Its Always Something...

[dejayou30]

I think this is a phosphorus deficiency, but I am not totally sure. The edges are crispy and the new small leaves around the buds have yellow, crispy, turned down tips. The guide I read said a little P deficiency in flower is normal, but if P is what it is, I think I have more than a little. What should I do?

PPM is 1150, pH is 5.6, double checked with liquid pH kit. They are starting Week 4 tomorrow.

The last pic is what I would say is the worst looking one.

dejayou30 Reviewed by dejayou30 on 01-04-2008. Its Always Something... I think this is a phosphorus deficiency, but I am not totally sure. The edges are crispy and the new small leaves around the buds have yellow, crispy, turned down tips. The guide I read said a little P deficiency in flower is normal, but if P is what it is, I think I have more than a little. What should I do? PPM is 1150, pH is 5.6, double checked with liquid pH kit. They are starting Week 4 tomorrow. The last pic is what I would say is the worst looking one. Rating: 5

[Weedhound]

Deja....what growing medium are you using....looks like it might be time for a good flush.

[dejayou30]

I'm using hydroton and rockwool. Ugh, I really don't want to flush! I just changed the res!

[Weedhound]

Hmmm....I'm not familiar with RW really but hydroton does get clogged up.....at least mine did and caused the same kinds of issues........not sure how you would "flush" rockwool......

[Weedhound]

Hydroponics - Rockwool as growing substrate

Don't know if you've seen this rockwool info.....might be worth a look through. I just am not sure about flushing the stuff.....it holds so damn much water.

[dejayou30]

Could I just take the baskets out and hose them out? And would it matter if the hydroton is clogged if the roots have well outgrown the basket and are hanging down from it?

[dejayou30]

Well, by the end of the last grow, the stem of the plant was about as thick as the small rockwool cube, so I don't think its holding enough water to make a difference. Its likely that its completely consumed by roots.

[Weedhound]

It does matter because there is ferts and fert salts sitting in the medium and it's in constant contact with your roots....mine way outgrow the buckets also but I still get the problem. Use RO or distilled water to rinse through them....check the runoff of what you get out of each basket.....both ppms and ph. Rinse them through several times....ro or distilled ph correct water only. That's how I do them usually excetp at the end of the grow. The buildup is most likely strictly in your medium.

[dejayou30]

Makes more sense now. I'll have to pick up some distilled water at the store tomorrow or something. So what is the technical problem that I have? Just too much build up in the medium or is it some kind of deficiency caused by that?

[Weedhound]

Well what I found with mine was that there would usually be 200 -300 ppm of pure fert sitting in the medium and I think it's causing reactions with the roots like nute lockouts and overfert despite the ppms of my solution being normal. (at say...1200)

For instance....too much phosporus (or something I can't remember exactly which) will lock out potassium and I kept coming up with k defs in my plants even though the ph was fine and I had tons of Bloom ferts available to the plant. Along with your ferts are the fert "salts" and I believe these cause the biggest problem......high salinity can and does cause lockout of several different nutes. I also found several times that along with several hundred ppms of ferts in my rinse the ph would be off....water going in at 5.6 and coming out at 6.2 for instance.....god only knows if that causes its own problems or not since 6.2 is still considered normal.....but for all I know the ph could be worse with build up than I am seeing in the runoff.

Also known as "toxic salt buildup" .