I don't think there should be any problem w/ clear cups. I use them.

The only problem I had was with them falling over. Just don't let them get too tall and be sure to cut drainage holes in the cup.

I always use the clear cups. They have all colors of clear and it doesnt seem to matter. I start my tomatoes and peppers in little greenhouse thingys then plop the peat pellet into a cup. Just make sure to put drainage holes in the bottom. I use half potting mix and half perlite in the cups. Next step is into the garden. You cam write on the clear cups w sharpie then wipe off w alcohol when you want to re use the cups.

Hello everyone! Thank you so very much for the input. Bugman Ronn built me a conservatory that is just been outfitted with lights this season, and boy, have I gone overboard! Will send pics soon. Carol, Sherry, Jasmine, thank you for the responses. Would love to see and hear more what you are up to! Silvia. Wow. As always, your plants are gorgeous! Looking forward to pics of you garden too....

Thank you Elizabeth, I am looking forward to see the pictures of the new built conservatory, sounds great! and I am sure you will get a good use of it.

I have been eating from my garden every day, after the frosts I have carrots, beets, lettuces, kale, spinach, a lot of onions that I am using some as green, colorful and tasty radishes.

I have a good flower show indoors, the violets are blooming.:)

Silvia

I wouldn't use clear containers because it sends the wrong signal to the plant. I've always just grown orchids in clear pots. I realize they're just for seedlings, but roots need darkness or they get confused and can also be damaged by the light. When the roots have problems the entire plant can as well. Here's an article I found that explains it better than I can.

Soil Roots and Darkness

When roots naturally grow below the soil surface, nearby light signals they are headed the wrong way. Like stems, roots contain growth-directing hormones known as auxins, which tell them which way to grow. In the same way that upper growth on plants bends toward well-lit windows, roots naturally grow away from light. They seek darkness and protective moisture instead. In transparent pots, these roots avoid light-penetrated areas of soil. Forced into high-light areas, light-sensitive roots recoil and slow or stop growth. When light dries soil out, tender root tips can suffer. The rest of the article - http://homeguides.sfgate.com/potted-plants-grow-better-inside-transparent-nontransparent-pots-104339.html

Here's a bunch of passiflora cuttings I grew in cups outside..Sun didn't bother their roots any :)

They grew up to be big healthy plants

Yeah ... and they look fabulous, but scientifically speaking it's not as good for the plants as a dark pot. The nursery industry doesn't use clear plastic and it seems like there's a lot more clear plastic available to make pots than there is dark. The only clear pots I ever run into are for orchids or epiphytes.

I have a hard enough time getting most things to root and sprout and grow so I avoid anything that might be a deterrent. I guess hardier plants can handle it better ... not sure ... I've never experimented with clear vs dark plastic.

Your passion vines certainly look healthy and happy. You are going to have some happy caterpillars.

Beautiful Jasmine! Thank you Sharon, that is a very interesting article. I ended up using some of both - clear and red - and don't see any difference but on the other hand why add a variable?