Brown Spot on leaf

specifically the interveinal chlorosis (yellowing between the veins) and the browning/bronzing patches on the mid-fan leaves—are classic signs of a calcium and/or magnesium deficiency. Here is a breakdown of why this is likely occurring given your current grow setup: PH Imbalance: The most common cause for nutrient deficiencies in indoor grows is an incorrect pH level at the root zone, which locks out these specific nutrients. Even if the nutrients are present, the plant cannot uptake them if the pH is outside the optimal range for your substrate. Growing Medium: These systems are highly sensitive to pH fluctuations, which can frequently trigger secondary deficiencies like these. Developmental Stage: As the plant undergoes rapid growth during this phase, its demand for secondary nutrients like calcium and magnesium increases significantly. Suggested Troubleshooting Steps: 1. Check your pH: Before adding more nutrients, measure the pH of your runoff water. If it is too high or too low, this is your primary culprit. 2. Evaluate your current feed: ensure you are not experiencing "nutrient lockout" caused by high salt buildup in the medium. A thorough flush with pH-balanced water can sometimes reset the root zone.

Hi, from the photo it looks like a nitrogen (N) deficiency. The yellowing on the leaves, especially on the lower parts, is typical when N is lacking, as the plant moves it to the new leaves. Check the pH of the watering water (6.0-6.5 in soil or 5.5-6.2 in coco) and give it a watering with a bit more nitrogen (slightly increase the dose of your growth fertilizer), but don’t overdo it. Also add a bit of Calmag if you have it. It should recover quickly. What phase is the plant in and what nutrient dose are you giving it now? 👍

The yellowing at bottom tip-in on leaft and creeping up would be N deficiency, but i think the mid level leaf is something else. Root zone maybe too hot (temperature, not nutes).. Emenating from the vein makes me think root zone related..It's a weird location and progression, so i'd look into rootzone and environmental changes lately. if it doesn't spread, don't worry. outdoor plants show more blemishes / exposed to more things etc. If the chlorosis seen on the lowest leaves progress up the plant, add a bit more N and keep the rest the the same as best you can, unless other symptoms give a clear answer that something else is coinciding..