You want tight nugs, you need the genes, OG Kush should give you delicious tight nugs if grown correctly. So what does "correctly" mean? All plants grow by using a process called photosynthesis. For photosynthesis to work, 3 elements are needed, CO2, Light and water. CO2, If you do not have a sealed room with AC and CO2 ammendments then you need to exchange the CO2 depleted air between once and 4x per min. Calculate the volume of your room, decide how many times per min, multiply the two. Add 15% for any bends in your ducting and 25% if you have a carbon filter. Just using an oscillating fan will not replenish the CO2. Light, MJ needs a minimum of 3,000 lumens per sq ft of canopy in the blue (6,500k) spectrum while in veg and 5,ooo lumens per sq ft of canopy in the red/orange (2,500k) spectrum while in flower. You have a 600W light which will produce around 90,000 lumens. You have 10sq ft so you have plenty of light despite what someone said about needing a 1,000W. During veg, you can use a MH bulb in that light and get good results. Generally, airy buds are the result of either too little light, poor humidity or high temps. I will assume your water is good since it will take a long time to detail what constitutes "good" water. Thats the basics for growing however the environment needs to be good also, which means temps, humidity. Temp, as someone mentioned needs to be between 75 & 80 deg, with 78 being perfect. Humidity, should be in the 40% to 60% rh range. Get these wrong by 10% and it can cost something like 25% yield. (I tested this over a long period with several strains) So, you have light, CO2, water, temps, humidity and genetics. This is like saying to a human you have light, shelter, clothing, comfortable temps and humidity. But why isnt the human growing??? The poor thing is starving!!!! You MUST feed your plants. Even if this is time release fertiliser (for the stupid, idle people out there) your plants need food. The brand doesnt matter but companies like Advanced Nutrients, Canna, General Hydroponicws, Dutch Pro, Ionic etc all make products specifically formulated for our preferred plant. I would suggest using their expertise. Green mojo dude. W