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What happens to highlanders without night temperature drop?


Romulo
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I don't know if I have written well the title..so sorry for my english!

So, I open this topic to get some information about people who has grown their highland Neps without the night temperature drop, and to ask how many degrees (more or less) have to drop temperatures at night to be healthy for the plant...

Also, anyone knows why this plants have to have that drop (the scientific explanation, not answers like " 'cause wild plants grow under that conditions")

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I can't give you a scientific explanation. It's more of a physiological thing, where the plant needs the drop (and usually cool temperatures) to either rest, or do some physiological duties. If they don't get it, plants get worned out. Results are similar to skiping dormancy in plants that require it.

Natural conditions found in habitat are just a starting point ... conditions known to work. It doesn't mean a particular plant won't grow under other conditions. It even doesn't mean that natural conditions are the optimal ones. Plants might be growing in very marginal conditions because of some other reasons (competition, lack of suitable habitats, etc...).

Experience says that most highlanders need those particular conditions. We would all love to be able to grow many of them in warmer areas without complex set-ups.

(maybe an admin can move replies to this topic in other topics here)

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I found this fact regarding the bornean highlands interesting;

'For every 1,000 m above sea level there is an average 5°C drop in temperature, equivalent to a 10 degree shift in latitude'

Found here;

http://www.worldwildlife.org/wildworld/pro...m0103_full.html

Very interesting link :read: So, N. rajah for example would have a temperature of 10 degrees less than a place at sea level...more or less...20º C, less at night (I have suposed that midd temperatures are about 30º C). N. villosa would be growing with 5ºC??

So Ilex, what happened when you grew highland Nepenthes under our climate?They just died one day?And if that happened, why are you sure that was because of the inexistent drop of temperatures? (I ask you because I think you are the most near example I have)

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Hi Romulo,

It is thought that the plants convert nutrients at a lower temperature and as a result in the long term, the plants weaken as if starving to death.

Juvenile plants apparently tolerate the "no drop" better than adults, and it has often been noted that plants like N.villosa for instance become more difficult to cultivate, the larger (older) they become.

This effect has been noticed in orchid culture also, resulting in plants not flowering.

Generally a diernal drop of 10c is considered suitable, though in my opinion the maximum temp should also be regulated according to altitudinal/lattitudinal observations and also increase the diernal drop accordingly. ie 10c drop from 30c will not suit ultra highlanders.

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I don't know if I have written well the title..so sorry for my english!

So, I open this topic to get some information about people who has grown their highland Neps without the night temperature drop, and to ask how many degrees (more or less) have to drop temperatures at night to be healthy for the plant...

Also, anyone knows why this plants have to have that drop (the scientific explanation, not answers like " 'cause wild plants grow under that conditions")

Hi,

I don't have any heating or cooling in my terrarium, it just sits in a window. I don't know how similar your climate in spain is to Melbourne (might not be so different), but I find that the conditions in my terrarium are more or less lowland over the summer and roughly highland over the winter. My few lowlanders tolerate the winter conditions pretty well, but do noticably better in summer.

The highlanders: well, some do very well over summer but others don't. My sibuyanensis does OK but its pitcher buds have a tendency to get burnt before starting to develop into pitchers. Many other highlanders tend to produce smaller leaves and pitchers. Also, their pitchers tend to visibly suffer in warmer weather and don't last as long as in winter. For example my sanguinea had about eight pitchers at the beginning of spring, some a reasonable size, but now at the end of summer it just has one or two very small ones. (and this is the same pattern as in the previous year). I find the plants recover pretty well over the cooler months, but I don't know if they can do that indefinitely.

Cheers,

Tim

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I get the impression that lowlanders can experience quite low overnight temperatures and still do well as long as the daytime ones are high enough. And likewise, I think highlanders can do OK with daytime temperatures that are too high as long as the temperature drops enough overnight. I could be wrong about this and I'll defer to the wisdom of more knowledgable and experienced growers. But if I'm right, then it's not so much a question of "how many degrees should the temperature drop overnight?", but rather "how cold does a highlander's overnight temperature need to be?".

Cheers,

Tim

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I grow my highlanders in pretty weird conditions: 35-27C days and 20-16C nights, with high humidity days and low(~30%) humidity nights. For anyone wondering, my 'set-up' is plants sitting on a rack beside a window, air-con only while I'm sleeping. No lights or anything else.

So far, I've noticed that heat stress causes the plants to stop pitchering and produce smaller leaves initially, but over time they adapt, the leaf sizes return to normal and the start to pitcher again. It may be a bit too early to conclude anything from my little experiment, since its only been 2+ years for most of the plants, but given that they've stayed alive for that long, I'm wondering if I should be breathing a little easier or not...

I think there's a combination of "how many degrees should the temperature drop overnight?" and "how cold does a highlander's overnight temperature need to be?" that Tim mentioned. Some of my neps do better during the hot season, when there's a larger temp drop, but some others, especially N. villosa, do much better during the rainy season, when the day and night temps drop to lower, but the difference between the day and night temps isn't as great. Anyway, the N. villosa is still small, I imagine it'll give a lot of problems when it gets larger. Stuff like rajah, eymae, lowii and khasiana all seem okay for now...

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As to a reason why a plant might need a temp drop was hinted at by ilex regarding how nutrients are converted by the plant at certain temps.

I know from growing bonsai that some trees that occur in snow covered mountain tops during winter have adapted to the cold by converting sugars in their sap to starches which prevents the water in the plants cells from freezing and thus bursting the cell membrane resulting in the plants death. To see what I mean try putting a carrot or stick of celery in the freezer and then remove it to thaw, you will notice it is now very soft.

I don't specifically know how highland neps have adapted to their cold montane climates but it would definately be something to do with nutirents, sugars etc that the plant can only do in these cold temps that was caused by their adaption to their colder living conditions.

I hope that gives a bit more insight.

Dave.

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Very interesting link :read: So, N. rajah for example would have a temperature of 10 degrees less than a place at sea level...more or less...20º C, less at night (I have suposed that midd temperatures are about 30º C). N. villosa would be growing with 5ºC??

So Ilex, what happened when you grew highland Nepenthes under our climate?They just died one day?And if that happened, why are you sure that was because of the inexistent drop of temperatures? (I ask you because I think you are the most near example I have)

Seems so, I was reading on another forum recently that the temperature of the highest bornean mountains often gets below 5 with ground frosts, this winter i've let my plants get colder nights than they have before, even opening the vents for an hour before i go to bed and certain plants, rajah in particular, have rocketed..

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Very interesting link :read: So, N. rajah for example would have a temperature of 10 degrees less than a place at sea level...more or less...20º C, less at night (I have suposed that midd temperatures are about 30º C). N. villosa would be growing with 5ºC??

So Ilex, what happened when you grew highland Nepenthes under our climate?They just died one day?And if that happened, why are you sure that was because of the inexistent drop of temperatures? (I ask you because I think you are the most near example I have)

The 1ºC per 200 m is what is considered normal, not just for Borneo.

In my area, and under my conditions, plants almost always get at least a 10-15 ºC drop at night, and highlanders are not happy at all unless night temperatures are cool. Drop is not the problem here. Some die very fast, others hang to live for years (rajah is able to do that when young). Even if temperatures go back to normal, it usually takes them a lot to recover. If its cool with no drop (rainy in winter), they also don't do as well, they somewhat slow themselfs ... and recover very fast once things go back to normal. They look somewhat in a dormant state, but perfectly ok.

Real highlanders just can't take my summers (yours are quite worse). More intermediate plants can. Maybe they are not happy in summer, maybe winters (the ones we used to have, we don't get them anymore) are a bit too cold for them and they slow for a few months, but they do great most of the year. Most lowlanders can take a bit of cold, specially if it's warm during the day, but our winters are a bit too much for them. They really only like our summers. Intermediates and highlanders will be ok as long as it doesn't freeze.

Yes, I've noticed many highlanders can take quite a lot of heat during the day if it's cold at night. Similar for lowlanders.

I had a chiller for a couple years, and when it broke for a couple days, I did loose some plants. That happened a couple times. I also lost some masdevallia.

My climate is very similar to Perth's in SW Australia, or the coast of the San Diego area in California.

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Has there been any study about the amount of time that the temperatures need to be dropped? Wasted opened the vents for an hour and the plants loved it. I read that to mean that after an hour they were closed...is this the case? That would seem that they do not necessarily need an entire night of temp drop.

I haven't figured out how to do a true highland set up just yet. It'll probably involve a tank in the basement that is heated during the day.

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Hiya,

Yeah I close them again when the temps dropped to just around 7 degree's or so, once the temps down it tends to stay that way during the British winter, the heater comes on at round 5 and stays on till 7 degree's..

I guess it lowers the overall average night time temps by bringing them down quicker.

Laters.. Wasted

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If the terrarium is well insulated (should be if you want to have a different temperature than the environment), once you lower the temperature it tends to stay low for a while, as cold goes down and doesn't scape easily.

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So, reading what you all said, I can tell as a conclusion that, in most cases, people can grow well highlanders with a well night teperature drop and with not very hot climates...

In spite of that, my N. maxima for example grow very well into my house (25 - 20ºC in winter, 5ºC less at night more or less) and when I take it out of my house (Now is 15 or 12ºC and it's very windy), developing pitchers become black and they die.. I think maxima is a highlander, isn't it?

(My N. maxima isn't a young plant)

Cheers, Romulo.

Here is some photos of my maxima:

detalle2jarrosaj2.jpg

maximavistamximans6.jpg

maximavistamximans6.f529a04e31.jpg

Edited by Romulo
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Im not sure but I thought n. maxima has lowland, intermediate and highland forms with ranges from sea level to 2000 metres???

Im sure someone will correct me.. ;-)

Really? So anyone can answer my question (if my maxima is the lowland form)?

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Romulo,

Here's a thought: maybe the pitchers die outside because its very windy, not because of the temp. If there's a drastic change in humidity, the plant can come under stress and that may happen...

Can't really answer your question though, I'm not sure what the difference in the forms are. :thumbsup:

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Romulo,

Here's a thought: maybe the pitchers die outside because its very windy, not because of the temp. If there's a drastic change in humidity, the plant can come under stress and that may happen...

Can't really answer your question though, I'm not sure what the difference in the forms are. :thumbsup:

I think it isn't a humidity problem...here in Murcia I usually have 70 or 60% (outside) of humidity!

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maxima is highland(800-2500 from sea level)..but it can grow well in lowland..

800 metres aint exactly highland though, that's a massive range and don't a lot of ll plants extend beyond that? Surely it depends what location your particular maxima was sourced from?

The method of classifiying plants by hl or ll etc seems a bit pointless for a plant with such variable range.

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Maxima is whatever it wants to be. 600-2500 is the actual recorded range, but it has been found by hobbyists much lower, and possibly slightly higher than that. There are pictures online of maxima found at 400m, so the "official" data is either outdated or blatantly wrong.

Surely it depends what location your particular maxima was sourced from?

Bingo.

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I think it isn't a humidity problem...here in Murcia I usually have 70 or 60% (outside) of humidity!

Ah, okay. Over here in Singapore, the humidity outside is always above 90%, but when its windy the humidity can drop by quite a lot. I've had the experience of moving one of my neps from a non-windy spot the garden to a windy spot in the garden and it went under stress with the pitchers drying up/dying and the leaf edges started to bend. Still, my nep was a lowlander(an amp) and those tend to be a bt more humidity sensitive...

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Ah, okay. Over here in Singapore, the humidity outside is always above 90%, but when its windy the humidity can drop by quite a lot. I've had the experience of moving one of my neps from a non-windy spot the garden to a windy spot in the garden and it went under stress with the pitchers drying up/dying and the leaf edges started to bend. Still, my nep was a lowlander(an amp) and those tend to be a bt more humidity sensitive...

I was going to make a similar point, humidity for plants is a bit like windchill factor for humans in the way it works. The faster the wind blows, the lower the 'effective' humidity. In a decent wind, the effective humidity can drop to less than 20% very quickly.

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