So all my cactus i have bought has either come from California or Arizona. All of them were grown year round outdoors. I have brought my cactus INDOORS for winter and so i can look at them for hours on end. I have them all in front of a huge window that has a screen on it. So i dont get 100% sun .. id say like 70% sun? I have only watered them one time very lightly.

My question is, how do i avoid them getting etiolated? I understand it has to do with lighting, and watering. Is having them in my window with not full sun but decent sun and light to no watering until march 1st going to etiolate them or no?

When moved from outdoors to indoors there is nothing that can prevent etiolation short of intense artificial lighting and climate control that involves fairly precise temperature ranges.

One can prevent or reduce it by slowing plant metabolism by lowering the temperature. Plant metabolisms are linked to enzyme function which is mediated in part by temperature, as well as energy input(light) and nutrition (macro/micro nutrients, C02 and H20). The easiest thing to control in this is temperature, simply limiting water will not always work unless you keep the temps lower, the exact range to target depends upon the specie or genera in question but tends to be 40-50*F or so

well shoot. Sounds like i need to place them all back outside. Should i begin watering them after placing them outside? the temps here are 40F(night)-75F(day) until march.

Put some outdoors and some indoors. Compare notes. Report back.


JBArk

i have a problem with favoring plants when they are separated so i tend to keep them all together otherwise they some how know and it effects their growth heh.

I don't think it's favoring. It's more like experimenting to find out what works best. If you do the same thing with all your plants then how will you ever know what works better?

the simple solution would be MOAR LIGHT

To avoid etiolation:
¤ If your someplace that never freezes, leave them outside all winter and water far less.
¤ If you have to move them indoors stop watering them a month before moving, and dont water at all when indoors.

When theyre indoors under lights or behind a window they will etiolate if they grow, so either dont let them grow or learn to love cacti shaped like a sine wave.

I agree with auxin. I personally choose the second option during the winter. I leave my plants in low light areas that tend to get pretty cold but not freezing in my house. I don't water until spring and I haven't had issues with them getting etiolated.

Plants really have to get quite short of light before etiolation becomes a problem. When I lived in the UK, a country not known for its abundant sunshine, my cacti lived behind windows and I never suffered from any etiolation.

not really... if you bring a cacti inside from a warm sunny climate, say California- they will stretch and grow skinny if not put in to dormancy

if you grow them inside by a window in the UK they will never achieve the girth they would in a hot sunny outdoor environment in the first place....

That is my temperature range in winter - all my cacti live outside in cold frames all year round. I cannot grow Melocactus - too cold for them - but overall they love it here.

Meaning what???? I was relating my personal experience of growing in a dull climate!!! And that is exactly what I found.

meaning this sentence you wrote is not very factual. nice edit job on my quote btw. you removed the sentence i was referring to.

""""Plants really have to get quite short of light before etiolation becomes a problem.""""

Totally agree and reiterate with that - cacti do have to be very short of light before etiolation becomes a problem. And it is my experience that sufficient light comes through a decent size window in the gloomy UK in winter to avoid etiolation. Jeez I grew in the UK for 44 years before I moved to sunny Spain - and never had a plant etiolate in any circumstance, wherever they had come from. In fact I have only ever seen pics of an etiolated plant.
If you are disagreeing that that is my experience then we have nothing more to say.

Actually, artificial lighting is always very dim compared to the sun. The sun gives a light intensity of 100,000 lux - 1 lumen per metre squared = 1 lux. Even behind a window on a dull day your plants can easily get 10,000 lux. Go look up the output in lumens of a fluorescent tube - it is not a lot!!
I have a Metal halide 400W tube - an efficient light source when quoted in lumens per watt - to the eye it appears totally dazzling, especially at night - but the eye has a naturally variable aperture and is a very poor judge indeed of light intensity. With my light meter the incident light intensity of that tube on a plant is found to be a whole LOT less than daylight on a cloudy day.

Sorry guys, but I feel that contributors to this thread are stating as fact what they THINK might be the case - or what they have READ (LOL). Or what they are guessing - or hoping.

NOT what they have FOUND to be the case from their personal experience.

I NEVER state anything that I have not FOUND to be the case from my extensive personal experience.

Regards
Fly - OK one old and REALLY annoying bastard.

Etiolation isnt the wavy growth pattern, it refers to thinner than normal growth on plants grown in too little, or the wrong spectrum of light. They only get wavy if the conditions are inconstant.
Cacti that are straight and normal looking can be etiolated and just be skinnier than their potential.
You assume no one is speaking from experience, so heres some experience. I got a T. scopulicola from the UK which had been grown under lights. It was a nice cactus, an even green, consistent width, I was pleased with it. It was 4 cm wide. I grew it under lights, it grew well, nice color, consistent width, put on lots of growth- all 4 cm wide. I cloned it and put a clone in the sun.
Kabammm! the clone bulked out to 9.5 cm (thats nearly six times the mass per inch of stem). That first clone is now on its way to a full meter tall, nice consistent (darker) green, nice consistent (fatter) width, and in a few years the fuckin' bastard will weigh more than me

So even if you had beautiful and worthwhile cacti its quite likely they were etiolated, as defined by growth significantly lower in diameter than the specimens potential and caused by bad or low light.

^

What I do to avoid etiolation (which I have had problems with before) is to firstly stop watering my cacti when the weather gets chilly and the days get short. This is usually around October. I did just water my Pedros and I will probably water them only once more for the year.

Once it gets decently cold and frost threatens to hurt my plants I will put them in the garage where they get no light and will be cold enough to go dormant but warm enough to be comfortable. If it gets freezing or below then I'll bring my plants inside and put them downstairs in a cool room (no windows, no light). This usually happens after they've already stopped growing.

From my understanding it is better to keep them in total darkness for dormancy instead of giving them small amounts of light (which could cause etiolation).

No water and no light