Slow growth yellow leaf edges what to do?

So I got weighing scales and soil moisture sensors to diagnose the soil humidity, turns out it was nearly 100% dry so I slowly sprayed 2L of water yesterday and now she is looking much healthier. Leaf damage still looks the same but the plant is stronger and leaves straighter looking good. I am going to get some epsom salts and give her a light spray to reduce stress

@Thinlizy thanks for the answer! The reason I try to water 'not too much' is because my 2nd grow I had problems that looked like nutrient deficiency/excess and send images to biotabs and they said it was overwatering, so I stopped watering those plants in 25L that were 'overwatered' and 8 days later they had dried out completely :') You could be very right that I need to water more, even though it looks like overwatering symptoms I feel like I don't give much water. I weigh the pots everyday, the initial soil mix was 7kg, the pot's weight fluctuates between 6.5 and 8kg, usually I water 1L when it is around or just below 7kg. 7kg was the weight of the pot, I assume the plant currently weight a few hundred grams so seems logic that I am not giving enough water, but since I am not sure it is usually more safe to give less than too much water, so I will let to pot go to 6.5kg then water to 7.5kg like 2 times in the next week to see how that goes, if it stays the same/gets worse then I will water more to keep it 7.5-9kg and see how that goes... VPD seems good although it is slightly dry for the temp so my current VPD is actually optimal for flower but should be ok for veg right? 24c 50-60% day time

Another thing is the vpd of your tent where is you temp vs humidity. Do a Google search for a vpd chart and see where your number put you . Are you in the optimal spot .

I honestly had the same issue plant looked all droopy like that and same for the leaves and my issue was over watering.

Hey SlowpokeFuegobud! Thanks for your answer(s). So yes I water approx 1-1.5L 2x a week, since the plants are small and the pots are big (I started the seeds in these 25L pots) I don't water too much otherwise I am scared of filling the bottom of the pot with water that loses oxygen and then the roots can't fill that part of the pot. I am using fabric bags, and I put a mesh under the pots so they are 1-2cm above the ground and air comes from the bottom aswell. Now that the plants are big enough to give some more water I will try what you say and give more water. Jeremy from buildasoil recommends 5-10% of the pot volume per watering (specifically for living soil!) so I will try to water 10% which is 2.5L for my 25L pots. I also just checked mars hydro recommends the light at 50-75% and 40cm for this stage and my light was 35% and 40-50 cm most of the time so I might increase the light a bit (also 24c during day so increased light can help get 26-27c hopefully)

Hi! :) Maybe it's just potting stress. If you feel like increasing the metabolism, maybe increase the light or the temps + lower humidity? Get well soon, plant! I just saw your watering strategy is giving only 1L of water? Just to compare: In a 25L pot I'd water at least 6 litres each time, until there are no dry spots, and then wait until 70% of the water is gone (so the pot would be 4kg lighter). I have no idea whether your strategy is wrong, but maybe that causes overwatering problems..

The light is a 300w mars hydro sp3000, dimmed to use approx 130watt for 2/3 of a sq meter. I just measured the light is 42cm from the tip of this plant, just moved the light to 50cm from the tip. The pot has 25L of soil which initially (when bought from the store) weighed 7.4 kg and was not completely dryed out. I weight to pot to water, the weight fluctuates between 6.5 and 8kg, usually around 7-7.5. It could very well be overwatering but I can barely give less water otherwise the soil turns to complete sand. 14 days ago the plant was droopy due to underwatering once, then became perky again after watering. It would very well be due to too many nutrients early on making it difficult for the roots to spread evenly through the soil causing imbalances in the soil. Could also very well be overwatering or just wrong watering practices, I aim for watering 2x a week and every day to a light top spray just to make it slighty wet so the new companion plants don't die. Maybe I should move my light even higher, I thought they could use more light but didn't change the light settings in 20 days since the internode distance is short but the stems are not turning red (they usually turn red with too much of this led light). I will move the light again to 60cm above the top of this plant for a few days and see how she reacts...

I would t say its overwatered, what was your light power and distance to plant?

@GrowingGrannie Thanks for your answer! It could be the ph but I am using 'living soil' as medium for which it is recommended to not adjust the ph. I have used the same water the previous 2 grows and some plants made it through being watered 4 months with non-phed water and still looking nice and green with no deficiencies. Biotabs recommends to not adjust the ph of the tap water and the other plants in the tent have more or less no deficiencies. I used to grow in hydro so I still have all the stuff to adjust water ph (in this case I would use the organic plagron lemon ph down if necessary) but adjusting ph is really a last resort I think something else is wrong - it could very well be a nutrient imbalance causing ph imbalance in the soil but I am not sure if adjusting the water ph is the right way to solve this in a 'living soil' approach.

Are you checking the ph? I had that problem (yellowing, etc) and found the nutes were drastically altering the ph of the soil... that's the first place I'd suggest you check.

Also the leaves look more droopy in the picture: I bent the fan leaves to go under the branches to give more light to the branches with new internodes so the top fan leaves seem to be hanging down more than they do.

The plant in the pictures is day34 from popping above the soil. Also I use a mars hydro sp3000 led light which is known to require more cal/mag from the plants, I did not yet supplement the soil with dolomite lime. Soil mix used: plagron promix + 25% perlite mycotrex (mycorrhizae) startrex (grape compost) bactrex (beneficial soil bacterial) orgatrex (molases) biotabs (slow release organic nutrients + bacteria I think?) I put in 1.5 biotabs after germination, I realize that I should only have added the tabs after 15+ days. Do you guys have any idea what the problem is? The other plants in the tent grow slowly but seem healthy... Should I reduce watering or mix in dolomite lime or something else or just wait? Other stats: 24c/20c day/night, water 2x a week 1L, light spray top soil every day (alfalfa and white clover just germinated)