Its Always Something...

[stinkyattic]

Looks like salting to me too. There's both burn and def symptoms on the same plant.
How much runoff do you get when your nute delivery system is going? In terms of, every time you water, what is the ratio of water in to water running off?
For example, when you are running drip-to-waste, a 10% runoff acts as a constant flush so that anything not used by the plant is constantly being washed out of the medium.
Practically applied, If you pour in a gallon, and nothing comes out (=it is just enough to feed the plant and not flush it), anything that was not used then gets to sit in the medium and possibly react/recombine into molecular substances you DON'T want.
Just a couple ideas to think about.

stinkyattic Reviewed by stinkyattic 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

[dejayou30]

I'm not really sure what you mean stinky. I have a 13 gallon reservoir and when the nute solution pumps in, there is probably a gallon or two left in the res before it hits the max point of the bin when it starts to overflow back into the res. Is that what you mean? I just don't quite grasp what you're asking.

[stinkyattic]

Oh, you're doing flood and drain.
Is the main part of the medium rockwool or hydroton- are you groing in RW slab or in RW plugs that have been inserted into a bed of hydroton?
In slab, I'd recommend a drip rather than flood.
In a HT bed, I'm thinking here. Hm. Whatever else, you will need to clean out your system- Run plain pH'd water through it for a couple flood cycles and see how much the ppm of the res rises jsut from residual crap that was clinging to your HT. Then dump and re-fill the res with your regular ferts at a lower ppm; try 800 since it's apparent that over 1000 was too high for the plants. And you might try bumping up the pH to 5.8 or so- subtle, but if your meter is even a tiny bit off, saying 5.6 when it's actually 5.4, that would at least put you in range.
Another thing that I'm thinking is, what's the plant mass being fed by that 13 gallon res? If the res is too small, and your feeding is even a little too heavy, again you get a problem with residuals. Think of it this way: You have a bucket of marbles, black and white, mixed up about 50/50 b/w (vague metaphor for your nute solution- bear with me!). The plants use the black ones faster than the white ones. Every time your res level or ppm gets low and needs topping off, you add another dump from the original mixed bucket of marbles. But there were already some white ones in there contributing to the high ppm, the ones the plants don't use so fast. So now your new mix is over 50% white marbles, and under 50% black ones, even if the actual # of total marbles in the res is constant (=ppm remains the same).
Ehhh.... that's such a terrible explanation but the meaning is, dump your res regularly, because unless the plants are using up ALL components of the fertilizer at exactly the same rate, its composition changes over time.
Edit: I totally forgot to say, I think a 13 gallon res may be a bit small for the setup, or that you should do a COMPLETE water change in it more often.

[dejayou30]

The first two weeks I kept the same res, but I am going to start doing every week again. My last grow I did every week and I got lazy the first two weeks this time around. I'm due for a change, so I'll flush for a day and see how things are and go from there. Thanks for the advice stinky!

Oh, and my rockwool is the small 1" (I think) cubes surrounded by hydroton and I am feeding ten plants.

[dejayou30]

I switched over to plain water tonight. It started with my 300 PPM tap water and it went to 400 after the first run and up to 420:thumbsup: after the second and I think it's leveled off. I'm going to leave it for the rest of the feeds tonight and change it out again tomorrow and try around 900 PPM with full bloom nutes.

My sister got me Jorge Cervantes's Medical Grow Bible for a late Christmas gift tonight, and I've been reading it non stop. From what I read in there, it definitely sounds like it was salt buildup. Not that I doubted either of you though!

:jointsmile:

[theduts]

[ hi guys just planted 10 white widows in rockwool having ph problems. only socked them for about 6 hours. checked runoff today and its 6.6 i flushed 6 times with ph of 5.5 but it just wont come down.the medium is rw and pellets can anyone help please. theduts.