need some more knowledge, first grow was ok.

So i grew four female diesel seeds i got out of some really potent bud, two purple sativas and two sour indicas. I switched them to flower after they got three and a half, four feet tall they looked amazing, smelled great and was covered in crystals. But the purple came out really fluffy and both buds weren't to strong and smelled like home grown and not like how it was smelling and not to much yield off the plants sadly. I grew them in a 7 by4x4 tent 400watt HPS light filter, fans, air duct and humidifier. They were in three gallon pots, used fox farm ocean floor soil, along with using there nutrient kits. I added sugar to the water, and had co2 going for a few hours a day. Would like to know more tricks or other ways i could do for my next grow to have better quality and yeild.

You need more light. What size exhaust fan do you have?

I agree you are under lit.

Thanks guys. And 1200 i think.

1200 cfm fan? you need more light, i am running a 1000 watt hps in my 4x6 room. from what i gather, co2 isnt going to help unless you taylor your complkete grow setup with co2 in mind.

Yeah I agree, you need either a 600whps or a 1kwhps to get really good tight buds. You also need to have very good control over the air and temperatures. You need to maintain mid 70s in the tent with constantly exchanging old hot air with cool fresh air.

You said you got the seeds from a bag of smoke, the seeds that typically come from smoking buds are junk genetics because of certain malfunctions in the creation of it known as "hermy". If you noticed any little yellow banana looking things in your buds, then they detract from the potency and flavor of your bud.

Bud coming out smelling like homegrown hay is due to improper drying and curing(or no curing). When you harvest your buds, they need to go in a place where they can get a very slow but steady current of fresh air to move around them. It needs to be dry, cool air of 60% or less humidity. Depending on how many you got, they need to dry for about 3-7 days. Then they need to be placed in some kind of air tight containers like mason jars or the cheap Tupperware containers, so that the curing process can begin.

The cure requires you to store the containers in dark, cool place. Then take them out once a day, open the containers and air them out for a moment, then close up and put back in dark. Do this for 1-4 weeks. For best results, do cure for 4 weeks and I guarantee if the genetics are any count, you will have good smelling and at least smooth tasting smoke.

The biggest factor affecting yield is your lighting. For those nice tight buds, you are going to need quite a bit more light. A 600W is barely adequate for 16 sq ft and more would be better--either a single 1000W or 2 600W.

Genetics are also very important. Once in a great while you can get something good from bagseed, but generally the results are less than stellar. I encourage you to check out the seeds that are available now and pick something that sounds like something you would love. There is an advantage to knowing what you are growing--you will know the basic plant structure, you will know the type of high, you will know the flowering period, and lots more. Run your choice by the people here before you buy though to make sure the seed bank is reputable.

Do not add sugar to your grow--this does nothing good and can do bad things. Also CO2 unless it is monitored and regulated is a waste of money, time, energy, space. There is a lot more to CO2 enhancement than simply adding CO2 to your grow. Concentrating on the basics will give you the best crops. Leave the fancier stuff for later when you have some experience.

Good ventilation is almost as important as your lighting. You need good air exchange--out with the old and in with the new. This is generally accomplished with a centrifuge type fan that exhausts air out and passively brings air in. Ventilation is for more than cooling your space. Your plants need a continual supply of fresh air all the time the lights are on for proper photosynthesis.

However, you obviously did a lot of things right as you ended up with good bud, just not enough of it. This is a long process and a lot of new growers have to try several times. So, I would say that good genetics, more light, and making sure your ventilation is good will result in a lot better crop for you the next time around. Proper drying and curing will give you that good tasting bud.

I believe that part of the problem is light as stated above, but more importantly it sounds like you were phosphorus and potassium deficient also.