Yellow leaves at the bottom of the plant

As your plant is not flowering yet, I agree with Inhaledmonkfish, the damage is most likely from the leaves being in contact with the moist substrate during the night when the plant lowers its leaves. Unless the problem progresses or gets worse, there is nothing really to worry about at this stage. You could cut the leaves off or trim off the damaged parts if you are disturbed by their appearance, otherwise you could just leave them and they will most likely go completely yellow and fall off naturally. In the meantime they will still be producing some energy, that your plant can use for growth and they will also provide some sugars, amino acids, carbs etc that are already in the leaf, that your plant will draw out and reuse for growth elsewhere. This is why the leaf is going yellow, your plant "recognises" that the leaf is damaged as indicated by the brown parts and she is slowly moving the vital growth elements (carbs, sugars, amino acids etc) out of the leaf to use in the healthy growing parts of the plant, causing the yellowing of the upper parts of the leaf. This is why it is also wise not to remove any leaves unless they are yellow, for not only do the healthy green leaves make all the energy your plant needs for growing, they are also "storage" sites of vital growth elements that your plant cleverly builds up for use during flowering. As flowering is such a energy intensive activity, reusing the "stored" elements from her leaves is far more efficient than trying to grow flowers and make new growth elements from new, at the same time. This is a basic principle the defoliation brigade fail to understand; removing healthy green leaves not only reduces your plants capacity to produce energy, it also robs her of the vital growth elements that she has so cleverly stored in those healthy green leaves for use during flowering. Removal of healthy green leaves = less energy produced = less growing ability = smaller growth = less (available) ready made vital growth elements. They will also say that removing leaves exposes "potential bud sites" to light so that they can grow, but without those very same leaves to produce the energy to grow, removing the leaves just slows the "potential bud sites" potential growth. So it really is a lose/lose situation, You can't get fast growth without the big healthy green leaves producing energy. The small leaves associated with flower growth can in no way produce anywhere near the same energy as just one big green healthy fan leaf. Another thing they don't realise is that light, some of which humans can not see, will penetrate upper leaves and strike lower leaves and stimulate photosynthesis anyhow. They will also say that their plants bounce back and "explode" into new growth after defoliation. However, a plants first reaction to losing leaves is to produce new leaves, to bring energy production levels back up to where they were before the leaves "went missing". So, basically they are cutting off healthy green leaves which encourages the plant to grow new healthy green leaves, which is an absolutely pointless exercise, wasting the plants energy, energy that could actually go into flower growth and not leaf growth! The other thing they fail to observe is that since they think their plants "bounce back", usually after a period of stasis/no growth while the plant tries to work out what happened to cause her metabolism to dive, is how much growth would have occurred had they not removed any leaves and left their plants to continue growing with 100% of the plants metabolism intact and without any traumatic metabolic shock, which can in some cases cause weird things to happen, such as hermaphroditism or stagnated flower development. So remember; less/fewer healthy green leaves = less energy produced = less readily available stored vital growth elements = less/smaller growth. This is basic plant biology. Sorry for the "off topic" ramble, I do feel better now, having had one of my endless rants concerning leaf removal. I feel like the protector of "healthy green leaves" and just want people to understand that in order for a plant to grow her maximum flowers, she needs maximum energy, which can only be provided if she has her maximum amount of healthy green leaves. I think I will go and have a lie down now and recover for a bit. Hope this helps, in any way, even if it is a bit "off topic". Sorry for the sermon. ,..... Organoman.