Locking it in

[leum]

Fourth season - need help perfecting my grow.

This little lady is a ten-day-old Afghan Kush Ryder. Concerned about pale spots between veins. Also white tips on beginning third pair of leaves. A decent growth rate by my standards, but want to dial in a perfect grow every time.

The system. 5 gallon ultra oxy pot (air pot knock-off) filled with Canna Terra. Before planting, soaked with distilled water plus Canna Vega, Rhyzo first week nutes plus Cal-Magic (4mls/gallon), pH=6.0. Watered by drip from overhead reservoir through tropf-blumat auto-watering system. 180W Blackstar Chrome LED lamp is 24" above top of pot, on for 24 hours. Added small blue fan thinking pale spots might be heat stress. Current temp is 80F, RH=44%.

Hope I didn't forget any details. Read lots of self-diagnosing material. What can I be doing better? Thanks!

 

[Gatorbackbob]

Maybe bump the lights down 20/4 see if the dark period helps out, I'm not familiar with the medium, I'm guessing coco or another soilless mix? It looks like a deficiency, but not sure which, maybe magnesium, but not sure. @Waira what's it look like to you?

 

[Waira]

Leum, Bob-- Hmmm, symptoms are kinda indistinct at this point, but I do see some edge and tip curl- usually a temp/RH/light intensity issue; light looks very red, is bloom spec burning as well as veg? Even at 24", it might be too much for it just yet..... good soil, nute's,.. 6.0 is your inputs pH?... In-pot measurement is even more important, but this early on, it's hard to believe it's a pH issue in there, unless the soil was off to begin with. Too bad you don't have an Accurate 8 soil pH probe handy, that would answer some things right off the bat... how much are you feeding, like 1/4-1/2 strength? Constant input right?... Again, between the soil and young age, a defc. issue is unlikely, so actual soil pH and light intensity are the next best suspects... Do you still have soil from the same bag? You should at least test that, before anything else,... make a small pot up, and try this improved run-off test... no r-o test is very good, but this one if followed will eliminate some error sources- https://www.autoflower.org/threads/...-testing-and-ph-estimation.41733/#post-928975
...let know what you got,..

 

[leum]

Thanks, Gatorbackbob. Yes, it's a peat-based soilless mix. Read great things about it, so gave it a try.

Thanks, Waira - I don't have a soil probe, but the old rapitest is looking pretty blue with soil from the grow. Alkaline, maybe 7.2. This happened with soil in the past, but I don't think I've checked the Canna Terra. I'll have to read how I dealt with it. Can I re-pH the reservoir to a lower pH to compensate? It seems to be just beginning, and the plant still seems strong. Do I need the run off test, or just figure this is the problem?

You're right, the lamp does have bloom spec burning as well as veg. It's seen a few seasons of use. Gotham sold me on it as an all-around lamp, and it has performed flawlessly. Went with full strength nutes right off the bat on the advice of grow shop owner. Thinking distilled water needed more Cal-Mag and micros. The tap water here is hard enough to cause build up on bathroom fixtures, so using distilled instead. Could think about a new lamp. Local shop is HTGSupply. They sell a house-brand LED that looks fine, but haven't read much about them.

Thanks for reminding me to check the pH of the soil!

Edit: Water pH was higher than when I first pHed - 6.9. Brought it down to 5.5.

 

[Waira]

sure, use a pH adjuster product, Up or down as needed,... 5.5 is too low for soil,.. about 6.5 is the sweet spot, but keeping it stable in your res' might be difficult unless the nutes have self buffering,... (like Advanced Nute's)... DI/RO water is fine for res water, but you'll need Ca-Mg added, and again, the nute's may not do buffering (RO/DI has all the pH buffering CaCO3 removed from it)... you can use a blend of dechlorinated tap and DI, to about 150ppm,...
... even with nutes, it's still alkaline? What's the water source?

 

[leum]

Hand watered with re-pHed nutes, and looks like she's already perked up. Fingers crossed. dH2O is bottled from the supermarket - whatever brand they have on hand. Would it be better to use bottled spring water? Tap here can't be good, as my toilet bowl frequently reminds me. Thanks again!

 

[Waira]

Spring/drinking is fine too, most are nearly as low ppm as DI/RO... Yeah, if your tap is brutally hard, it's more of a PITA than it's worth to deal with! Have you much demand for it? A smal RO unit might be a good thing to have, save $ down the road,.. also, those self fill machines and a 2-5 gal jug is a great option too, cheaper than prebottled stuff as well,...

 

[leum]

Little demand, just one plant at a time, but I could use better drinking water myself. Beer is getting expensive.

 

[Waira]

And painful sometimes!

 

[leum]

Lookin' good at four weeks. Just switched to bloom nutes. Using bottled "drinking water" at pH = 5.8. Appears to be distilled or purified with buffering added back. Still see a little spotting, but strongest plant so far at this stage. Next time, be more careful with pH. Thanks again!