Phosphorus is what is primarily utilized by the plants to form bud structure. If your low on that then your girls arent going to produce. Plus it's an Autoflower, which i consider dogshit for indoor growing. They are inferior to photo period plants in every way. You want big fat resinous dense buds with a huge yield, try Barney's Farm Critical Kush. It's a 24% THC 8 week flower shorter stature variety.
I say take the Autoflower's and use them where they are intended....OUTDOORS. It actually makes me laugh when i see people growing them inside, and at the same time it makes me mad because the seed sellers lie to you to get you to buy a seed that you cant grow up as a mother, you can't clone it, you can't do fuck all with it except watch it grow and die. Then fork over more cash for more useless autoflower seeds.
Jump on the winning team brother. Get photo period plants and fucking clone them off clones off clones off clones, or grow it into a mother and have endless 1st generation clones, and stop making these piece of shit autoflower seed sellers and breeder idiots rich.