k deficiancy?

Need to see where on the plant the first leaf is from.

The yellowing leaves in the second pic are definitely from nitrogen deficiency. Keep in mind that deficiency damage doesn't heal. When you fix the problem, it just doesn't spread to other leaves, but the damaged leaves stay damaged.

 

That's probably early Phosphorus deficiency.

 

I don't think it is potassium. K+ deficiency appears more along the leaf edge and is usually accompanied by an upwards curling of the leaf. It is a deficiency, but it looks across the board (everything from nitrogen to magnesium) and is probably just the plant cannibalizing itself for flower production. This is extremely common in organics and really shouldn't be a concern for most growers. If the issue is gradual then I would expect it to be a natural process. If the issue is sudden and getting worse fast then I'd think it was more of an issue with the root zone. Perhaps a pest like root aphids or fungus gnat larva, or maybe a simple element imbalance. If there are no bugs present then a good rinsing (3 gallons in, 2 gallons out kind of thing) should remove any buildup. After the rinse you can top her off with a good balance of bloom nutrients for those organics to chew through so your plant can get what she needs out of the soil via the root system.

 

The defining trait of Potassium deficiency is yellowing (& ultimately necrosis) along the leaf margins, as SCMC stated, but it causes downward curling. Phosphorus def. causes upward curling. Here's a good pic of K def:

 

You may need to start upping the doseage.

 

Not entirely accurate as phosphorus deficiency will cause downward curling as well. The curl of the leaf is often situational.

The reason leaves will curl upwards is to assist in the rate of transpiration. The leaves sweat to keep themselves cool. If the room is too warm, or too humid, the leaves will curl upwards in an attempt to cool themselves better. The process that pulls water up through the root system and to the leaves for evaporation brings in other elements. Namely Calcium. This interferes with the Potassium cycle.

So it's not that leaves curling one way or another will necessarily indicate the issue. If the temperatures are on the higher end then due to the purpose of Potassium in the plant the two symptoms are commonly presented together despite being a priori.

Not that I was citing his lack of curl as evidence against potassium deficiency but it just didn't seem as likely given the other physical appearances of the plant. Though, I have been wrong before...