Will (3) Sativa Plants in 7-ga. Fabric Pots fit into this Greenhouse for an April-October grow??

Getting set to pop Ethiopian sativa seeds in Root Riot cubes. Planning on starting with the seeds on April 11 and ending late Sept- early Oct. Three plants. Do you think they'll outgrow this 6x8x8 greenhouse? Thanks for your horticultural opinions. I've used clones for the last 5-seasons, this will be my first using seeds.
Also, does the tap root need cutting or just let it grow? Thanks!

why in the world would you cut a tap root?it's not a bonsai tree, and you aren't trying to achieve the same goal.
a 6x8 greenhouse ought to be plenty big for three plants, i run 6 in a 4x7 grow room, and could cram a t least one more in if i wanted to have to drag it out of the room to have room to work.
so even if they get huge, the only problem might be height, which is fairly easy to deal with, tie them down if they get too high

Thnx for the suggestion. I saw "cutting the tap root" on the instructions to my SuperSprouter and didn't know if they were talking about canab.
Last season I tied mine down through 2x4 wire circle fencing. All are on 18" plywood circles with casters. I can sit on a Harbor Freight caster-seat and spin the plants to water them with a siphonx.
See the shape on them? LST'd as low as I could bend them early-on. I didn't keep enough air moving at the bottom fo the plants, and got brown-rot on some bottom branches.
This coming season. I plan dropping wet-paper towel, day-soaked, seeds into root riots on April 1st, instead of April 11. I have my SuperSprouter wired. The temp stays 78-degrees 24/7. I think I'll need 3-weeks to get them from root cubes to solo cups?
What I would like to do this year is manifold the plants. The bigger and taller the colas the better. I'll use plastic yo-yo hooks to catch the weight. Less foliage to restrict air movement and less trimming later.
What do you think about manifolding plants? I use NextLights Mega LED with a 7x7 veg and 5x5 flower. (shown)
http://www.growweedeasy.com/manifold#intro-main-lining-manifold
What's your opinion on manifolding (3) plants in my 50" x 50" x 80h tent, on an 18/6 schedule, until I can take them out to the GH? The sun's demise begins on July 22, 2018 in my area (13:59min).
After that I need to know what day of the month to take them of the tent's18/6 that's been reduced in light ratio, by 17/7, 16/8, 15/9, to 14/10, 13/11, and 12/12. Taking them out to the GH somewhere around 13/11, is probably safe not to have them re-veg?
I'll be asking farmer some questions on the timing in our area, but he's a clone guy and told me that seed stock grows a totally different plant structure than a clone does. Is he right about that?
And lastly, can seed stock be topped for a clone, just like a clone can be cloned? Farmer might have said that seed stock can't be topped and clone-sprouted?

sure you can take clones off of seed grown plants, someone had to take the first one off of something.
most of the difference between a clone and a seed plant isn't visible on the outside. clones don't have a tap root, they have a big fiberous mass of roots. seed plants roots stretch out as well, but not as much. i've grown plenty of plants from both, and i've never noticed any consistent difference between them physically.

Roger A. Shrubber said:

sure you can take clones off of seed grown plants, someone had to take the first one off of something.

Click to expand...

!!
Cool man... great to get real advice. Thanks!

I've changed my germ-plans to the drop or float system:
"I'm glad to hear you plan on growing some gals from seed, but I disagree with your proposed method of germination, in terms of paper towels and root riot cubes. When I do a seed run, I dump my seeds into a shot glass of tap water for 24 - 36 hours. Those seeds that drop to the bottom are viable. Those that continue floating are usually not. Once the hull cracks and the sprout starts peeking out, I then use a 20 oz. pre-drilled Styrofoam cup, filled with Kellogg's (raised-bed) that has been totally drenched with water -- and place my seed about 1/6" - 1/4" under the surface. I don't add any water until after the seedling has broken through to the surface. Over watering before then is fatal. During the first 7-10 days, the majority of the growth is in the roots, way before you see the first bit of green. My success rate is close to 100%.
When using the paper towel method, removing the germinated seeds can result in damaged feeder roots that extend from the tap root, as they often start growing into the paper towel. Do not trim off the tap root. But, to each his own." - farmer

manifolding is cool, but be aware that it slows the plants down a little and you have to give it extra veg time to catch up.
i prefer lst myself, but to each their own.
these girls just went in the flower tent. they've been tied down for weeks, and just got a good pruning before i flipped them. i'll keep tying them down as they stretch, and prune them again in about three weeks, then maybe about a month after that, maybe not, depends on how they look then

Yes, I lst my plants as well, but this season I'd like to try manifolding, because I like the larger colas that need less trimming at harvest, and I'd like to deal with less foliage and maybe adding to the overall air circulation at the floor upward - better controlling bud-rot in those 4th thru 11th month sativa grows. Here's the info again: http://www.growweedeasy.com/manifold#intro-main-lining-manifold
How many extra weeks should I begin seed sprouting for extra-vegging with manifolding? I can start anytime. Again, I'm thinking that April 1 was soon enough for an 82-day bloom ending in Sept/Oct., but now maybe late March, I'll soak the seeds and solo cup them as suggested by farmer.
I may have answered my on questions here. Thanks for posting the lst plants. They send up bud-shoots too.

This is the original version, the later version is split evenly at the center with an 1/8" stem nub left in place. The even-split manifold is wider and more bud abundant. http://www.growweedeasy.com/manifold#intro-main-lining-manifold