Correct light?
Correct light?
What should i do to get them bigger/thicker at the bottom? Light from the side and turn them around? Today they are under HPS 200W, they will move out to the greenhouse in 2-3 weeks.
Re: Correct light?
They really won't get much bigger at the bottom, if at all. About the only thing you can do is to start new cuttings. They look pretty good as they are now though.
Re: Correct light?
They look perfectly normal to me. Cacti are usually thinner at the base when grown from seed and get thicker and spinier as they get taller and more robust. If they are same width at the base it usually indicates they were originally rooted cuttings from a more mature plant rather than grown from seed.
The time to worry is when they are thinner at the top than at the base since that usually indicates they are etiolating through lack of light.
Scroll down to the young Pachycereus at the bottom of this link.
http://www.llifle.com/Encyclopedia/CACT ... s_pringlei
The time to worry is when they are thinner at the top than at the base since that usually indicates they are etiolating through lack of light.
Scroll down to the young Pachycereus at the bottom of this link.
http://www.llifle.com/Encyclopedia/CACT ... s_pringlei
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greenknight
- Posts: 4818
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- Location: SW Washington State zone 8b
Re: Correct light?
Right, the bottom part won't grow any more. The grooves between the ribs may flatten out eventually, but they won't grow any thicker.
Spence 
Re: Correct light?
Would this cacti bend against the light like other plants? I have some that are bended, but i think its bending away from the light?
Re: Correct light?
It is a bit crooked, but I don't think it's because it is leaning away from the light. You could straighten it up whenever you repot it, though.
Re: Correct light?
Strange to say I have been told of several cases like that recently of cacti bending away from the light, often on windowsills, but have not been able to locate any satisfactory explanation yet. When they were turned to straighten them up they eventually bent away from the window light again.
Normally light retards growth on the light side and the side in shadow grows slightly faster, causing the plant to bend towards the light (positive phototrophism). However things like roots usually show negative phototropism and move away from the light, but not usually cactus stems.
https://www.youtube.com/watch?v=2A_LKrLlhxE
Interesting in that video is the mention of light colour on the auxins. Could it possibly be that the plant is receiving more of a certain colour of artificial auxin retarding light from within the room than the full spectrum of daylight from outside?
Normally light retards growth on the light side and the side in shadow grows slightly faster, causing the plant to bend towards the light (positive phototrophism). However things like roots usually show negative phototropism and move away from the light, but not usually cactus stems.
https://www.youtube.com/watch?v=2A_LKrLlhxE
Interesting in that video is the mention of light colour on the auxins. Could it possibly be that the plant is receiving more of a certain colour of artificial auxin retarding light from within the room than the full spectrum of daylight from outside?