[black_thumb]

I just started using jacks 5-12-26 450 ppm with calnit 300 ppm @ .5 per gallon im having the same problem but mine looks like p def drak crispy brown that starts at the tips about 4 weeks into flowering in coco.

My tap water comes out @ 25 ppm .5 & 6.0-6.2 ph and i have to add alot of pro-tekt to get the ph back up to 5.8-6.0.

So could the pro-tekt along with the already high k level of the jacks be locking out the p?

can you get silica without all the k?

[Jbonez]

Def P def....

4 weeks is about the time I hit em hard with P... Looks like you need to boost your p, Id say if your ph is upper 5's your issues is lack of nutes...

Too high K will block uptake of both P and Mg along with B. imo Jack's has too much K to begin with and then you add more with KSil you are asking for a problem. The fact that Mg has to be so high in the Jacks formula is because the K is so high.

I have better luck running K= N.

If you are using some kind of media...coco, peat/humus then the easy way to add Si is just chuck in some amorphous diatamaceous earth. My favorite is Red Lake Earth which is 67% DE and 33% calcium bentonite.

But Si does not seem to be so important to me to risk raising K levels. Better to run without it entirely than to risk ruining your cation balance.

[BasementBreeder]

Originally Posted by YosemiteSam

Too high K will block uptake of both P and Mg along with B. imo Jack's has too much K to begin with and then you add more with KSil you are asking for a problem. The fact that Mg has to be so high in the Jacks formula is because the K is so high.

Really? I've always read that excess K blocks the other cations, not the anions.

I have better luck running K= N.

Agree 100%. Plants can tolerate very high levels of K, but it definitely isn't needed. Much better to have the cations in balance.

If you are using some kind of media...coco, peat/humus then the easy way to add Si is just chuck in some amorphous diatamaceous earth. My favorite is Red Lake Earth which is 67% DE and 33% calcium bentonite.

But Si does not seem to be so important to me to risk raising K levels. Better to run without it entirely than to risk ruining your cation balance.

Also agree. I think many people do more harm to their nutrient profile from adding extra K then they get from the Si that goes along with it.

[black_thumb]

I use the potassium silicate too raise the PH. This is what my tap water reads before adding anything........

what medium are you growing in black thumb?

[Jbonez]

YS, Ive just switched 5/5/7/5/.5 with agsil (70ppm), what are your thoughts on this, Im told youve a profound insight into nutrient profiles, Im in coco...

[black_thumb]

im growing in 100% botanicare coco 5kg bails.

Here comes one of those imo things that will go against pretty much everything you read on this site. The pH of your fert water has virtually nothing to do with the eventual pH of your coco. The alkalinity of your water will have a big effect and the exact cation/anion balance of your ferts will have some effect although not a huge one since coco does not have a big cec.

I would not use KSil with Jacks period.

Load the coco with some Red Lake Earth for silica if you think it is important. Switch to raw salts and account for the K in your formula.

Either way I guarantee you the excess K does more harm than any gain you get from the silica.

imo...take that for what it is worth to you.

[black_thumb]

I just ordered 20 lbs of MKP, 20 lbs magnesium sulfate, 4 lbs peters S.T.E.M and already have the calcium nitrate. I guess ill put the jacks -5-12-26 on the lawn this spring not much else use for it now.

i dont really care for the silica i was just using it to up the ph. after i add the ferts my ph is down in the 2.8 ph what is that like battery acid lol.