Brownish Spots on 2 Older Leafs. Young plant.

88F is too hot. 84F max and anything beyond that the plants will stop transpiring in an attempt the preserve moisture. Humidity is good for veg at 60%. Be careful not to give too much water. And your plant is young and still fragile. Your light should be 18" above your plant and dimmer set to 50% Plant is young and needs to work up to more intense light. I don't think your plant looks too bad. I think the damage is from lack of oxygen in the root zone due to too much water in the soil. There's a lot of growers that over water around here. And on a side note, is it just me, or do i see that people with plant problems always seem to be using Biobizz nutrients? I swear... You need to get your temps down man it's too hot. Back off on your watering a little. Let soil dry out so the pot feels light, but not to the point of wilt. Then give her only what she needs. If she's 2.5 inches tall she doesn't have a very big root mass yet so there's no need to saturate your soil. Just around 100ml piddled around the plants stem about 1.5 inches away. Don't worry, it will wick around the medium and moisten more than just where you watered. You can be the judge of what she needs. Less is often more when growing young seedlings, and weed in general. When you noticed the change in your lower leaves was it showing up after a watering? How often are you watering and with how much water? Are you feeding every watering or alternating? You should alternate. Get some air moving around in there if you don't already have an oscillating fan going. A gentle indirect breeze they love! And it will strengthen the stem and clear out used up co2 depleted air around the leaves and allow for new co2 rich air to blow in. I think you got over water issues. I doubt at this early stage you have a deficiency. And there's no reason to suspect mold or fungus or a viral or pathogenic issue. If you are misting your plant because you think they like that, stop. They don't care about being misted. All you are doing is creating a pocket of stagnant water on the leaf surface which can be a pathway for pathogen invasion. Droplets of water can also act as a magnifying glass and concentrate the light which can burn your leaves. Unless you are foliar feeding, which is of benefit on the underside of the leaves, not on the top of the leaf, then just don't bother, it's worthless.

Nope no fungus, its just to much of all food and light, how about your waterings? she should get only 10 -50cl daily

What I found after some research and that LOOKs like its my problem: SYMPTOMS Lower leaves develop small, ¼- to ½-inch (6 to 13 mm) pale ocher or light brown spots. Tiny, black fungal fruiting bodies appear inside spots. Spots grow larger and may have yellow halos. Tissue inside spots darkens and dries up. Spots may be rounded or angular (confined by leaf veins). DIAGNOSIS leaf spot, canker, and fungus: brown leaf spot (Neodidymelliopsis cannabis, Ascochyta arcuata), yellow leaf spot (Septoria cannabis, S. neocannabina), Cladosporium stem canker (Cladosporium herbarum), Chaetomium fungus (Chaetomium succineum) SOLUTIONS • Sanitize • Weed • Mulch • Use baking soda spray • Use copper • Plant polycultures • Create healthy soil • Decrease nitrogen • Keep foliage dry What do you think are my issues? Let me know if you need any additional information.

your seedling sits in a biiig bucket full of nutrients /( soil) she dont need any NPK at all so your girls just overfed and ima looking into the diary to look for the lights,