in a hydroponic set up you can grow a full plant with a 6x6 inch cube or minimum 2-3 gallon container, all the roots need is a constant supply of air and enough water to feed off of. i used a 12x8x6 inches container for mine and have not had problems because of it. i would suggest scrog and lst to keep the plants low. you can do autoflowers in hydro no problem. i have done 2 harvests of such and they are very easy. if you have enough space i would say look up a rotary garden (youtube omega garden) that is the best way to get the most of your space/lighting/plants. roots competing for food can be a problem so if it is possible then put them each in there own individual containers.
main problems of hydro are - needs constant attention to ph and nutrient levels. especially as a seedling. needs constant air supply (constant power supply) if the power does go out take the plant out of the water or at least raise 50% of the roots above the water line.
ph will have to be checked daily and you have to de-chlorinate the water or risk losing the plants and the nutrients. leave the water sitting outside to let the chlorine evaporate for 24 hours prior to change.
with hydro you get the fastest growing/flowering time. i have found that they dont tend to be as hard (stem/stock wise) and might need support to stand. lst/scrog negates this though.
in a scrog/lst make sure you attach it to the lid of the container and not the surrounding area as when you lift the top of the container off for water changes, root inspections, ph testing you will have to move the side supports.
for ph up i recommend potassium silicate as it improves the cellular structure of the plant and helps it maintain a healthy stock. takes 10-20 minutes before you can take an acurate reading of the ph levels though and always add ph up first to help set a good base when adding nutrients.
with lst you will set the height of the plant and how high it will grow. with this factor under control you will be able grow a large, full plant in a 3 foot high space no problem ( 6 inches for container, 12 inches for plant growth, 18 inches remaining for airflow and light fixture. led/fluorescent would be preferable as the lighting spectrums can be exact and help with both stages of growth. please get at least a 3w chipset if you buy an led, this will give it enough power and penetration to get the most from your plant.
adding a uvb (reptile) bulb you can increase the trichome growth as trichomes absord the uv to protect the plant. DO NOT put the uvb bulb to close or you will burn the plant. 1 bulb per plant is more then sufficient ( i used 1 for 2 plants)
keep constant air flow and try not to over feed them. less is more sometimes.
if you need ventilation look up DIY Filters on the general growing page.
Its pretty simple, oh and ph should stay between 5.5-6.5. i would also recommend ramping up/down the lighting schedule when going into flowering. going from 18/6 - 17/7 - 16/8 -15/9 etc etc.... as a straight over switch from 18/6 - 12/12 can cause stress in the starch production and feeding cycles as plants can "remember lighting cycles" this can take place over 1-2 weeks no problem as that is how long most plants take to switch from veg to flower.
anyways, Good luck T
