Help! I'm almost out of weed and the leaves on my resupply grow look like this!

[cosmas]

I've had this problem since nearly the beginning of the grow and can't seem to get it worked out - I'm in week 5-6 of veg and it's getting worse. Lower leaves seem to be more affected than upper.

I'm growing white widow from seed in a dwc/bubbler setup (good airstones and pumps)
1.5 " rockwool cubes (now dry) in meshpots with clay pellets
Distilled water, changed every 1-2 weeks, nutes at 500 ppm
temps max at low-mid 80s daytime and min in the high 60s-70ish at nighttime.
230 watt HPS 18/6 (with four 24" agrosun vertical flouros along the sides)
pH 5.7-6.0
humidity 20% (best I've managed - I live in a near desert)
4 plants in an 8 gallon reservior - each plant has the problem
I've examined the leaves with a loop and have seen no bugs

The nutrients are kind of old - I'm using Dynagrow that I bought about 4 years ago. I'm wondering if some of the nutes have locked due to aging. I really don't know if that even happens or not....

This is my 3rd grow - 1st with WW. The first grows (Blueberry, C99) were successful and uneventful. Any advice is appreciated!

cosmas Reviewed by cosmas on 12-29-2007. Help! I'm almost out of weed and the leaves on my resupply grow look like this! I've had this problem since nearly the beginning of the grow and can't seem to get it worked out - I'm in week 5-6 of veg and it's getting worse. Lower leaves seem to be more affected than upper. I'm growing white widow from seed in a dwc/bubbler setup (good airstones and pumps) 1.5 " rockwool cubes (now dry) in meshpots with clay pellets Distilled water, changed every 1-2 weeks, nutes at 500 ppm temps max at low-mid 80s daytime and min in the high 60s-70ish at nighttime. 230 watt HPS Rating: 5

[stinkyattic]

You need to be adding calmag plus if you are using distilled water. That doesn't look like a 'classic' calcium deficiency to me, but there's no getting around the fact that you need plenty of Calcium that is missing from distilled water.
Those spots actually resemble a K def. Something weird is going on with your nutrients. But start with the CalMag Plus, and look at options for hydroponic-specific fertilizers while you're at the shop.
Next time you buy nutes, I VERY highly recommend the Canna Aqua A+B, whcih I run in hydroton with plain TAP water haha and is VERY VERY forgiving. I don't even have to play with the pH because it comes buffered.

[Weedhound]

And I'd buy new nutes tomorrow......

[cosmas]

stinkyattic,

Thanks for the advice - I had avoided tap water because the water here is extremely hard and I was concerned about excessive Ca++ and Mg++. I have a softener but then the water would be Na+ laden. I'm thinking that I may start using a 50/50 blend of tap and distilled - or just stick with the distilled and add the CalMag plus.

Regardless, as per your advice (and weedhound's) I'm ordering new nutes now (will try the Canna Aqua A+B).

I'll post picks of the progress -- thanks again!

[stinkyattic]

mixing tap and distilled is a pretty decent solution to that problem if you can recognize the symptoms of ca def vs other nutrient lockout.
Keep and eye on the pH, since it tends to rise over time with RW and hydroton- it seems to take 4-7 days to stabilize after the system is first 'wetted' and that can contribute HUGELY to a high pH problem.
You're right about the Na+.
And you are also correct in your labels of the oxidation states of the metals... haha cool... nerds = woot. (I'm a lab rat by profession, analytical chem specifically)

[cosmas]

I'm happy I remembered to annotate those oxidation states correctly and didn't embarrass myself! I went medical but each of those ions are still a part of my working life - though I can't pretend to even swim in the same sea as an analytical chemist. (Although I dabbled in some research in the NMR spectroscopy part of your field for a little while.....)

PS: The Canna nutes are ordered and on the way!

[the image reaper]

yup, your plants want calcium, from those pics ... get your water from your outdoor faucet, doubtful if it is plumbed thru your water softener ... not to brag about MY laboratory capabilities, but I do make some pretty damned good sun-tea ... :jointsmile:

[stinkyattic]

not to brag about MY laboratory capabilities, but I do make some pretty damned good sun-tea ...

You're hired. The coffee at the cafeteria is wretched.

[cosmas]

I'm still waiting for the Canna Nutes (should be here this week) but the addition of the un-softened tap water has done the trick. A few days after adding it several fresh, spot-free green leaves started growing. The plants are now flourishing.

The water here measures 1250 ppm out of the tap and is loaded with Ca++ and Mg++. Nasty to drink though...

Thanks for the advice everyone!

[stinkyattic]

Haha sounds like you could bottle your tap water and sell it as a low budget calmag knockoff, lol. That's pretty stiff EC! When you make a cup of tea with it, does the spoon stand up?