When should I switch to a larger container?

I've got 9 plants that have been above the surface now for 5 days. They are all about the same size above the soil. Underneath the soil 2 of their roots have gone to the side and since I'm using clear Solo Cups I can see that their roots are only about an inch away from hitting the bottom of the cup. I would assume that the others roots about the same distance from the bottom.

Is it time to move them into a larger container? I would like to keep them in the solo cups as long as possible without slowing growth too much.

Thanks!

I usually start my seedlings in soft drink cups then let them grow for about 2 weeks and transplant into 5 gallon pots. in your case I would transplant asap, the clear cups will stunt the growth of your plant if the light hits the roots.

two weeks in 16 oz party cups blue or red into one gallon its easier for me to control the watering ,three weeks later we move into the containers we will finish inn

Usualy i would wait to to 3 weeks but if i were you i would do it NOW. Clear containers are deff no good. thats why roots are under ground bro they hate the light. rule of thumb for now on tho, now you know.

Hmmm. my first reply didn't post for some reason. Anyways, thanks for the headsup with the clear cup thing. I totally didn't even think of that, but it makes sense. Live and learn. Only question though is if the plant roots hate the light so much then why would they grow towards it?? Genuinely curious

i have seen tap roots and root systems grow up because they follow the path with less resistance and where all the water is, and you water the top of the soil, and as soon as they are out of the dirt for a day or 2 they die.

it's important to know what way you are growing, mostly what type of light, or are you outside, i'm assuming you are not, but a general rule of thumb is once a month during vege, especially if outside, but if you are using cfls or a low wattage HID,hps,mh, etc.
i prefer to have a somewhat formed rootball, not only does that assist in the actual transpanting, but it ensures that the plant is less likely to expereince transplant shock, another thing that i like to do, contrary to some beliefs, is if the roots are somewhat rootbound alot of people like to slice vertically down the rootball to encourage horizontal root growth, i've down this in an experiment and found that it slows growth, and in the "uncut" clone the plant actually had a more developed rootball than the "cut" clone....
anyways i seem to have digressed a bit

I've covered the cups in duct tape for now since I cannot transplant them tonight and lights are about to go off anyways, but I will tomorrow.

Thanks for all the help guys! I will say that this is my first grow and I've had many questions along the way and no doubt have committed more than a few errors, but everyone on this forum has been extremely helpful and I really appreciate it!

Hey no problem chip, if you have any thing that a you dont want to post in a thread just pm me bro. check out my balcony grow its not a journal just an album on my profile. good luck and stay green.

roots grow down towards the water, not up towards the light

I'm somewhat surprised that no one has mentioned that "plastic" start containers are not the first choice for your girls. Nor is the transpanting process a good thing. When I start a new strain, it always is a dry seed into a 3" "peat or coconut" cup, filled with a good starting mix. When they get their 3 set of leaves, they go into the final medium, cup and all, NO transplant shock! If you want the MOST from your girls, give them a smooth transition from seed to final container.
Good luck & good grow.......BB

You just gotta learn from experience when the plant looks like it's being stunted. From my experience I've found that transplanting twice, once from the solo cup into a quart ish size container and a second time to your 3 or 5 gallon container helps the plant grow better and faster.

No one mentioned it yet but you can actually harvest a plant from start to finish in a solo cup... stunted growth doesn't mean death. There's was a solo cup competition going on to see what ppl could do. It looks funny seeing a small plant with one cola at harvest but its possible. The plants fill out whatever container they grow in, typically for most hybrid indica/sativa you can presume to have 1ft of growth per 1gallon of soil. Solo cup or peat pot... still growing in soil... plastic doesn't stunt growth. Deuces.