Yellow yeaves 24hrs after trimming

[Bluehorseshoe]

New grower here. We did some trimming yesterday, quite a bit actually. There may have been a few yellow leaves but they were all trimmed off. Today 24hrs later a bunch of the plants have a ton of yellow leaves and some of them are even already drying on the tips.

It is an ebb and flow system and we have fed at 7pm last night and again at 9am today.

Does anyone know what might be causing this?

 

[growsince79]

Looks like shes starving. What, how much, and how often are you feeding

 

[Bluehorseshoe]

Looks like shes starving. What, how much, and how often are you feeding

Using GH trio, feeding 2x a day currently. 5min flood. Gets about 1inch-2inch of watering from the bottom of the block in that 5 mins

 

[growsince79]

What ph and ppm?

 

[Bluehorseshoe]

What ph and ppm?

Ph is 6.1 and ppm is 800 in the resivoir currently. About 70 days into veg.

 

[growsince79]

I used to grow hydro but never in rockwool. But it looks hungry. Also that's a big plant for such a little cube. How often do you flush and change the reservior?

 

[growsince79]

New grower here. We did some trimming yesterday, quite a bit actually. There may have been a few yellow leaves but they were all trimmed off. Today 24hrs later a bunch of the plants have a ton of yellow leaves and some of them are even already drying on the tips.

It is an ebb and flow system and we have fed at 7pm last night and again at 9am today.

Does anyone know what might be causing this?

Are you running 18-6? What time do the lights go out?

 

[Vagician]

Lower leaf yellowing is usually indicative of nitrogen deficiency. The upper portion yellowing could be magnesium; if I could see the growth tips better I would be able to decide if it is iron instead. If those growth tips are yellowing then iron deficiency is also a suspect. The plant in general looks hungry.

With a plant that big you should be watering the entire cube over the top almost twice a day. Just getting the bottom two inches is going to be very limiting on your yield. You've got all that cube and if only the bottom two inches are getting watered then the rest of the cube isn't growing roots as well as it could. Your pH and ppm are where they need to be for a plant of that size but the plant isn't able to take up enough of the nutrients to be able to support the entire plant.

 

[Bluehorseshoe]

Are you running 18-6? What time do the lights go out?

Yes, 18-6. Lights go out at 1am. Using HLG 550 rspec

 

[Bluehorseshoe]

I used to grow hydro but never in rockwool. But it looks hungry. Also that's a big plant for such a little cube. How often do you flush and change the reservior?

Zero flushing but we change resivoirs every 7 days and do a deep cleaning on everything. It might be worth noting that we are using hydroguard in our formula because we had some issues with algae but that has mostly solved the issue.

 

[growsince79]

I'm going to have to agree with vagician. Deeper longer waterings might do the trick. You may even need to go 3 times a day.

 

[Bluehorseshoe]

Lower leaf yellowing is usually indicative of nitrogen deficiency. The upper portion yellowing could be magnesium; if I could see the growth tips better I would be able to decide if it is iron instead. If those growth tips are yellowing then iron deficiency is also a suspect. The plant in general looks hungry.

With a plant that big you should be watering the entire cube over the top almost twice a day. Just getting the bottom two inches is going to be very limiting on your yield. You've got all that cube and if only the bottom two inches are getting watered then the rest of the cube isn't growing roots as well as it could. Your pH and ppm are where they need to be for a plant of that size but the plant isn't able to take up enough of the nutrients to be able to support the entire plant.

What you're saying makes a ton of sense. And is actually kind of relieving that it might not be a bigger problem. I'm adding a couple of other pics...

 

[Bluehorseshoe]

First feed is at 9am, lights come on at 6am. Could that be a problem that the lights haven't been fed for 11-14hrs