Nute burn or deficiency?

Seed: ILGM sour diesel auto
Soil: Fox Farms Ocean Forest
Pot: 2 gallon fabric
Light: Mars Hydro TS1000
Water: First four weeks was tap water and would use Ph down to get it to around 6.5. Subsequent weeks: bottled spring water
Nutes: None

I’m in week 6 for these plants. For the first few weeks, everything seemed to be going fine with the plant. They were growing at a good rate and the leaves looked healthy.

Around week 4, brown spots started appearing on some leaves. Also at the start of week 4, I realized the Ph of the water, after sitting for a day or two, was climbing back to around 8 after Phing it to around 6-6.5. So, there were likely several times when I gave the plant water that was way too high in Ph. Starting in week 4, I would get the water to an appropriate Ph (6.3-6.5) level and water the plant immediately.

But the brown spots on leaves continued, and some leaves started turning yellow and were dying. Some stems were purple/red.

At the start of week 5, I decided to switch to bottled spring water, thinking the tap water may have been part of the problem (chlorine, chloramine, etc.) The spring water happens to be at a good Ph, around 6.5.

But the issues persist. At first I was thinking it was a deficiency since I have not given them any nutes, but new growth has burnt leaf tips. So I’m a little confused how this could be nute burn, and if it is, why there was no signs of it during the first few weeks.

Throughout the grow, I’ve occasionally checked the runoff after watering, and it’s around a Ph of 6.

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Time to start adding nutes. Maintain a runoff PPM of ~1,000.


+1 on time to start feeding. She’s gonna start getting hungry real fast. The nutes in ffof only lasts about 6 weeks, also giving a dose of cal mag every other watering wouldn’t hurt. Have you checked the ph and ppm of your runoff lately? I’ve found that the ffof creeps down a bit. I was having runoff as low as 5.5. I top dressed with a little dolomite lime and watered in good and it helped stabilize my ph at 6.5.

So is there a deficiency that can result in burnt leaf tips and edges only? I’ve read through God knows how many articles on deficiencies but could not figure it out. The Ph of the runoff has been OK, around 6.

I have a Ph tester but not a TDS tester. Do y’all think one is essential?

Looks to me like an overwatering issue. Are you letting the soil dry out between watering?

I’m pretty confident it’s not overwatering. I only water when the soil is dry.

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As the others said 6 weeks in FF soil time to start feeding

TDS meter is essential, your runoff ppms give you an idea where your nutrient levels are at.

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