Mango in central Italy: an experiment.

[Pancrazio]

This thread wants to be a report of my experience with my attempt to grow and fruit sucessfully a mango planted in ground in central Italy, to be precise in Florence (http://en.wikipedia.org/wiki/Florence).
My hope is to make something new and usefull for every "zone pusher" who wants to grow his own mangos in his own backyard. Basically i noticed that on internet there is a lack of data on this issue, and most of people who write about mangos are either in one of those two situation: in a place where clearly mangos (or other tropicals) grow without any help (except maybe some cover during brief cold snap), or either in place where mangos need to be kept in pot and brought indoor because even the soil become too cold. I haven't been able to found nothing for people with a reasonably long and hot summer and a mild winter, but still too cold and long to keep mango in ground with a light cover. This is what brought me here.
As you may have already understood, english isn't my primary laguage. So, it very likely that this thread will be full of typos, sintax and grammatical error. I'm sorry for that.

The Idea.

Basically, the idea behind my experiment has been very simple. I knew that some people grew mangos in Sicily, because i bought some fruit at the grocery that came from there. I also knew that, with an insulated and heated greenhouse, you can also grow them in Germany. "So," i reasoned "there's a place between those extremes, where you can grow them with a simple unheated cover, removable in summer"
I started with some research at the end of 2010 and found that an user on gardenweb were able to fruit mango in middle California (http://en.wikipedia.org/wiki/San_Rafael,_California ); that place has cold summer compared to ours, but also hotter winters. Still the user had used a very minimal cover, and i planned to cover my plant much more.
Moreover i found on gardenweb the struggle of puglvr1 with freezes and her ability to minimize and keep mangos in pot, wich gave me the convinction that i could manage the size of my plant and keep even a plant like a mango under control. This was essential because the cover, once built, had to be kept of fixed size.
The more i read about mango, the more i convinced myself that even if most of their biology is similiar to a tropical plant, as far as tollerance for cold, mango beahave in a similar manner to a very tender subtropical, being able to withstand even extended periods of low temperatures and even some dip under 32°F (0°C) if they are brief enough.

[Pancrazio]

The place.

Once i started to think that it was doable (or, at least, not too unrealistic) in my zone, i needed to choose a place where to plant my mango. For everyone who is out of the optimal climatic zone for a mango there isn't much choice: you gonna want all the sun possible for you plant. Heat is even more important than sun because if winter nights go under freezing temperature the plant will die: but the aren't many place with heat and not sun, except maybe the exterior of an house heated from inside. The slow realease of heat from an house in winter can raise the temperature inside the cover, but an optimal sun exposure is even more important because i needed the plant to be healty and bear fruits, wich isn't possible if it doens't receive enough heat and sun in summer (and during summer the houses aren't heated).
So, once understood that the sun is the most important thing, i have had to choose a place where the sun shines during all the summer and all the winter, to maximize its benefits.
Still, the sun hasn't magical proprieties, and during nights it goes away, so the optimal exposure must be combined with a place that can keep the heat given by sun at least for some time. In my proprety, luckily, i had the right spot. A place exposed at south, with a wall at east where i could lay my structure on during winter. Walls keep heat in 2 ways: 1) they insulate very well, better than any removable structure 2) They have a decent termal mass and can absorb heat during the day and slowly release it during the night.
Please notice that this is a sub-optimal choice. The optimal wall should have been on the north of the structure (facing south) because i would obtain 3 effects this way: 1) Defends the plant from nothern winds 2) Don't cover the light from sunrise, wich is critical because that light arrives during the colder hours 3) Same insulation/thermal mass as above. The point numer 1 isn't a big issue for me, but still make my structure suboptimal. The point numer 2 instead can be a big issue expecially during hard freeze.
How i choosed the best place for my mango? I use that nice little tool from University of Oregon (http://solardat.uoregon.edu/SunChartProgram.html ). This tool was intended to choose a place for a solar collector. But since the structure during winter should beahve like a solar collector, this tool works fine.
I followed the instruction listed here to use it: http://www.builditsolar.com/SiteSurvey/site_survey.htm
Please note: it's not easy to understand where true solar south is, but you are going to want the solar south, not the magnetic south.
After i fixed the place, To be sure that the soil had a good drainage i mixed to the soil 200 L of sand.

[Pancrazio]

The structure.

Once I have had my spot decided, i started to think about what kind of structure i wanted. For sure i wanted something that could be putted down during summer: i though that our summer was hot enough to let the mango enjoy a bit of "fresh" air during summer months. Moreover, air circulation, as who owns a greenhouse already knows, lets the plant stay healty.
So I thought that the possibility of removing the structure during summer was mandatory.
Now, concerning the material of the structure, i evalutated wood, iron and aluminium. The first is easy to work, lightweight and easy to find in bricolage centers. Too bad wood is perishable. Iron can last long  with appropriate care, but is heavy and not easy to work with. Aluminium is nice, lasts for ages, lightweight, but is pricey. I choosed for wood, because i wanted to build it by myself, and wood seemed the most failproof solution. In addiction wood has another advantage: when you build a structure tha must be insulated from outside, you must pay attention to the thermal bridges. Those are the point that can bring heat from inside out and are made of good heat conductors. Basically, if i used iron or aluminium, the entire structure could have been a big thermal brigde, putting in contact to cold air outside with the hot (relatively speaking) air inside the structure. This is WHAT you don't want.
Now, what kind of structure should i have done?
Basically i wanted to maximize the solar imput, for the reason said above. In addiction, since i suck at building things, i wanted to keep things as simple as possible. On the net there are a lot of structure made to obtain this effect, they are called solar greenhouses.
I used for inspiration mainly two sources: many project listed here:
http://www.builditsolar.com
and the greenhouse showed here:
http://energyfarms.wordpress.com/2010/04/05/solar-greenhouses-chinese-style/
http://www.ece.vill.edu/~nick/solar/solar.html
So i built a nort wall to use for themal mass, and anchorage of the structure, and i putted some concrete block on soil for fundation. I filled the block of the north wall with dirt, wich increase their thermal mass and adds insulation. In my experience the point on wich this kind of strucure touch the soil is crucial, because often some air circulates there, if it isn't well closed. I didn't wanted the air from inside to go outside because it means a colder structure, both during day and during night.



This is the draft plan i ended with (the actual true plan with measures is on paper. :p ). OF course, this is a side view of the structure.
How i choosed the angles in this plan? Well, the only thing i kept in mind was my latitude, wich is 44°N. This mean than on summer solstice the sun is at (44°+23°) about 67° Above the horizon while during winter solstice the sun is (44°-23°) 21° above the horizon. At 23 September and March instead the sun is at same height as my latitude, 44°. I ignored everything between March and September, because the greenhouse should be useless in those months. What is left to me? The 21° angle of the sun in Dicember, and the 44° angle in March september. But, is dicember the coldest month? No, it isn't. Instead the coldest month here is January, so i wanted to maximize the efficiency of the strucutre in those days. On January days are longer, this means that the sun is a bit higher on horizon. On those days the sun is 25° above the horizon, so if i want that the sun will forum an angle of 90° with the strucutre i must get the angle A at 65°. For keeping everything very simple i reduced it to 60°.
The other importat angle is the angle B, and it is 45° because it is very simple and very close to my latitude. Between September and March sun will be LOWER than 45, so that roof won't make any shadow inside the structure.
The northern has been made 90 cm high
Then i ended with a south roof, wich takes the sun, and a north roof, wich is basically just a way to protect the plant from cold air and rain, but it is also an heat loss. I made those two of different material: the south roof is made of polycarbonate, the north of polystirene to reduce the heat loss. No sun comes from north, so no need of a transparent root there.
For many reason not related to efficiency (local laws, economy, etc.) i decide to make te structure 2 m x 2,1 m, and 2,1 m high. Please note that since some agles are fixed and related to your latitude, there is a relation between height and width of the structure. So, if you want it bigger you can make it even taller, and vice versa. Of course, the bigger, the better, since bigger object have an higher thermal mass.

[Pancrazio]

The heat.

At first, as you may have noticed, i tought to make it completly solar passive. I didn't wanted it to consume electricity.
The concept was: "since water has an hig thermal mass, if i put enogh water inside the structure this will make days colder and night warmer". Since the average temperature for the coldest month in my city is well above 32F (0C) i simply needed to keep this temperature long enough. So, i filled the structure with some oil cans (5 L) some plastic cans (20 L) ans some drums (100 L). I have putted inside something like 500 L of water, in containers of different sizes, all around the plant.
After this i panicked. I thought that just in case this shouldn't work would have been wise to make something to save the plant in wrost nights of winter.
I found a chick heater that was composed by an infra-red lamp, and i tougth to add it to the structure. But first measures in last November in the structure convinced me it wasn't needed, so i never installed it.

[Pancrazio]

The plant.

After all this time spent on doing my best for this structure i found myself asking what kind of plant was the best for this experiment between the ones i had at disposal. The first question was: since the space is limited should i pick a dwarf or a vigorous grower? Well, even if it is counterintuitive, i choosed the grower, because if it will get some damage i should be able to recover quickly, and some kind of damage is more than possible when you do an experiment.
I had a disposal the following varieties on this side of the ocean: Kensington Pride, Glenn, Tommy Atkins, Keitt, Maya, Van Dyke, Osteen, Kent. These are hard to find in italy, but some sources indicate that you should be able to find them around, so i started searching. After 4 months, i found hte plant i choosed, a Glenn.
Well, i choosed Glenn because it can grow at decent rate, so i hope to be able to let him grow if it becomes damaged. Still it can be pruned and kept in shape. It should be a decent bearer, wich is important, of course. Plus, is said to be very disease resistent, and our winter is very humid. Taste review are always favorable, and the main flaw of the cultivar (the bland taste of the fruits in humid climates) won't be a problem here, where summer is the dry season. Seemed to me hard to beat, honestly.
I planted it around the first days of may in 2011. I already had some flowers and tiny fruits when i planted it.

[Pancrazio]

The pictures.

This is the plant few days after being planted in soil, May 2011. The masonry work was finished in February, but i started to build the structure just after the summer.



Little (VERY little) fruits at the end of the first summer. I still don't know what happened, but they lacked embryo.



This is the skeleton of the structure. The picture has been taken in a day close to the equinox. As you can see the wood of the north roof cast almost no shadow.



This is the structure finished.



Side view.



North view.



Conclusion.

I hope you may have found this interesting (or at least, not too boring). This is far from an end, bu so far i'm pretty happy with it. The structure has been able to keep temperature about 10C hotter inside than outside.
Too bad this february italy has been hitted from the wrost cold weather in last 30 years, wich has stopped my experiment abruptly. Last two weeks we have had about 15°C under the average temperatures. No sun, and no day with temperature above 32F for a week. This structure wasn't built to resist such extreme weather, so i needed to put in an heater. But, for the record, those where the minimum temperature taken inside/outside the cover till february:

Before Chisthmas:
Outside: -5,2 Inside: +4,5

25 dicember 2011 - 31 dicember 2011
Outside: -3,1  Inside: +6

1 January 2012 - 7 January
Outside: -2,6    Inside: +6

7 - 14 January

Outside: -4,2  Inside: +7

14 - 22 January

Outside: -5,9  Inside: +5

22 - 31 January

Outside: -5,2  Inside: +6

(You can see last January in my city here: http://www.tutiempo.net/clima/Firenze_Peretola/01-2012/161700.htm )

[JoeP450]

Wow Pancrazio I am truly amazed at what you have built to achieve your goal of growing this mango. Two days ago I watched Noel Ramos video of his trip to puerto rico and his description of the pulasan makes me want to build a green house to try and fruit one in my back yard here in FL, I just cannot imagine a fruit more delicious than lychee, I have yet to sample a pulasan but someday I will, soon!

Keep pushing the limits!

_JoeP450

[MangoFang]

...so Pan....how are things now are a couple bad bad shots of Arctic cold the last 2 weeks?

Have you unwrapped the Glenn yet to check on it's condition?

mangoFang

[adiel]

Congrats Pancrazio.  A great accomplishment.  When does your mango bloom?

Adiel

[lycheeluva]

amazing experiment and amazing report- looking fwd to the updates

[puglvr1]

Great to see you here Pancrazio! Yes, please keep us updated on how the Glenn is doing. We're all pulling for you. Good luck!

[Pancrazio]

@JoeP450: Let's hope it will keep up its reputation! I also have hear nice things about Pulasan, but i doubt i will be able to staste one of them anytime soon. Anyway i don't know if this can work in florida, but for sure some kind of work to keep a pulasan happy can be done. The hardest thing, i think will be find out enough information to make a good plan. This is always the hardest part, in my opinion.

@MangoFang: Oh, Gary, i think i have done an horrible mistake. Just today i removed the frost cloth and the bubble wrap and the plant was fine. I also checked the temperature and coldest has been 3°C just next to the grafting point. I have only found two dead leaves, copper coloured, i think frost damage. I have been convinced to do this by the shiny hot sun we got today (46F). Tonight temperature dropped, and now is 23F and going down. Usually i wouldn't be worried but the heat inside the greenhouse has been depleted in last days, so i don't know it it will be alive tomorrow. Wuold be really ironic (and to be honest, very very stupid) if i would lose it now, the first normal day after those two weeks.

@Adiel: It has some bloom spikes right now, but they grow VERY slowly. But please refer to message sent to mangofang.

@lycheeluva: There will be more, i hope.

@puglvr1: Good luck to you also, Nancy! We won't be happy till this winter will be finished, right?

To everyone: Thank you for reading the entire mess i putted above. If you have been able to finish it you are either very patient, or really a mango maniac. 

[fruitlovers]

Wow Pancrazio I am truly amazed at what you have built to achieve your goal of growing this mango. Two days ago I watched Noel Ramos video of his trip to puerto rico and his description of the pulasan makes me want to build a green house to try and fruit one in my back yard here in FL, I just cannot imagine a fruit more delicious than lychee, I have yet to sample a pulasan but someday I will, soon!

Keep pushing the limits!

_JoeP450

Did Noel really say pulasan is more delicious than lychee? If so i would i hve to say my taste buds don't agree. Pulasan comes in a close second, but lacks the wonderful fragrance that lychees have. Also pulasan is not as juicy as lychee. Anyway, i still encourage you to try to grow it!
Oscar

[adiel]

Oh, Gary, i think i have done an horrible mistake. Just today i removed the frost cloth and the bubble wrap and the plant was fine. I also checked the temperature and coldest has been 3°C just next to the grafting point. I have only found two dead leaves, copper coloured, i think frost damage. I have been convinced to do this by the shiny hot sun we got today (46F). Tonight temperature dropped, and now is 23F and going down. Usually i wouldn't be worried but the heat inside the greenhouse has been depleted in last days, so i don't know it it will be alive tomorrow. Wuold be really ironic (and to be honest, very very stupid) if i would lose it now, the first normal day after those two weeks.

Pancrazio, get yourself an electric heater with a thermostat like the Dayton 3VU33:





This way you can turn it on at any time you have a "cold" emergency.

Adiel

[Pancrazio]

I used an electric heater during this cold spell (i mean, since 1st of February). I'm planning to detach it during next few days, based on temperatures.... for sure it works, even if i think it is not the most efficent device, cost wise.

The plant is still alive, and i hope the wrost part of winter is gone.

[JF]

Great project Pancrazio, thanks for putting it together! Your data will be useful for folks in the Midwest or Northeast.

JF

[Pancrazio]

Your data will be useful for folks in the Midwest or Northeast.

This would be really awesome. I really hope it.
I next days i'll try to translate every misure in Imperial and metric units.

[samuelforest]

I hope you'll get some fruits Pancrazio

[Pancrazio]

I hope it too! Would be really nice!

[Pancrazio]

For those who may be interested, my mango did make it trough this hard winter, and now is in bloom! I'm so happy about this! 
Now i need to seriously start to think about some formation pruning, to keep it compact. I need it to stay under the cover!
(I also need to learn to hand-polinate this because under the cover there isn't any wind and there aren't bees... this was a unforetold issue)

[Felipe]

AWESOME!

[lycheeluva]

Great job!
Is it not warm enough now to remove/open the cover? are there no flies or bees out yet?
My mango flowered during the dead of winter- so i directed a fan onto the blooms and also ordered a few hundred flies over the internet- the flies did not appear to pay much attention to the mango blooms. i rarely saw them on mango blooms though i did get plenty of little mangoes forming-not sure whether this was due to the flies or the fan or none of the above. i will say that by the time my last mango flowers opened, most of the flies had died and i only got 3 fruits to set on that pannicle, though interestingly, all 3 fruits  are progressing so far (usually less than 1% of mangoes that form make it to maturity). so that annecdote make me wonder if the flies did indeed pollinate the mangoes even though i only saw them on the mango pannicles once or twice ( i only observed the mango trees about 10 minutes a day, so maybe the flies were on the mango blooms when i wasnt arround).

in sum, my suggestion to you is open up the cover if it  is warm enough in the hope it is now warm enough to flies/bees outside to pollinate.
if that isnt feasible, see if you can buy some flies over the internet, and direct a fan onto the pannicles.
i have a slight suspicion that some mangoes will set fruit without wind or insects- but thats just a wild guess

[Tomas]

Hi Pancrazio,

Your new name from now on is da Vinci! That's really amazing what you have built.

Tomas

[Patrick]

Nice work! Time for a Mangosteen! 

[nullzero]

Congrats on the blooms! Lets hope you get plenty of mangoes this year! Its going to be a lot of future work to keep the mango tree contained in the enclosure. I think Julie would of made a great fit for the enclosure (due to its stout compact form), perhaps if you do a second enclosure you can grow a Julie. Glenn though is a great selection, from what all the mango addicts say .