Yellowing leaves under leds

[copperfacedave]

Having problems with leaves yellowing in Coco. The pH may have been a little low it's at 6 now the EC is usually 1.6 including calmag

 

[Dr.NO]

Looks like it could be a potassium deficiency.

Your coco looks dry on top. Coco should be kept constantly wet. Otherwise the lack of water will leave the fertilizer salts more concentrated and greatly lower the pH which could lock out various nutrients.

 

[TanzanianMagic]

It's a mobile nutrient deficiency/lockout (NPK, Mg) because the damage starts in the middle leaves and moves up, and the damage to the edge of the leaf looks like Potassium (K).

There are issues with K in coco, especially indoors.

The plants look a little busy, and pruning back the lower 1/3 of growth and a few inward growing branches will help a lot to concentrate future growth and waste fewer of the plant's resources.

It's hard to tell how big the pots are, however your rule of thumb should be 1 gallon (3.78 litres) for 1 foot (30.48cm) of expected growth of an unpruned plant. Bigger pots allow for bigger root systems, which automatically enables the uptake of more nutrients. Also, flowering is basically an expansion of the root system - which is why weed flowers so heavily in hydroponic systems, where roots just grow into water. You can only replicate that in organics, by at the time of flowering:

- repot into a larger pot
- add at least 2 inches of soil on top of the soil
- start flowering before the roots have colonized the entire medium

 

[copperfacedave]

Thanks for your help.

There in 10 gallon hempys I veg them till there 5ft tall. Think I need to check the run off see what pH and EC it's coming out at.

 

[Efbespn]

Thanks for your help.

There in 10 gallon hempys I veg them till there 5ft tall. Think I need to check the run off see what pH and EC it's coming out at.

Going through the same thing. Did you recover? Please update on current status. Thank you

 

[paradoxlost]

It's a mobile nutrient deficiency/lockout (NPK, Mg) because the damage starts in the middle leaves and moves up, and the damage to the edge of the leaf looks like Potassium (K).

There are issues with K in coco, especially indoors.

The plants look a little busy, and pruning back the lower 1/3 of growth and a few inward growing branches will help a lot to concentrate future growth and waste fewer of the plant's resources.

It's hard to tell how big the pots are, however your rule of thumb should be 1 gallon (3.78 litres) for 1 foot (30.48cm) of expected growth of an unpruned plant. Bigger pots allow for bigger root systems, which automatically enables the uptake of more nutrients. Also, flowering is basically an expansion of the root system - which is why weed flowers so heavily in hydroponic systems, where roots just grow into water. You can only replicate that in organics, by at the time of flowering:

- repot into a larger pot
- add at least 2 inches of soil on top of the soil
- start flowering before the roots have colonized the entire medium

If it was a mobile nutrient problem it would start in the lower leaves first, as the newest leaves would take from the oldest/least productive leaves, aka the lowest/most shaded leaves. Yellowing starting from the middle, for me at least, indicates a Molybdenum lockout/deficiency. Foliar spray in a chelated Mo spray or add some Mo to the roots, or do both. You can't overdue Mo.