That depends on your geographical area you are growing in and the strain type. Indica flowers earlier, sativas flower longer. Hybrids somewhere in between. Sativas have skinny long leaves, indica has fat leaves. Hybrid can be either or in the middle. Typical time for harvest is CROPTOBER. I’ve had plants ready in late September. And I’ve had some go to November depending on what strain it is. That’s in Colorado. You want to be harvested before heavy frost sits in. Pay good attention to your buds for mold also in late season.
Sometimes you have to actually pull the bud off the stem a bit on your big colas to check for mold. If you see any don’t freak out and just remove the molded part. Also some critters like cannabis.
For me it’s caterpillars that try to get in there. Really inspect you buds come that time. Make sure you get the males out unless you want seedy buds. Look for two hairs indicating female. Sometimes it won’t show sex right away either. If you see any sacks hanging it’s a male. Also make sure your stems have support when those buds start sagging. Happy growing.