the winter or leave them unwrapped against a sheltered wall!!
This winter our temperatures have barely dropped below minus 5C so no problems with my trees . My Larch are already budding and I haven't had time to start wiring yet -

 

[Anthony]

Miker,

could you put in the area where you live in the Location section of your avatar box ------ it would help your case.

Here's the odd one Mike, on my side as November approaches, all of the hackberrys and the ginkgo, their leaves
turn yellow and fall.
By Christmas everyone is leafless. We don't have to defoliate. Always assumed that the shorter days caused the
effect.
Then the trees are placed in a North side, out of the wind and allowed to stay colder for placement in the fridge around
the last week of January.

The process has become so automatic, no thought is given to doing it.

We did lose one of the original hackberrys, through drying out, in the fridge, but a main root shot back up and the tree
started over anew. Great huh.
Good Day
Anthony

 

[thegrower]

Only advantage to vernalizing in the fridge is if you are trying to produce your tree out of season. This will only work if you can also give it a false summer. I do this to a million plus hydrangeas a couple times a year. For the hobbyist I am not sure why you would want to do this.

 

[miker]

Thegrower, I do this to provide dormancy to my temperate trees that otherwise would not get enough chill outside where I live. This fridge treatment is just for one season and the trees do great outside the rest of the year.

I wouldn't consider it out of season, since the trees spend their time in the fridge during winter (normal time for dormancy in the Northern Hemisphere) then outside to grow normally with the rest of the seasons.