Potassium def?

From the 1st picture I'm pretty sure I have a potassium def. The sides of the lowers leaf become brown, discoloration, leaves becomes weak and dries.

But the nexts pictures show what is happening to top leafs. It's seems to be more obvious on the biggest buds. Leafs start to have discoloring spots and small brown spot almost like calcium def but it's not showing on the lower leafs.

I'm in Coco. I've started with 6:9 Heads formula and at the beginning of flowering I had sign of nitrogen toxicity so I lowered the micro. right now I'm running 5ml gh Flora micro 11ml gh Flora bloom (also started to raise bloom a week ago) +1ml calmag.

25°C / 50% RH
Watering every 4 hour. Total 1.5Gallon each day per plant.
1000HPS


Thank for any input.

you probably feeding hot and your ph probably is above 6.2...my guess

what's your EC and ph?

EC is 620ppm (0.5f) and I try to keep pH around 5.8-6 usually when reservoir raise to 6 I pH it down to 5.8.

But right now it's at 5.75 I did put a little but to much pH down when I top off the reservoir

at the data you provided that shouldn't be happening to your plants. is that the data inside the reservoir or are they the data of your mix prior you mix it with your reservoir?

when was the last time you changed the reservoir?

honestly the picture says nute burn and nute lockout, imo.

I've run my plants over 1500 ppm or over 3 EC with no adverse effect so in essence 620 ppm or 1.2 EC is nothing to your plants and shouldn't be showing burning...deficiency maybe but your pics are showing toxicity

I'm drain to waste. So what I mix and put in the reservoir is exactly the same beside pH.

I try to ph the batch I mix 5.75 then add it to the reservoir and it raise close to 5.8-5-9 thru the night and I check the reservoir once every 2-3 day if it raise to 6 I add pH down until I get 5.8. so pH always stay in the range of 5.8-6 sometime 6.1

It's been a while since I didn't dump/rinced the reservoir. Do you think it's needed? It's a 15gal reservoir and I add 5gal to it daily so it's pretty much always new stuff...

I may try to flush them with low ppm solution and clean the reservoir tomorrow.

Maybe its the pot size too. They have vegged in the same 2.5G they are in right now and they vegged for about 2month (timming issue)

Measured runoff ppm today. Its 320ppm thats odd, the tips are burned like they are getting too much....

Glenkush said:

Maybe its the pot size too

Click to expand...

pot size? what kind of system are you running? is it the fabric pot filled with hydroton? If so, it might be holding some salt builtup in there and just not showing in your water.

Glenkush said:

Measured runoff ppm today. Its 320ppm thats odd, the tips are burned like they are getting too much....

Click to expand...

that's what I been saying, your nute seems to be in the low side but your plants seems to be showing toxicity or burning.

2.5 gallon plastic pots
75/25 Coco/perlite