This is a leaf symptom I've seen before but can't figure out what is causing it...

These are seedlings that are now about a foot tall.

1 gallon pot with roots organic soil.
Watered only when pot has dried down. Basically been watering every 4 days or so.
Watered with plain chlorine filtered water, no nutes.

These are outside under shade cloth, the temps are high at mid to upper 90s.

What is causing this?

I would transplant to a bigger pot.
The plant has depleted all the nutrient in the pot most likely and you may be underwatering.

Thats no seedling.

Transplant into new soil will probably fix your issues.

1 gallon pot is not idea anymore for that vegging plant.

Wizzlebiz said:

Thats no seedling.

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I just meant that it started from seed, if that even matter.

There is no way I am under watering, but I might be under nuting as I've not added any nutrients.

I'll try transplanting and giving them some added nutrients.

tilopa said:

I just meant that it started from seed, if that even matter.

There is no way I am under watering, but I might be under nuting as I've not added any nutrients.

I'll try transplanting and giving them some added nutrients.

Click to expand...

The roots become bound in a pot that size. The nutrients become used up.

When you transplant you are putting the plant into a new nutrient rich environment. You will not need to add additional nutrients for a couple of weeks after transplanting.

That's why I suggested doing the transplant. It will solve alot of issues with very little work.