Sun-burnt Cacti and Other Problems

[KanJe]

That's from my experience. Every genus is different and every species within them can be different again. Ariocarpus, Astrophytum, Copiapoa(not mexican I guess), Lophophora, Turbinicarpus, etc. all seem to prefer it in my house. I find any more light and they don't necessary start to burn but they grow slower and stress more, especially Astrophytum. Other people might get better results using other methods.

Edited July 5, 2009 by KanJe

[mutant]

Sorry to hear that Teotz! Which genuses did you loose? how are the youngish [from seed] going?

I had some problems myself in the begining of spring, when a couple of my cacti incl. two successful lopho on pere grafts with lots of pupping were burnt by too fast acclimatisation to direct light and they got orange rot on top - thankfully I saved them - it was the first time I used some commercail chemical on my plants... Linky for this older thread of mine

I give full sun to almost all of my cacti and trichocerei sure are benefited from it. Astro myriostigma also like it full sun I think. Almost every cactus can be acclimated to ful sun. I keep my gymnos as well are certain succulents and epiphytic tropical cacti in a more shaded place... the rest I keep in the roof, full sun You just have to remember that each new arrival needs this special acclimatisation...

[Teotzlcoatl]

Astrophytum myriostigma definitely like full sun! But the other Astrophytum (asterias) sure as hell don't!

[arnold500]

'

Hi Teotz

I am a member of another forum and this question has come up. The answer from an informed member was....

"What kills plants is not the temperature of the air, but the temperature of the plant. 50C should be quite tolerable for most plants, but 50C air will not remove much heat from a plant in the sun and it will rapidly overheat. Still air of any temperature is not effective at removing heat from plants, or pots, in the sun. No sun and the plant will only become as hot as the air, so it is almost irrelevant how hot the air is, assuming you don't somehow manage to make it 60C or 70C.

Red seedlings, also red adults and possibly sometimes white scorch, is caused by short wavelengths of light destroying chlorophyll. This can happen at any temperature and may even be more pronounced in the cold when the plant is not as efficient at producing and repairing pigments. "

The conclusion was air movement, but this is easier to produce in a controlled environment such as glass house with vents and fans.

Hope this is of some consolation.

A500

[Teotzlcoatl]

So.. air movement is the key to not burning my cacti? I personally think it was the light scorching the chlorophyll.

[arnold500]

So.. air movement is the key to not burning my cacti? I personally think it was the light scorching the chlorophyll.

yes the light, uv scorches but the heat kills.

I know I am new to cacti, but I think this is an interesting topic. i dont know how you are set up but my lophs are in the whole in terracotta pots and bowls. But when I look at them in the desert (photos!) of cause they are not, so my fear is that in cultivation they are able to heat to unnatural levels as their roots are "above" ground. Also many grow so well that their whole body above ground is far greater than the squat and partially covered button of nature. I have one which is about the size and shape of an small grapefruit that I am sure would perish in nature.

Also I recently saw a large cesposeta in a collection that was taken from habitat about 40 years ago (under licence) and had little resemblance to the perfect green clumps we see so often.

Just my thoughts

A500

Edited July 4, 2009 by arnold500

[Teotzlcoatl]

Yes, many cacti look completely different in habitat than they do in cultivation! Especially the slow growing cacti!

[mutant]

arnold, excellect contribution to the topic, thanks a lot. This quote you provided is very interesting, as well as your other thoughts.

[Teotzlcoatl]

Thanks for the help guys!

[tenacioustornado]

where's the pics, was it just astrophytums that got burned?

[Teotzlcoatl]

No some Lophophora got burned too! No pics

[Gunter]

My UV is 11-12 in summer. I give my cacti as much sun as possible, but they can burn if I do not transition them properly.

I have have little to no sunburn this year though, because I left most of my plants out and just covered them with plastic and provided heat for winter. It can get -20 F here, but seldom does.

[Teotzlcoatl]

Next year I'm going to take the acclimation much slower...

[san p]

hi,my peruvianus has a problem,if someone could please diagnose and suggest a treatment id be very grateful!

heres a pic

[Teotzlcoatl]

Oh it will be ok, just don't do anything to it, it should grow fine!

[san p]

ok thanks teotz' thats a relief. is it just some kind of natural scarring?sunburn maybe?

[Teotzlcoatl]

I think it's just some sort of scar, those are all over many of my Trichocereus. I think it's fairly natural for most Trichocereus to have something on them like that!

[mac]

san p im only having a guess because im curious about your plant

it almost looks like its has been caused by watering in full sun ? or just moisture because of the of damage where the water would sit

I have a tip that had slight scarring inside the ribs from being badly dehydrated before rooting & that larger patch may be where it had contact with the ground while drying the cut

has it always had this scarring or has it occurred while in your garden? , it only seems cosmetic skin damage but id keep a eye on the dry patches

Edited July 15, 2009 by mac

[san p]

hi,i think its been on the cactus for quite a while,i havnt been paying much notice to it until recently ,as the scarring was facing the wall so out of sight.i think you may be right that its been damaged from being wet and in full sun at some stage.

[Teotzlcoatl]

Alright my cacti are doing great now.