You could alter the plant growth to go where ever you want.
Large root mass promotes stronger plant that grows faster.
If you flower it soon and use certain fertilizers you could get a big plant with small root mass, that will grow pretty slow compared to a plant with more roots, but will not rootbound and will do just as fine.
I grow in soil, with 25 liters (a bit over 6 galons if I recall correctly) for each plant, growing the plants around 1.5 meter high.
More space is much better than not enough space.
Healthy plants will take a lot of water as well. using 5 galons rez. with a max of 4 galon of solution will need a lot of refilling.
I, myself, would rather use a big reservoir and attend to it less. If i got a galon of root mass I would like to get around 10 galons of solution at least. That way I can only change the water once a few weeks and not every 3-4 days.
However, I never grew aeroponics, or DWC.
I find it way too exhausting to do all that work and monitoring all thoes little details.
This is my 5th run, and I'm just trying hydro using coco\perlite mix.
Hydro is way less forgiving than soil, but it grows much much faster. Using coco\perlite I get a lot of benifits:
It doesn't requier ANY different pots or setup than soil plant, and thoes are way easier to obtain.
It is hydro, it grows fast and it have just about the same qualities.
I have no need to monitor any temperature at the roots, at the reservoir (I manually feed my plants once every 3-4 days because I use pretty big pots compared to the root mass) and I don't have to buy all thoes fancy meters.
I don't check my EC and PPM, although I would like to. However, I got a hard water formula to use with my tap water and a chart for how much to fertilize and it works like a charm.
I don't need no air pump, no air stones, no water pump and drippers (altought I have them at hand to water my plants if I need to go away for over 4 days), no reservoir and no nothing.
I don't need the space to contain all that gear.
I have no issues with any algea or such things as usually bother other hydro growers using different method.
That why I like my coco\perlite. Everyone have a different setup and different needs. However, for a beginner, I would recommand a coco grow as it requiers WAY less initial investment.
You would only need to buy:
Lights, vents, reflective material (and a hood for the light, if you got the money an air cooled one is preffered), temperature and humidity meter. Thoes you need no meter how you grow.
For coco you will need:
Coco. I like coco and perlite mix, 50\50. some use coco coir and all sort of things, I only have that mix available.
Pots. the same as soil ones, nothing special. I use clear plastic cups with holes cut in the bottom for my new plants as they veg. I can see how many roots form and bound and know when to move them.
Catch trays for the pots. Some like it, some rather expose of the drainage as it contains salt buildups and such. I like the catch trays as I don't have a way to put away the excess water.
Digital PH meter. don't use the strips or the solutions and all that, its just too much work. A cheap one from hong kong bought from eBay is just fine. (and if it doesn't work well they DO replace it)
PH down solution to lower the PH and baking soda for PH up. You can use vinegar, lemon juice and all sorts of other things to lower PH but the solution oriented for plants is really cheap and works better.
Hydro fertilizers. Some manufactures got ones specialized for coco, and some have hard water and soft water versions.
And you can spend more money on:
A fan to push air around your room. It helps alot lowering humidity, keeping the temps at bay and promotes stronger stems and overall healthier plants. You can go aroud this one if you use a strong vent for your exhaust and it will cause enough movement. I always rather use a seperate fan and find it very important.
Reservoir+ water pump+ pipes+ drippers+ small water pump to circulate the solution. That if you want to use auto-watering.
EC\PPM meter. With one you can push more fertilizers and yet don't burn the plant. It will help it grow faster and you can keep track of whatever the plant needs to use on your next run.
Compare that to your initial investment in DWC, aeroponics or whatever and decide what you rather have.
Almost all of the things you will buy for a coco grow can be used for any other hydro growing method.
I don't say its better, I say its easier and costs less and I would myself rather go that way for my FIRST grow.
Good luck with whatever you choose.
