how long is too long in beer cups?

[FirstTracks]

How long, in your experience, can I keep a seedling/plant in a small cup like this ~4" tall before the tap root hits and I stunt the plant?

Background:

I've grown autos before but could use some advice, and I know there are some very knowledgeable people around here.

In less than a week (hopefully) I'll be starting a bunch of autos outside.

The mix will be made up of: SGS Pinkbud, SGS AF Mix #1, Sour 60, and maybe a couple Roadrunners.

The plan was to start these in 16oz plastic cups with appropriate drainage holes poked in.

Soil Mix would be as light as possible, possibly pure perlite, 50/50 perlite/coco, or maybe just a peat moss/perlite mix.

So the clear cup pictured is like the ones I have, but i can use the red beer cup style too.

I like the clear ones better for root mass visibility, taking up less are per cup in my trays, and sharing approximately the same depth as the slightly larger red beer cups


I was hoping to make it 7 days or so, or up to the 2nd or 3rd node preferably, before transplanting to dug holes.

2 liter containers have been considered, but small container size means easier bulk transportation and more per starting area.

 

[Ptone]

I think you'd be alright for 7 days. Also may I recommend using clear cups and sticking them in red cups. That way you can check the roots but you do not expose them to light.

 

[yesum]

I used 18 oz. cups and vegged for 5 weeks till transplanting to final pots. Filled the cup up to the brim with soil and perlite mix, did not notice a bound up root ball or stunting of plant. If I used a larger pot to veg, the plant would likely be some bigger, but I have space limits.

Break up the root ball a little when you transplant, in case there is some binding in it.

 

[Donald Trump]

you'll be fine.

 

[habeeb]

well depends on some things

as someone said, if you want the clear cups, put them in the other cups, but to me this is pointless and a waste of time.. which could easily be solved by doing 2 runs, and adjusting time to see what root mass there is at the given time..

now, if there is regular seed, I would wait for them to sex. no point transplanting, to only waste "soil" and work for males. this is usually 2 weeks and fine for the cups, would be better if they were a little bigger,which you might want to check out plant it earth.com , as there pot selection is great in small pots, they have some that are a little bigger then solo cups and would imagine people should replace the solos for these pots, or they have a size that is same as a solo which I use to use all the time, but like the one step up as it would mean more rootmass

coco will get a bigger plant, and the root mass would be more, and coco seems to tolerate smaller pots better then peat. but coco and peat are a little different, and would choose different nutes depending on going coco or peat, or a mix.

for your question though, I would be hard pressed to see a stunted plant by day 7, I mean a week in is not that long, also depends on lighting, as if your nuking them with a 1k, then they will need transplanted sooner then a floro setup or smaller light...

hard to say man, as so many variables, but I sex autos in the solo cup size, but I don't need yield so...

 

[FirstTracks]

Thanks for all the input so far everybody!
really appreciate it.

Just to clarify a couple things..

>These will be packed in tight in a deep tray, the cups themselves buried in a bed of peat possibly.

>Specifically asking about an Autoflowering strain being stunted. From what I've read, and my limited experiences growing them, The first 2-3 weeks of growth are critical to the final size of the plant.

Really, since the entire growth cycle has to take place in such a limited time, any slowing down of growth will result in a smaller final plant.

>I'm not too worried about sexing in the cups. IME, this will take from 15-24 days withthe average auto. Maybe these, being a newer generation of autos, are faster, but I've found 14-18 days for males, 16-24 days for females on average to show sex.

These are going to be for personal, so some males will get left in. Really, I'm going to sex them after they're already in holes. Just making holes 10-20 gallons each and putting around 10-15 successfully started seedlings per hole. I have a good amount of seeds, so I can always cull if space becomes an issue.

Again, thanks and please keep those opinions coming

 

[RoomRaider]

They will be fine in the cups till sexing. 21-30 days. Very few actually do get rootbound, and its not a serious case at all. You can easily massage the bottom a little, breaking the roots up gently, so that after transplanting they grow into the medium better.

The first 3 weeks are important. But they still grow roots, and grow upwards well into flower. I don't really think they stop growing..... they just get chopped.

I've always wanted to harvest the main colas and let the bottom go much longer, see if they really do keep growing, but space is a premium and the new generation trumps experimentation.