Nepenthes and frost free Greenhouses

[manders]

Is anyone overwintering their nepenthes in a frost free greenhouse? I have a few out this year with mixed results, wondering if anybody has tried any other species?

I'm trying to keep it ~3-4C minimum but it did go down to -0.5C for a very short time (no ice formed).

So far:

Singalana (maybe ok, some sign of stress)

Glabrata (ok)

Diatas (ok)

Densiflora (ok)

Ventricosa (ok, some stress)

Spathulata (ok so far, cutting not plant)

Maxima (not ok, trial abandoned)

Gentle (not ok, trial abandoned)

Muluensis * Ventricosa (damage to young shoots, trial abandoned)

[rsivertsen]

I've grown quite a few Nepenthes outside in a greenhouse in a temperate zone through the cold winters at these temps and a few times also had them exposed to slight frosts with mixed results. The N. ventricosa "porcelain form" showed no signs of stress, while the smaller red forms nearly died. The same with the red forms of N. alata while the green forms died back to the pots and came back from the old growth deep in the pots. N. fusca, steno's and a few others also fared well, but all the lowland stuff from bicals to raffs, gracilis and amps were all in very bad shape, including hybrids such as N. dyeriana and N. mixta. Curiously, the all N. truncata plants showed no signs of stress. - Rich

Edited January 1, 2010 by rsivertsen

[manders]

Hi Rich, I had a lowland and a highland truncata at around min 7-8C last year, the lowland stressed badly and took months to recover but the highland was unaffected, what variety were yours?

[flycatchers]

I have a few in my Sarracenia house where I am keeping just above freezing. So far the N. ventricosa x maxima, ventricosa x inermis, fusca x maxima & khasiana x ventricosa look fine.

Its often curious why some plants stress and others do not. Ever since getting my (highland?) N. alata (true form) it has stressed in the autumn/winter with brown leaves & pitchers. Even with one of my plants fairly close to my fan heater (but not too close!) it has developed these patches. Similary affected plants are the N. maxima x mixta (though the reverse cross is fine!), N. rokka exotica.

Of my lowlands only the N. sumatrana seems unaffected by cool temperatures. While not growing under my conditions very fast it has got through 3 winters without any damaged. All my other lowlands have to be moved indoors very early in autumn to stop too much stress. Even so my N. campanulata X N. veitchii has gone black and looks on its last legs

Am going to move a few of my spare Heli into the Sarracenia house shortly to see how they fair.

cheers

bill

[Phil Green]

I've quite a few in the yard which have been down to at least 4C - that was at about 8-9am in the morning. I think the short daylight is as bad as the low temps for them. Mine have been happier for the last 2 winters since they get extra light for the fluor tubes.

Bill - I expect the Heli's will be happy in there. As I mentioned in another post, I've had a seedling in the greenhouse which has been down to at least freezing and was fine - but I 'lost me bottle' and brought it in.

[manders]

Phil,

Were they at cold temps regularly, the damage seems to be cumulative over long periods, and which species?

Bill

I was tempted to try at least one heli but haven't done it yet. I never thought of trying the sumatrana! having problems getting that one going again after it struggled a while back.

I had a campanulata at 8C last winter and it looked very healthy, as soon as the temps warmed up it went black and died!

It would be great to have a decent list of neps (&helis) that can take the cold then i could divide them up better and save a load of heating!

[gardenofeden]

I keep my greenhouse at 5°C minimum.

Nepenthes singalana, ventricosa, ventricosa x inermis, bongso all do fine

muluensis x lowii suffers slightly, recovers quickly in the spring

spathulata suffered a lot and started to decline, I eventually sold it, it was happier above 7°C

Heliamphora heterodoxa x ionasii, heterodoxa x minor do OK at these temperatures, few other survive long-term for me. I think Manders is right about cumulative effects, the odd dip of temperature, even down to less than 5°C, may be okay but prolonged temperatures are the ones that do the harm. I feel that in northern England it's not the extremes of temperature that dictate what I can grow but for how long lower-than-ideal temperatures and light levels persist over winter. i.e. They can take the lows as long as they get the highs!

[Phil Green]

Phil,

Were they at cold temps regularly, the damage seems to be cumulative over long periods, and which species?

The Neps have regularly had temps down to about 6C (lowest I know of was 4C, but it doen't have a min/max so I've no idea the absolute lowest) and never above 12C (was 10C but I upped the temp). The heating cable isn't powerful enough for really cold nights. This has been for this and last winter. The winter of 07/08 they were similar or a tad higher (in the greenhouse), but they really suffered - not blackening, but very tiny leaves on what little growth did happen and then took months to properly start growing again come spring. The only difference for the last 2 winters is the lights to extend daylight and although they do still slow up, the growth isn't as tiny and they don't take so long to get going again.

Right now it's 8C in there - with the lights on. Just turned them off and they add a couple of degrees to the temp, so they are gonna be at least down to 6C tonight.

The Heli seedling is a pulchella.

I'll have to list the Neps tomorrow, as I've no idea whats in there - and it's cold outside (but last year just about everything I had was in there).

Stephen - what do you call highs - for winter.

Edited January 1, 2010 by Phil Green

[rsivertsen]

Hey Manders, I had a mix of over a dozen different clones of N. truncata, some with glabrous petioles, which seem to be the lowland forms and some with hairy petioles which seem to be the highlanders, and they all seemed to fare well through the cooler temps, although it may have been due to where they were in the greenhouse at the time, some were higher up, and others were closer to the floor. The worst came one night when a pine branch broke off and fell through the greenhouse roof one night during an ice storm when the temps were only in the teens (F), and by the time I got out to them by 6 AM, I noticed small ice crystals had formed on the hairs of several Nepenthes leaves, including N. hispida, fusca, steno, maybe veitchii, and a few others; I thought for sure they were all going to die, but to my surprise, many of them never even showed any adverse effects or even slowed down. The lowlanders were mostly dead or nearly so, hanging limp over their pots, all brown and lifeless. - Rich

[gardenofeden]

Stephen - what do you call highs - for winter.

Well this time of year it hovers around 5°C, without the sub-zero temperatures it's probably 5-10°C on the whole, but I have not kept a comprehensive record, on sunny days perhaps getting up to 15°C. Most winters I can get several weeks of "around 5°C" though, which with low light levels (no supplementary lighting) really doesn't do the plants any favours in my opinion.

[Rob-Rah]

H. heterodoxa does fine for me just kept frost-free (a degree above zero).

N. khasiana is as cold-tolerant as the books suggest it should be, but does appreciate warmer days.

[-=Joel=-]

I now keep mine at a lowest of 6.5C. All the neps seem to do fine and even continue to flower & grow. Haven't a clue how relevant it is but I have a constant flow inside the greenhouse to prevent stale air & also helps to prevent cold spots within the greenhouse.

[Phil Green]

OK, I've checked what is in there.

Temps last night at least down to 5C, today no higher than 10C (except when I open it and temp plunged back to 5C).

Happily growing - if slower.

mikei (barely even slows)

hamata (barely slows)

sanguinea (growing fine but slower)

mira (fine but slower)

stenophylla (slower)

Wistuba's 'eymae' (maxima ?) - (fine but slower)

talangensis (fine, slower)

burkei (fine, slower)

diatas (fine, slower)

mira x lowii (fine, slower)

mira x adnata (fine, slower)

spathulata x mira (fine, slower)

BE's sib x hamata - whatever it is (fine, slower)

veitchii x stenophylla (fine, slower)

talangensis x veitchii (fine, slower)

and many more last winter, again fine with the longer hours of light.

Probably of more use, would be those that didn't come through last winter well under these conditions :-

albomarginata (Cameron Highlands) - slowed to a stop and tiny growth. took a while to get going again.

bokorensis - slowed to a stop and small spring growth, slow to get going again.

splendiana x (spectabilis x veitchii) - Very unhappy, slowed to a stop and took most of the year to get going again.

splendiana x maxima - slowed to a stop and smaller growth. Didn't take as long to get going as the others.

ventrata - slowed right down and smaller growth. The first winter with natural day length one almost died, but regrew from basals.

Also N. kongkandana stops growth at temps ranging from 8-12C - I've had to put it back with the 20C+

So for me, I find most highland species and hybrids are fine with night temps regularly down to 4-6C and days around 8-12C if given 12+ hours of light. But many really suffer under those same temps if only given reduced natural daylight hours.

Edited January 2, 2010 by Phil Green

[Rob-Rah]

H. heterodoxa does fine for me just kept frost-free (a degree above zero).

N. khasiana is as cold-tolerant as the books suggest it should be, but does appreciate warmer days.

I thought I'd say more about this (even thoug this thread was about Neps and not Helis in the first place)..... I just popped into my greenhouse, which hit -2C inside last night. The current air temperature in there is now around 2C and the water trays are still frozen solid. However, all the plants, including H. Heterodoxa still look fine, with no signs of cold-related problems.

Cheers.

[rsivertsen]

If your Heli' plants were exposed to a solid freeze, it coult take a week or two to show signs of the damage, even death. Nepenthes show their damage right away. - Rich

[Rob-Rah]

If your Heli' plants were exposed to a solid freeze, it coult take a week or two to show signs of the damage, even death. Nepenthes show their damage right away. - Rich

I've been growing H. heterodoxa under these conditions for almost 10 years. No problems. It's only a few nights a season that things get that low.

[Stefan P]

my only experience is a N. maxima and x ventrata down to around 4ºc, without signs of stress...

I shall maybe try this next dormancy

[flycatchers]

Update:

Both khasiana x ventricosa plants now brown & limp after prolong cold period. Ironic considering the cold hardiness of khasiana! Will keep to see if they resprout but now moved to warmer Neps house.

Other cold damage to my biggest rajah plants. Leaves browned and spotted. This was in the highland house but were on the floor. Last winter was ok despite colder conditions.. Though this winter the burnt out thermostat did allow the temperature to drop to 5c for some hours. And that reading was from the staging and not near the floor. Plants moved to warmer area.

Roll on spring!!

bill

[Phil Green]

Sounds like this winter has been a bit rough on you Bill.

Update on my outside growcase - temps went down to 2C one night, and all still looks fine.

But I'm glad the milder weather has arrived.

[rsivertsen]

The red forms of N. ventricosa are NOT tollerant of even mild frosts, while the "porcelain forms" are! - Rich