First time hydro grow, what went wrong? Please help!

I made an attempt at growing a plant for the first time ever and I got a rediculously low yeild and I'm trying to figure out what went wrong. I'm a total newbie so please forgive my ignorance. Here's what I did and some pics to go along, any help would be appreciated for my next try:

I used an existing greenhouse hydroponic setup that grows vegetables (I'm no hydro expert though). I ordered 'Blue Mystic' feminized, auto-flowering seeds from Nirvana. Nirvana claimed a 5-7 week flowering time (which I assumed is when the buds will be ready for harvest, is this a wrong assumption?). I planted the second week of June and harvested the second week in August (9 weeks after sprouting). I had a little problem on the 5th or 6th week though, the plant got what appeared to be spider mites. I sprayed the plant with an organic pesticide used for vegetables. The day the plant was sprayed must have been the hottest day of the summer and a lot of the hairs on the buds as well as some leaves got burned. I realized afterwards that it should have been sprayed at night rather than in the morning to avoid the burning but it was too late. The spider mites went away. With in a week or so the hairs grew back and started turning from white to red again (as I hoped they would). By the 9th week, the buds looked small but good and the plant smelled great. I decided to pick it considering it was the 9th week. I hung it to dry for over a week and the overall results were a dissappointment. The plant shrunk significantly and once cleaned yeilded only 4 grams of bud (as opposed to 200-300 grams that Nirvana estimates). What did I do wrong? Was it harvested too early? I have two more plants that are just getting started and I would like better results this time. Any suggestions or help would be greatly appreciated. Take a look at the pics below, the first two are of the plant the day I harvested. The third pic is of the plant completely dry. Thanks!

how much light did you have on it..........200 to 300 grams........those numbers are allways inflated lol autos typically yield about and ounce under good conditions altho I'm sure some one that knows wut there doing with hydroponics can make that yield bigger

It was in a greenhouse so it was getting natural sunlight. Thanks

autos like to be started off in the pots that there going to finish in and the bigger the pot
the biger the plant will eventaully grow.
bigger the pot = more roots = fast and healthy growth along with the rite amount of light and right temps
also some autos turn out better than others its all down to gentics
lowlife auto ak47 is a good producer and is ok for beginners i'm no pro but i hope this helps

usually its the light that causes that but if your in sunlight, then i would have to say part of it was the plant being shocked. you have to give the plant more time to heal and cant pick it at the "set" date. also those numbers represent meters squared. did the plant grow to be three feet tall and three feet wide? and again your using a ruderalis, these types of plants were not designed to be heavy yielders. they come from the mountains where its cold and the light is scarce. that plant is sold for indoor with little grow space on 24hr light. most people i know that have tried those, never use it again. if your using a scrog method, this would work, but also they are not as potent anyway. another thing with there growth cycle is; you cant have a mother plant, you have a very short cloning window, and they will die after "x" amount of time. personally, i hate autoflowering. if you mess up, you cant nurse it back and give it a little more time, it is what it is. this is not love for a plant, its wanting fast smoke. theres tons of organic pest controls to choose from, just be careful there not too strong. i switched to indoor growing with hydro and have not had any bug problems in the past year. oh and all these autoflowering strains that come out may be designed to be more potent than an original ruderalis, but there incredibly unstable hybrids that will have extreme differences in phenotypes leaving you with unconsistant results. good luck and just take it as a learning curve, hell it took me two crops before i learned how to even use hydroponics correctly. the only thing i did smart with those crops was to use mid grade seeds cause they turned out horrible. first crop had all males or hermies from all the stress i put them through. second i took too many peoples advise and ended up killing them from nute lockup (it was so bad flushing it in plain water for a week showed no improvement). so just take your time and read as much about it as you can, peace!

Thanks everyone. I guess autoflowering plants aren't the way to go. I was just unsure what to start with. I want to grow a plant that doesn't get too tall so that it doesn't stand out in the greenhouse. I also wanted a plant that will bud in a reasonable amount of time under an outdoor light cycle. Since I'm growing in a greenhouse that relies on natural light, I have no control over the light cycles and I can't really mess with the nutrients in the system or ph levels as the main crop is vegetables. I also didn't want anything too complicated considering I'm a beginner. Any suggestions on a feminized strain that will produce a good yeild under any light cycles (and doesn't get too tall)?

mmmm. thats hard. most outdoor strains are sativas which grow tall. indicas grow short and flower faster and there are alot that are equally suited for outdoor. since your starting out id stick with nirvana as the seed source. its pretty much up to you. you can prune and train plants to stay short and bush out, but if you dont want to get that far yet my personal choice would be northern lights. easy to grow, stable, nice yield, and great all around smoke. you could possibly control the light cycle by adding a light in the greenhouse at night until you want it to flower.

the church would be a good option for you its mold resistant and its an easy going plant it just powers on in most conditions

What type of vegetables are in there. If your plants aren't getting the right nutes then they will never grow right. Also ph is super important if it's too high the plants wont be able to uptake certain vital nutrients and die. You might be able to grow in the same system as tomato's and they would hide some of the size. I would just grow in pots in the green house or build a copy of the system in the green house and move it indoors. good luch