Author Topic: Anyone here really pushing the zones hard? (maybe even successfully?!)  (Read 1125 times)

naikii

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Hello hello all,

My name is Nate and I have a problem. I am totally addicted to purchasing subtropical fruit trees. I have about 20 different varieties from mangos to jaboticaba to anonas to garcinias.

In sunny Australia, the sun is slowly dipping, losing several minutes of sunlight even day, and what is worse approaching winter.

Where I live winters are harsh. By Australian standards it is as bad as we get. By US standards fairly mild for most of the continent, but horrible for subtropical plants, being squarely in a cold zone 9a.

Each year for most of winter we will sit at around -2 to -3 most nights of the week, with several -4 to -5o C days per month typically and one or two below -6. I believe -6 is around 20F.

All my precious little friends are in containers, under a single patio with open sides, and a clear perspex roof to the sky. This offers some protection from frost, but only takes the edge off the cold.

And so, being only 2 months into Autumn and with multiple nights already below -2o C, I need comfort and friends. Anyone here done this successfully?

Tell me your tales and whisper me your secrets.

shpaz

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I think it's better to make small heated green house if you can.

naikii

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I wish this were a possibility!

shpaz

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Since its a patio, what about trying to close off the slides a bit to stop strong cold winds partially then adding a small heater at night?



fruitnut1944

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+1 on the greenhouse. Anything covered but bright light with a heater is a greenhouse. Mine works wonders in a very harsh 7b climate.

Plantinyum

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I am also in zone 7 ,bunno a or b ....I grew  alot of tropical fruit plants without a greenhouse,that is cherimoya ,carambola ,dragonfruit ,passifloras ,guavas and so on. They were containerised till this year, since in fall I build a greenhouse and have planted most of my tenders in it in the ground, It will be heated in winter and I will be posting updates when the cold hits.
 I really think the gh is a game changer since this winter without heating the lowest temp there was -7 which is zone 9 I believe .

brian

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Yes, heated greenhouse is the way to go.  Next best is container growing and moving plants inside when it is too cold. 

K-Rimes

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I'm in 9b and growing a lot of 10a plants. No problem at all when you have even an unheated greenhouse that gets sun during the day. I saw 26f outside here this winter and the GH stayed around 39f with just a small heater running sporadically in the night.

Greenhouse greenhouse GREENHOUSE. Insulate it as best you can with the double wall panels and bury it a foot or two. Make it double as big as you think. I wish mine were bigger. It's 24x10

naikii

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No room for a greenhouse sadly :( The property is quite small and on a steep hill. I am moving after this year and will be erecting a more subtropical safe environment then for the ones I love best.

In the meantime I am currently purchasing some incandescent christmas lights to weave up and down the stems to hopefully provide a degree or two.

I expect that some/many of these plants will not get through the winter at all.

In the longer term, I am wanting to find out which of these plants will be able to tolerate my climate using microclimates and can tolerate the colder months with only a small amount of protection. Outside of my favourites, I do not want to have to baby 30-40 plants every winter too much and so want to build in a little bit of an idea of whether it is a total waste of time with even the best microclimate, or if there is some possibility of survival with a minimum of care.

I was considering things like heat mats under pots, and thinking of getting some clear plastic and stapling it to the beams and enclosing the whole patio, and other such treatments, but then thought about this prospect year after year and would rather some less power hungry and labour intensive method. I am happy to enclose and add incandescent Christmas tree lights to the stronger plants that could possibly be planted in ground one day for those winter months, but not 40 plants.

In some ways i think I would like to just satisfy my own curiousity as well. What will survive? What will die first? What will be the unexpected surprise? Will it be a total disaster? If I baby them through winter and 50% get through I will never know if they would have gotten through unassisted, and that will just keep me up at night!

K-Rimes

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No room for a greenhouse sadly :( The property is quite small and on a steep hill. I am moving after this year and will be erecting a more subtropical safe environment then for the ones I love best.

In the meantime I am currently purchasing some incandescent christmas lights to weave up and down the stems to hopefully provide a degree or two.

I expect that some/many of these plants will not get through the winter at all.

In the longer term, I am wanting to find out which of these plants will be able to tolerate my climate using microclimates and can tolerate the colder months with only a small amount of protection. Outside of my favourites, I do not want to have to baby 30-40 plants every winter too much and so want to build in a little bit of an idea of whether it is a total waste of time with even the best microclimate, or if there is some possibility of survival with a minimum of care.

I was considering things like heat mats under pots, and thinking of getting some clear plastic and stapling it to the beams and enclosing the whole patio, and other such treatments, but then thought about this prospect year after year and would rather some less power hungry and labour intensive method. I am happy to enclose and add incandescent Christmas tree lights to the stronger plants that could possibly be planted in ground one day for those winter months, but not 40 plants.

In some ways i think I would like to just satisfy my own curiousity as well. What will survive? What will die first? What will be the unexpected surprise? Will it be a total disaster? If I baby them through winter and 50% get through I will never know if they would have gotten through unassisted, and that will just keep me up at night!

I was much like you when I started out and had some successes my first year keeping things alive with frost cloth and incandescent "hipster" lights strung around through my dragonfruit and all the smaller stuff sprinkled in between in the enclosure. I started to get aggressive and buy things knowing they were edgy and maybe wouldn't make it but I was confident in my technique that worked the year before. I lost a lot of really nice plants two years ago and smartened up.

A lot of the time, even if they survive, they're never quite the same and die a slow death. I had a beauty of a grafted mango tree that survived three 9b winters but finally succumbed this last year and died to the union. I will not chase mangoes again.

This year I parked a bunch of plants that wouldn't fit inside the greenhouse (since it was so full) in my landlord's garage and they did awesome. I just put them in there for the 5 coldest days of the year and then pulled them out when the frost risk was gone. Totally paid off. They are firing up better than ever. If you have a big garage or storage shed, that could work too.

Anyway, I'm kind of rambling but the point I'm trying to make is be smart about it and you'll have more success and it'll cost you less money and stress. You won't see soursops, rollinias, mangoes, or mangosteens around my 9b zone for good reason.

brian

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Re: Anyone here really pushing the zones hard? (maybe even successfully?!)
« Reply #10 on: April 29, 2021, 08:13:05 PM »
I agree... if you are using containers and you can't keep them actively growing through the winter you might as well just store them dormant someplace like a basement or garage. 

naikii

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Quote
I was much like you when I started out and had some successes my first year keeping things alive with frost cloth and incandescent "hipster" lights strung around through my dragonfruit and all the smaller stuff sprinkled in between in the enclosure. I started to get aggressive and buy things knowing they were edgy and maybe wouldn't make it but I was confident in my technique that worked the year before. I lost a lot of really nice plants two years ago and smartened up.


It's funny, one of the stores I order a lot from says this in their description;

Quote
Use the item specifications above taking particular note of Climate and Frost Tolerance to make your decision. For some reason the personality of people who like to grow fruit trees favours the bold and people from VIC like to grow Subtropical - Tropical plants even though they are more suited to Temperate - Subtropical. This also works the other way people in QLD like to grow Temperate plants when they should be growing Suptropical - Tropical plants. There is nothing wrong with this but you must accept that you are taking a risk and you should research techniques that will minimise this risk.


I have to chuckle because it is so accurate. Your average gardnener heads down to their local nursery and buys a local plant that they know will perform well in their area.

Gardeners like us, who spend all their days on the internet researching new and interesting plants, who read through forums and blogs and who are always looking for the next possible thing are another breed. We are not satisfied with the average common varieties available at the big box store. Not satisified with the common fruits that grow easily in our regions. Not satisfied with a single cultivar. We feel the need to collect it all, and enjoy our hobby and push the limits to their max.

It is only when nature has punished our audacity and confidence by taking from us all our favourite plants, killed every stem to the ground and turned every leaf black that we either double down and invest more money and resources to try even harder, or resign ourselves to acceptance

One day I may learn that I cannot grow rollinias in a location that gets down to -7o C most years, or I will succeed, and until I am taught that lesson personally, or succeed, I will keep trying!

K-Rimes

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I killed a beautiful flowering Rollinia last year and its death will haunt me for the rest of my life, probably. For reference, it never hit freezing here and I bagged the tree with incandescent lights.

I applaud your enthusiasm, just don't go crazy blowing money on plants that simply will die a sad death.

There is zone pushing and then there is killing plants for sport.

CarolinaZone

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Yep, I'm in Zone 7a/b and I am doing in ground citrus. I am doing mangos and guava in an unheated greenhouse.

 

Plantinyum

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Yep, I'm in Zone 7a/b and I am doing in ground citrus. I am doing mangos and guava in an unheated greenhouse.
in an unheated greenhouse?? What are your general lows in winter outside and inside of the gh. What is the lowest temp that u have experienced in the gh , thank u :-)

K-Rimes

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Yep, I'm in Zone 7a/b and I am doing in ground citrus. I am doing mangos and guava in an unheated greenhouse.

A greenhouse is the move 100%. I get a solid 10f of protection inside the gh with just a few string lights. I get lows of 26-28f annually, but that translates to a comparably balmy 36-38f in the GH - perfect for chasing sub-tropicals.

I do like to push the zone a bit, I just think it's really hard if not impossible without a greenhouse. I recommend finding space for it OP!

Tropical Bay Area

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How much protection does an unheated greenhouse usualLy offer?
Growing tropicals in the sfo bay

K-Rimes

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How much protection does an unheated greenhouse usualLy offer?

Depends deeply on build quality, insulation and amount of sun it gets

brian

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Wouldn't an unheated greenhouse be vulnerable to a string of cold cloudy days?  At some point the retained heat is all going to be gone if it isn't being warmed by the sun.

I imagine it would help extend the growing season considerably, but I would plan on some kind of emergency heat.  Those propane heater attachments work really well.  I used them the first winter when my greenhouse heat wasn't ready yet.

fruitnut1944

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My greenhouse if unheated retains heat about one hour to at most a couple of hours. It's large, tight, and has a double layer inflated woven poly covering. The covering has heat retaining properties. But without heat the temperature inside at night closely follows outside. The only exception is a few degrees warmer inside when there is heavy cloud cover.

I do think there is some protection inside vs outside. But in 15 yrs mine has never been below 33F so I can't say if there would be less freeze damage inside vs outside at the same temperature. I say some protection because I've heard that often. But you never know what people are dealing with. One guy said his stayed 10-15 F warmer than outside without heat. Then several posts later said well it is open to a large insulated attached garage. What does that tell you, nothing about an unheated greenhouse.

I'm very skeptical of anyone who says their unheated greenhouse stays warmer than outside. For one thing how are they measuring temperature? It's not easy to get both inside and outside measured equally well. And just the physics of it says that it won't stay much warmer for very long. The R values of greenhouse coverings are about equal to wearing a T shirt in a blizzard. I've had 15 yrs with good thermometers to decide mine doesn't hold much heat very long. Last night mine fell to 47 with outside at 47.
« Last Edit: May 05, 2021, 09:07:17 AM by fruitnut1944 »

K-Rimes

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These Bluetooth thermometers are +-1f. The proof is here. On average 5-8f of improvement. Of note and this is very important this greenhouse gets blasted as the length is 24 long and the length is south facing. What is excellent is the average temp being so much higher. Plants really slow down below 40f.

My greenhouse is on an asphalt driveway which acts as a heat sync and the greenhouse is absolutely 100% full so lots of mass to warm up.

fruitnut1944

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These Bluetooth thermometers are +-1f. The proof is here. On average 5-8f of improvement. Of note and this is very important this greenhouse gets blasted as the length is 24’ long and the length is south facing. What is excellent is the average temp being so much higher. Plants really slow down below 40f.

My greenhouse is on an asphalt driveway which acts as a heat sync and the greenhouse is absolutely 100% full so lots of mass to warm up.

Is that with no heat and no ventilation? Outside you show 77 to 33F over 4-5 months. We have 44F temperature swings many days and averaged 55F each week in one winter I tracked. This winter 84 to 4F outside. In the greenhouse without heat or ventilation that would be ~130 to ~6F. I have seen +6F inside with heavy cloud cover. We have very little cloud cover in winter, Santa Barbara has a lot.
« Last Edit: May 05, 2021, 11:24:13 AM by fruitnut1944 »

K-Rimes

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The GH has gable fans that I have programmed to turn on at 86f - previously I had them set to 90f (during winter, and they hardly came on). I am at 2200' feet above the sea and rarely if ever have cloud cover - I am well above the marine layer from the ocean. I would wager we have fewer than 20 days of cloud cover per year and only 5-8 days of rain. It's high desert, basically. I regularly see 50f swings when the sun is out in the winter 40f ambient up to 90f when the sun is beaming.

For sure if you have cloud cover or trees that obscure your greenhouse when the sun is low on the horizon, the greenhouse will not provide much if any benefit. The only way it really works is if it gets hot inside, all the mass inside or the ground itself heats up, and then it slowly dissipates over night (and the gh is relatively sealed / insulated). I chopped down a ton of oak arms that obscured the gh this year so I expect it will be even better this winter.

I did have 300w of incandescent "hipster" lights, but I really don't think those make a big difference. On days that the power was out (this happens often in my rural location) the temps were basically the same. It just made it look nice at night.

850FL

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If you're zone pushing and not gonna bring your plants indoors, consider starting many marginal plants from seed. And preferably from varieties that are confirmed or suspected to be most cold hardy. For example, if I were in zone 8a I would try and source as many seeds from avocado varieties Lila, Pancho, Joey, Fantastic and Wilma as possible, and making sure those seeds were not pollinated by any variety less hardy than those. The seedlings may end up being slightly more or less hardy than compared to the parent/s since they will have degrees of genetic variation, but this can come to your advantage. Not to mention, I have noticed seedlings often are simply more tolerant of the cold than their clonal parents. This might have to do with a stronger taproot, I can't say for sure just an observation. For example, this past winter it got to 24F and all 5 of my air layered lychee saplings (brewster sweetheart and mauritius) had major branch splitting, however out of the hundreds of seedling lychees I have lying around unprotected (from those very same varieties), most of them only had very small twig, leaf, and new growth damage. But there are many factors involved.. The seedlings may have simply been out of the wind and much closer to the ground, which near the surface of the ground a bit of contained Earth heat always trickles out, so maybe that heat was just enough to prevent major splitting on those seedlings.. I couldn't say definitively.
But even a little dinky greenhouse or cover will help out greatly. The same winter event stumped all of my in-ground annonas, but I had a couple pots with freshly germinated seedling atemoyas in a TINY greenhouse under some bamboo, and none of them were even phased.
And on the topic of stumping, you will want to prune your marginal plants HARD. The larger the caliper of trunk and branches the MUCH greater chance they have of pulling through a bad winter event. You want the least amount of fresher smooth wood and the most amount of thick bark as possible on all limbs. For example, the same past winter event (24F) re-stumped a few of my in-ground mangos. The mangos had already been stumped twice over 5 years by other bad freeze events, so they have pretty thick caliper stumps. All of their smaller caliper branches that had no real wood were burnt down. However, the few inches of stump that are clearly woody pulled through just fine, and are sprouting new growth (which I will be pruning hard to hopefully get woody too). Same concept as with some of my in-ground annonas..
Also I'd recommend putting those prunings to use by trying to root them up, grafting, or whatever. Might as well..
Some people claim grafting a less hardy variety onto a cold hardy rootstock will increase hardiness of the lesser by a few degrees..
You mentioned jaboticabas. My sabaras were fine at 24F, not even leaf drop on any. I assume they could perhaps be okay even a few degrees lower. No idea how the other jabo varieties would respond to that degree of cold.
There are obscure varieties of annonas from nothern argentina/south brazil and uruguay that will withstand -6C. a.sylvatica, a. emarginata, a. ubatubensis come to mind. There are others too.
There are many fairly cold hardy citrus and avocados if you were interested. Wampee, kei apple, white sapote may be candidates too. feijoa, loquat are bullet proof. surinam cherry also takes the cold, though a couple of mine defoliated around 24F, but no branch damage. Someone on this forum told me his Luc's garcinia and some other garcinias actually withstood below 20F with not much damage. 12-15F was his low. It would be resourceful to not have a bunch of cold hardy plants unnecessarily taking up space in a greenhouse.
You could experiment by rooting cuttings and seeing at exactly what temperature or conditions they defoliate/die/become stumped before subjecting a bigger or prized specimen to those conditions, if you know what I mean. The results may surprise you.. but then again could be misleading because larger woodier plants are often more cold hardy than something like a small experimental cutting anyway..
Also you can try and mound your plants with a bunch of leaves.
And one last thing. I accumulate giant mounds of coffee grounds and have noticed they get VERY hot even in winter. Even small mounds. (significantly hotter quicker than a typical leaf & wood chip pile) Like 150F+.. It would be resourceful to utilize this heat energy, under a tarp and frame or something. You could have a big mound with a sealed tarp over it and pile all your potted plants around the mound still under the tarp. Or have a tarp set up and drag big totes of composting grounds under the tarp with the plants if you don't want the mound of grounds sitting directly on the ground. Just go around town and ask the coffee shops to save their used grounds and start accumulating.
« Last Edit: May 05, 2021, 12:19:01 PM by 850FL »

TheGivingTree

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This is great info. I am in my second year of collecting fruit trees and am now growing most rare zone pushers from seed. Working on solutions for keeping them warm, will be setting up two small greenhouses as well as putting wooden posts around the in-ground trees and wrapping with plastic.
« Last Edit: May 07, 2021, 06:43:51 PM by TheGivingTree »