Roots and light - using clear 'party cups'

Hey all, 
 
Got some clear cups in use - el cheapo 'party cups' - and can see masses of roots growing around the inside of them, up against the clear walls. Nice and healthy looking white, plants are happy, and there're no immediate issues from what I can see, but...
 
... will the light getting to the roots cause an issue long term?
 
Main problem I can see will be bacterial growth in the soil - not sure about the roots themselves being damaged.
 
How quickly should I get some little 'skirts' made for them to cover the clear sides? Any experiences with this sort of thing, either the roots becoming a problem or the making of covers for the sides? 
 
(Can't seem to find solo cups in New Zealand, even at the larger suppliers of such things - anyone know of anywhere? Or equivalents?)
 
Cheers in advance!
 
 - Dave.
 
 
 

I've grown tons of plants in clear cups, they turned out fine. I only stepped up to the red solo cups/dixie cups because the clear plastic ones I had were too brittle. I wouldn't worry about it they will grow perfectly fine. It's a good way to see how your root system is developing, soil moisture, and how your soil mixture drains. Once your plants have a good canopy the cups will be in the shadow anyways.

I grew in clear cups last year without a problem. The only reason I'm using red cups this year is its easer to see what plant I have with my black marker when I mark the cups....

Many thanks - feel better about it now!
 
Both great answers, thank you.