The Garden Community for Garden Lovers



caution; If you have time to spend please read IN THE SHADE In my questions first, before reading this, as this is just on observable phenomenon as I see it. Trawling through blogs and questions on GoY I came across a question on shaded grass seed and that got me to thinking again on the effect of light on plants: I have been growing for some time now, epiphyte cactus, and for all I know xerophyte cactus: as the acquisition by devious means of the plants I get; have to hold to certain parameters such as, strange, different, not normal (to me) and in general terms, just plane odd, or have about them a, can I do it aspect; my failure rate is high, but then again so is my knowledge rate as I try different ways of doing things, with success and failure all contributing to the knowledge base on which I make only spasmodic notes; and finding them in my filing system many moons later after my obsessive infatuation has passed to another plant.
This winter’s below freezing temperatures have caused me to reduce the amount of cacti I have produced due to the heating costs of the green house and the amount of room available for in-house safe keeping during the cold spell, never the less the in-house plants have raised some interesting questions during their period of supposed dormancy the advice of reduce watering in the winter, in cacti terms let soil dry out before further water is added, resulted for me in a Euphorbia Caput Medusae going into hyper etiolation as did a Euphorbia Enopla which demanded water to sustain the rapid growth further resulting in a dying off; admittedly the etiolation was caused perhaps by the very low light level in the bed room where they were, and perhaps the humidity level had something to do with it, being extremely low. So why the sudden eruption of growth in a dormant period; the E/Enopla is now starting to flower below the etiolating point “Why is this”? ( I am asking myself this question, rather than the reader, but if you feel like responding please do so ) Further, on epiphyte cacti again in the dormancy period but observable also in normal growth periods, I have noticed that some cacti exhibit what seems to be a reduced effect of etiolation with the plant showing a light green (almost lemon green) colour in its body as set against the preceding growth and a clustering of white spines (which on later development turn brown) attempting to turn the columnar growth up towards the main light source, on the first noticing of this I assumed it was due to the shortage of sunlight in this country but since that time I have noticed the same effect in high sunlight areas such as the Cannaries of all the reading on cacti that I have done I have never read of this occurrence perhaps some-one out there may have an answer.

More blog posts by smileamyl

Previous post: UGH BUG




All I know about Cati/Cactus is that where they come from is very hot in the day and very very cold at night, so don't know if this helps you on why they grow in the dormant cold period. Hywel might understand this better.

21 Jan, 2011


Oh, heck !!! went and read the question as advised, backwards and forwards, read and re-read this.
One thing I do know is that for some reason my own cacti have grown more this winter than any other in a long time, I never alter there positions, apart from picking them up for cleaning purposes. I also haven`t fed or watered them, in fact its a wonder the poor things survive but saying that they are of a good age, so guess they like living where they are.
Will be keeping an eye out for the answers tho......

21 Jan, 2011


I hope I can answer ...

What causes etiolation in all plants is too little light. Some like less than others but even they will become etiolated if the light is too dim for them.

Cacti need a lot of light, so it's easy for them to become etiolated in the winter. However, I keep mine as dry as possible and as cool as possible, so that they don't want to grow. That way they don't become etiolated.

I do have some in warm shady rooms,
but because I keep them very dry, and near the windows where it is coolest, they don't want to grow.

I give them no water at all from November to March. Then they get a good soaking. After that no more at all, until they go out to their summer shelter in April/May.

22 Jan, 2011


Cor blimey, the knowledge on here has no bounds. I have never grown cacti, but I find this fascinating, I don't mean this to be sarcastic , but reading this several times over nearly gave me a head ache. LOL. A very good explanation Hywel.

22 Jan, 2011


Thank you littlelegs. I was hoping it made sense :o)

22 Jan, 2011


I now understand it better now Hywel thanks I knew you would know :o)))

22 Jan, 2011


Thanks Sixpence :o)

22 Jan, 2011


:o)) your welcome Hywel.

22 Jan, 2011


etiolation is indeed due to low light levels as the growth hormone Indol acetic acid[IAA] is high. In bright light the levels of IAA is reduced . Plants then have more IAA in the shaded side and those cells elongate more than the ones on the light side. IAA 'softens' the cell wall so water can be taken on board by the cells and grow in size. As the cells are attached to each other the result is a curve towards the light.

If stressed many plants try to flower and set seed before death. Could this account for your plants?

As for the grass under the trampoline, if the tramploine has a black mesh like ours the heat absorbed by the ground is quite a bit hotter and we find the grass scorches.

22 Jan, 2011


Indol acetic acid that's a new one on me. must delve into it: though many years ago I did make vinegar with acetic acid and sell it. thanks every one

23 Jan, 2011


proper vinegar is acetic acid. there is a big acetic acid plant on the out skirts of Hull.

24 Jan, 2011


Vinegar is a dilution of acetic acid to taste adding gravy browning makes it look like malt vinegar (bin there dunit).

24 Jan, 2011

Add a comment

Recent posts by smileamyl

Members who like this blog

  • Gardening with friends since
    10 Oct, 2008