Older leaves drying up in hydro grow

[plastic.catcher]

The plants are growing strong overall and producing pretty well, but throughout the entire cycle the oldest leaves keep turning pale, then drying up and going crispy. It only ever happens to the older leaves and doesn't matter the length of the plant, the younger growth and tops stay lush and green, so the plants don't look sickly as a whole.
I'm running a recirculating system with a good airflow, pH around 5.9–6.1, and temps in check. Nutrient levels are steady, and I've double checked that I'm not overfeeding. At first, I thought it might be light burn, but the problem keeps happening even to shaded lower leaves. What can I do?

 

[UrbanFarmWizard]

I think you're dealing with classic nitrogen deficiency, your plants are actually using their older leaves to support new growth. Even if you're providing a steady stream of nutrients, nitrogen can get used up pretty quickly in recirculating systems. Try boosting N slightly or switching to a mix with better N balance.

 

[Mcart]

The plants are growing strong overall and producing pretty well, but throughout the entire cycle the oldest leaves keep turning pale, then drying up and going crispy. It only ever happens to the older leaves and doesn't matter the length of the plant, the younger growth and tops stay lush and green, so the plants don't look sickly as a whole.
I'm running a recirculating system with a good airflow, pH around 5.9–6.1, and temps in check. Nutrient levels are steady, and I've double checked that I'm not overfeeding. At first, I thought it might be light burn, but the problem keeps happening even to shaded lower leaves. What can I do?

Many plants will naturally pull nitrogen and other nutrients from the oldest leaves to feed new growth, especially if the plant is putting energy into fruiting or flowering. As long as your new growth looks healthy and vibrant, it's usually not a sign of deficiency that needs immediate fixing

 

[HELYAB]

It sounds like you're keeping your environment pretty spot on, so this might just be the plant relocating nutrients. Older fan leaves are often sacrificed when the plant transitions from vegetative growth into flowering or putting energy into buds. As long as your new growth remains lush, it's usually not a major problem. If you'd like to slow it down, you can give a slight boost of nitrogen and magnesium during early flower and make sure your pH pen is calibrated so uptake stays consistent. Removing the dead leaves will also improve airflow around the canopy.