It is the clear, non-opaque, cups that is the basic problem - many discussions here about the problems caused for the roots - and the color of the cups will affect how and what part of the light spectrum affects them.

Roots are negative phototropic - exposure to light burns the epidermis of them. So neither blue nor pink is beneficial but the blue spectrum exposure is somewhat better tolerated than the rink/red spectrum is by roots. Ideally one doesn't use any clear cups regardless of color.

Dave

I agree with Dave. I tried 3 or 4 clear cups one year because they were free. Free or not I'll never use them again. The roots do not like the transmission of light to them. The ones in the clear cups from the same variety, seeded at the same time as the ones in the opaque cups ended up losers and being tossed out. The ones in the non see through opaque cups did very well.

Lesson learned!! free or not I will not plant in any clear container

its odd because i follow praxxus alot and he does very well in clear or slightly opaque clear cups. i only use the blue colored cups though and get great results with anything i plant in them.

Here is a link that might be useful: TheItalian Garden

Have no idea who praxxus is but like some others, perhaps he just doesn't know any better. Which is odd as any experienced nursery grower knows and there is plenty of science-based info about it available on the web for the layman.

Dave

Hi.. thanks everyone for the feedback. I guess I will have to be more careful with the tranparent cups.

I had seen Ray (from the praxxus channel) do this but also thought that it was probably ok b/c soil blocks are an acceptable means of growing seedlings as well and in that the root are pretty open to air as well. I guess you keep those pretty close together and don't let it too much light.

It is simple enough for me to just place my cups in another opaque cup... so I may do that. Waste of cups but oh well you live and you learn.