Agree. Much better to just avoid the clear cups in the first place but wrap the cups now to prevent further light exposure. Since they were already leggy I hope you buried all that stem when transplanting them.

Dave

Or try blue painters tape around the body of the cup to shade the roots. Solved!

I have been using clear cups to start my transplants for the garden for 30 years. I have never noticed any ill effects from doing that. I love them because I can see if the roots need water through the cup and to see the root growth. I get huge amounts of tomatoes, peppers and my rose cuttings like them, too.

So my opinion is to use clear cups, and enjoy the show.

Rebecca

I have heard conflicting views about growing seedlings in clear plastic cups or glass jars( w/drainage). I root a lot of cuttings in tall glasses, all the time. But somehow I don't like using clear cups for growing seedlings in them.

Sey

One need only understand the nature of roots and that they are negatively phototropic (stressed and damaged by exposure to light) to understand the disadvantages of using clear containers. In addition to the research article linked in the original post, there is ample research available to support the argument against doing it.

Of course one can always choose to ignore the research and rely on their anecdotal experience only but what is convenient for the gardener isn't always what is best for the plants.

Dave

Thanks, I appreciate your help, and
since there where good root growth already, I re-potted them. Dave,
yes I did bury the stems deep. That is the reason in using the tall
clear cups.

Jeannie

I think what Dave has said makes sense to me . But I am not sure as to the extent of the effects on plants. The other thing is that we are talking about indoor, under lights , not outdoors under direct sun.

Sey

Sey, those were my thoughts exactly... I just didn't know how to say them. :)

Rebecca

I'm curious as to why you'd think that makes any difference. Light is light and only varies in spectrum and intensity and the article linked address both UV and non-UV light spectrums. Research studies, including the one linked above, make it clear that exposure of roots to any degree of light

their growth, physiology and adaptive stress responses are light-sensitive and affected

light exposure increases algae growth among and on the roots leading to rootlet suffocation

that their ability to transmit proteins and auxins is compromised

that their sensitivity to salinity is altered negatively (root halotropism)

that the plants ability to photosythesize energy is compromised

stressing roots with light is modifying not only root responses to diverse stresses but also the overall physiology of such seedlings (Jeannies quote above).

Like I said, the choice is yours but since there is nothing to be gained by exposing the roots to light and potential for damage to be caused, why do it when it is unnecessary?

Dave

Dave, personally I do it for one reason... So I can see the roots so I don't over- water my plants. Without clear cups, I drown them every time! I don't have a single house plant for that very reason. I just can't gauge that finger in the dirt trick that every one else seems to be able to use to know when to stop or when to water again. I guess I am watering "dyslecsick"! :)