Hey
@Pisstank85,
First, since there are all different strains you should expect each to have its own characteristics. They are not going to grow the same. They also will probably handle the Nutrients a bit differently. As far as the Fugue, the brown spots just look like you got a bit of Nute burn. when you feed tey to keep it off the leaves and if you get the leaves wet you can dab them with a bit of paper towel to get the mix off of them. The Nute spots are common and should not an ongoing problem. It does appear that the leaves are a bit turned down on the Fugue, that is usually a sign of a bit too much watering. Since each of these plants is growing at a different rate you are going to have to watch your watering/feeding, with each one. Don't dry it out, but you might try to back off a bit on the watering on this one. The rest all look good at this point.
You PH is a bit low in my opinion. When you get down to 6 you start to get out of the range where the plants can utilize the nutrients both in the soil as well as what you are giving them. 6.3 - 6.4 is pretty much the standard for soil and Autos.
To answer your main question about feeding.
@ExperimentGREEN is correct, the soil (If Quality Soil) and the seed itself has enough to carry the plants for a couple of weeks. However, having said that I personally start light feeding right after I finish the misting period, usually by the 5th or 6th day they are above ground. But I go light. and I watch them closely.
Lastly, you can not beat good genetics. Not all Autoflowers are created the same, even the same variety from different breeders can be quite different. Always try to get the best genetics you can afford, the extra few dollars can save a fortune of heartache.
Good luck with the grow. Just really look at them, each as their own unique plant.
2 strains
2 strains
