Why is my plant all stringy

I have already finished this grow I used a 400 watt light in a 5 x5 tent the plants from the ground to top were nearly 6 foot tall and I had about 15 in the room I no I did something wrong because my dry weight was a little more then 5 oz I'll try and put pics up soon so u can c but if u have anything off the top of your head for reason let me no the light was never more then 14 from the tops of te plants under it

You vegged too long and used a light that is too weak for that sized space.

I did a 2 foot veg on them and then flowered them but even the biggest top I had only weighed like 2 gs

My answer is the same

So how tall should I veg and iv also hurd for that amount of space I should have a min of a 600 watt light but is it posable to make the 400 work and if so how

Put less plants in, and try flowering at 12 inches.

Ideally you want 50 watts per square foot. 5 times 5 times 50 = 1250 watts. Even a 600 would be too small to use the full space. For your 400 plan on 6 plants max.

And they should be smaller and bushy and more yeald ? Could the size of the puts have something to do with it also?

A lot has to do with the genetics, but generally speaking the shorter you keep your plant the more light will get to all the bud sites and produce better weed. Pot size is a factor but it sounds to me like you just need to flower earlier.

Ok well I used 1 gal pots next time I'll go with six in 5 gal pots flower at 12 inches and prob tye them down also would that be a good basic set up and I'll prob grabe my friends advance nutrens and I'll prob get some clones from the clinic do u think that's a good set up

5 gallons seems a bit overkill to me but I'm a hydro guy, hopefully a soil person will recommend a good size for ya.

Iv done hydro and dwc I got the best with the dwc but soil was right up there for me but I figger better more dirt then less u would think

general rule of thumb when using soil, 1 gallon for every month of growth. if you veg for six weeks and flower for eight, then a 3.5-4 gallon container would be ideal.

TWB Hello, I am by no means an weedspert but I have looked into this.Via RIU posts as well as well respected grow lit. and in the end insufficient lighting (U figured that 1 out 4 yourself ) I am also learning shoulda got the 600w hps (Best in class based on overall efficiency ) I have also read that the 400w CMH although putting out less total, has the best in class useful spectrum. I have also seen a single plant put out that 4-5o from a 1000w hps??? 2 names come 2 mind Ridleme and Hobbes - I personally like aspects from both of their styles-I am certain there are many others I also like Stinkbuds Aero set up - out of my budget ;(
Pot size matters 3-5gal is perfect 4 us given space and time-as previously mentioned any smaller and harvest may suffer?
Light matters-Is adding/ supplementing with maybe CFLs an option?
I have no idea if this will help, if it does great if not sorry 2 have wasted ur time

yup 400w try 12 inch flo0wer and no more than 4-6 plants. Light penetration on a 400w is low so smaller plants even canopy works best.

3-5 gallon pots are fine. Like japanfreak said Veg for a shorter time. Plants got too tall and the 400w could not penetrate down far enough to increase yield. Do some lst on them should increase yield and keep them nice and bushy.