The day I learned that ppm was calculated from EC I changed over. Don’t need more meaningless confusion, lol!
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Some redundancy in this post, I’ll edit or delete it if you want.
A diy ebb flow that floods a “tray” with small nursery pots? Could use a tote that will nicely fit a “cement mixing tub/tray” (or bus pan) on top of it’s lid. But I’m sure you’ll find a hundred ideas searching.
The ppm / EC thing. I’m always talking about this. It’s a persistant cause of…“confusion”, to some degree. I know you (FE) likely already know all this…
When you mention 100ppm of “x”, and then mention two elements “Ca”(calcium" an “Mg”(magnesium), it makes it sound like you’re going to add 100 parts of something (Ca, and or Mg) but that’s not what’s happening. You’re just adding enough “salts” to change the electrical conductivity by 0.2 mS. Every 0.1 mS is “equivalent” to “50ppm” on the “500 scale”.
But then, when you show a screenshot of greenleaf’s “elemental nutrient calculator”, you are really showing the actual (estimated/calculated) elemental ppm of each element in the proposed nutrient solution. (It’s awesome that greenleaf provides this tool, by the way.)
The conversion scales are different, depending on the manufacturer/region of the product; equipment/meter (ie: EC meter), nutrient/fertilizer solution, feeding schedule, etc., it just depends what “x” company uses. EC is universal. All the meters measure EC, then they just do math of “EC x 500” (for example) 0.7 EC x 500 = 350"ppm". 0.7 EC x 700 = 490"ppm. Two meters at the different “scales” will both read the same solution as 0.7 EC, but will each display different “ppm” numbers.
Another solution, mixed with completely different inputs (random salts, or just the same ones but it different ratios) could also be mixed to the same EC, yet have unusable contents/ratios.
Oh - never mind, you got it. Haha. Well, I kinda like this topic.
If/when talking in meter “ppm” I use 500 scale because the math is easier/more intuitive.
But the “ppm” measured in soil tests is actually elemental ppm being measured, not an “EC conversion”.
There are meters that measure a specific element’s actual ppm in solution. Scienceinhydroponics has a short video showing one on his youtube channel.
My “fancy” meter, measures EC like all the rest, but it displays any of the EC units I want, auto switches from mS to uS when under a certain threshold, and can display any “conversion factor” of “ppm” units I choose too (x500, x700, or x any number I want).
I still have a sticker/note on one of my meters saying “1EC = 1mS = 1000uS”, and I sometimes get confused still. I like the uS unit because it’s a smaller unit to watch for changes when I mix up fertilizer, and it makes trying to change from “EC” to “ppm conversion equivalent” a bit easier, if needed, easier.
Some good links I had on this (EC, TDS, Manufacturers, etc.) if anyone wants to scan over:
Apera - EC, us, ms - How to convert
Apera - EC/TDS in Hydroponics
Jack’s Nutrients - Measuring the Strength of Nutrient Solutions
THC Farmer - Manufacturer’s ppm scale info
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I wish it were that simple, but the calculations for nutrients are all still in elemental PPM. 
But indeed, I’ll be using EC for measurements of nutrient solution. 
Yessir. I’m most likely going to use 4" rockwool cubes but indeed. There are several options for the tray, many of which are quite a spatial compromise for the 23" x 23" I have available in the tent.
But the good news, it looks anyway, is that I finally have a MegaGarden en route!
I’ve had some difficulty getting one of those, but it’s 22" x 22" flood-drain and one of the only commercial options that seems designed for a 2x2. I’ve found several old grow logs of SOG setups exactly like what I’m trying to do.
@Nitt I appreciate the resouces. I actually have been starting to plow through all the Daniel Fernandez content I can find. I watched quite a bit a year ago but refreshing things now that I have some more comprehension is beneficial. Additionally been finding guidance in my chemistry textbooks. I have constant pangs of regret not paying any attention to chemistry when I was in school.
Last year I spent quite a bit of time in front of a spreadsheet computing elemental ppms, and converting to-and-from elemental ppm as I calculated quantities of dry and liquid ammendments for my living soil. At this point I readily speak that language and have a good (I think anyway, this is where Dunning-Kruger effect would bite me in my ass) handle on macro/micro nutrients and their effects and quantities to be expected in soil. Hydro is different, sure, but I find some comfort in using familiar knowledge.
The detailed elemental calculator is one of the reasons I picked MC as the fertilizer I used in my 2022 outdoor grow. Additionally, my soil testing has led me to appreciate the formula ratios better than I could in '22.
Having a meter that outputs PPM, indeed initially misinterpretted as you read - as somehow measuring solution elemental PPM. I thought, “sweet, that’s nice I can confirm my calculations.” Only to find, of course, that it can’t do that and just scales the EC measurement to produce an estimate of specific dissolved solids. As Daniel says, “NO TDS.” Of course, I’ll still look at my hypothetical nutrient ratios and quantities via elemental PPM, but I won’t be measuring them that way. EC from here on out.
I appreciate that you “have my back” so to speak on this stuff and don’t hesitate to post these things. A good chunk of the reason I post so many of my thoughts are so I can have some checks on my logic and not get too far off the rails. Thank you!
I felt like it was a theme in my outdoor living soil grow of generate a hypothesis, incomplete conclusion or even WRONG thought, a few posts later learn what’s actually happening and change course on that thought. I rather enjoy reading back on those evolutions, I can see the vulnerabilities in thinking, of which there are several. Additionally, typing out those thoughts in real-time certainly clarifies the thinking. I’m embracing being wrong on the internet. And it’s working 
Life lessons I feel a little late to the punch learning now at 37.
Cheers, and I always appreciate the input. Have a wonderful day guys, time for me to get my ass to work!
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More lessons learned this morning. Lost a seedling 
I just pulled the plug out before I took a picture but I have been over watering and hadn’t noticed because the sponge texture of the plugs. They hold on to an appreciable amount of water. Anyway I had a bad mold/damping off victim. Immediately removed it, misted peroxide on all the others and the inside of the tray. Shifted the lid about half an inch to get more air moving. Whoops 
I picked up the 3" rockwool cubes, I think it’s getting to be time to pop them into those. Good chat with the guy at the hydro shop again this time about cloning. I’m as ready as I can be.
Wondering if I should chuck the plugs that haven’t sprouted and start some other beans…the real question would be what. I’ve been thinking about the Runtz x Sour Bubble freebie Tony Green mentioned in some random post somewhere. Or just proceed as is and take all my licks before I risk other beans to my learning curve.
EDIT: Idiot or not I’m doing it
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Guess what arrived today?
Ahh yeah 
I think it’s going to be a busy weekend. This is the order from GroIndoor.com Not a scam, but certainly unclear communication that this way going to be drop shipped from Hydrofarm. Coincidentally, the second unit I ordered from Amazon on Monday will show up tomorrow. Impatience got the best of me, now I’ll have two. I don’t know if I’ll return the second one unopened or just keep it around…
To be clear to anyone reading this: I did receive the order from Groindoor.com the timeline was not communicated well so my impression of ordering with a 1-day shipping time was really more like 2 weeks. There’s two holidays in between I’m not upset but wish the shipping time estimate was a bit more accurate. I may redact some of my earlier wording
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Now I feel like an idiot doing it the way I did
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We all live and learn!
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Speaking of living and learning. RIP to two more seedlings. This time, due to thirst.
Since the mold issue of 2 days ago, I hadn’t watered the sprouts anymore. Water now refers to 1L distilled water + 2mL Sensi Cal Mag Xtra pHd to 5.6. Yesterday morning I pulled some plugs out, there was some moisture, I let them go. Today two are almost certainly deceased. Plug pull reveals totally bone dry this morning. I should be on America’s Most Wanted Criminals for the capital crime of serial plant abuse. I should have checked them last night but I didn’t. We’re down to 3 sprouts of 907xShiskaberry and 5 907xNL1. The gonners are still there, on a hope and a prayer.
The bit of hunger they show hopefully will be sated by a fresh dousing of cal-mag water. I’m learning about the new setup for sure, and these new sponge plug things. First of all, the seedlings sitting at a steady 85F hasn’t happened before. So they dry quick with a little airflow. Second of all, I think the ACI seedling tray has inadequate ventilation for this stage of growing, I’m taking it off. Third of all, it’s really hard for me to have any real clue how damp/dry these plugs are. I’m so used to seeing the distinct color/texture change of straight coco or peat, this is really throwing me for a loop.
In other news, the Runtz x Sour Bubble have all shot roots out and been planted. They are there on the left now.
Let’s see how this goes. Should I lower my light or is it fine? Photone on my Pixel 7 Pro is indicating 400 PPFD on the tray. I think the plants are responding fine (not leggy, short and stout) but half my plants are dead at this point so my “think” may not be so hot
My light cycle is 8pm to noon the next day. So actually only 16 hours. I must have brain-deaded the numbers there I intended for 18 which would be until 2pm. I blame the Panama x Malawi I’ve been smoking on the weekends. Anyway, I’ll check back on them throughout the day because it’s now the “weekend” for me.
Have a great day guys.
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Morning @FieldEffect
My last several grows have started, worrying Less about ppdf values and ensuring the actual Leaf Temp is close to but not Hotter than the room.
14 cm gap below and the leaves are at 74F. Thats the latest Start here in the Peoples Republic of Ontario
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To choose a house, i test first the water quality ^^ I’m a bit maniac on this side, now a PH 5.5 is really too acid for coco and will give a hard time to the buffering of the medium. It’s not the fiber of rockwool or clay balls that can resist everything, but an organic coir that degrade past a certain point of acidity. But yes nothing unreasonable, it’s not 4PH with gas emissions or 12PH with some funky smells as far as i understood ^^
For the flushing, we are supposed to do it on a regular basis. I flush my house once a year and my circuit length maybe once per two years (start of the line so, it’s done in 20 minutes). When you see and smell the mud that come from it ^^ the first time … you’re glad to keep it clean.
I consider Rockwool as one of the most oxygenated medium yes, so to don’t use this advantage would be a waste for me. It’s not complicated, just the fact to use drippers with rockwool by example is enough to lead to the right way on the O² dpt. Coco is full of O² too, mastering dry cycles in this medium always produce crazy roots.
On drain, i’m quite extreme. I use closed loop generally only for veg and mothers, it’s very rare that i don’t flower with a DTW. I’m very picky with traces of nutes in the final product. You can even make a cool test without even spending cash in a lab.
You take the same weight of buds, one sample from a bud flowered in closed loop and one flowered in DTW with flush. You place the two buds in enough clean water to cover them, then you let infuse in changing the water each day in collecting the soup, until the water is clear. You can feed two weeks young clones or seedlings with the water coming from the closed loop buds ^^, and they starve in less than a week with the second soup.
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Assuming you measure this with IR gun? I can do this, actually have a thermal camera.
What the veg side looks like overall. Not surprisingly the dark stuff that’s not wet is warmer than anything else. There’s an appreciable amount of thermal energy in the light itself. The lights themselves are the hottest things at 87F or so, followed by the tray and heatmats at 85. Dirt plugs, freshly watered at 70ish.
Sure. I was referring to preparing solution for rockwool, which seems to request a pH between 5.5 and 6.
I’m sure. I flushed my hot water heater out when I was renovating the utility room/pantry last week. I’m looking forward
I see. This is one of the reasons I like the idea of rockwool. It’s also appealing in its convenience indoors, the blocks easily stack, it’s tidy and clean to store.
I’m quite curious about everything I hear about residual nutrients. This is an intriguing test. I switched to organics to see if I could perceive a difference outdoors. Indoors obviously is a whole new ballgame and am doing hydro because of the plant density and cleanliness. I am convinced there is one but it is really difficult to determine without an A/B test. Maybe I’ll do that this year. Run the same cut organic and synthetic in the same conditions and evaluate the result.
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This is where the Dimmer truly shines.
You get to turn the Power consumption Down, while you Increase Intensity, with Proximity
ps, You r Correct, i have the $20 temp Gun. Perfect tool @FieldEffect
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I’d recommend a small scale to weigh them. In my experience these things usually can hold one or two teaspoons at most before they start to go pathogenic; it’s worth figuring out where the sweet spot is so you can take them out and bottom-water once a day without them going too wet or too dry. Usually mine shed 4-5ml of water a day. I start them out at 12g, dry enough that you have to squeeze them out after soaking them, and the next morning at 7-8g they’re usually starting to dry out but with a core of moisture at the center keeping the seedling going. They’re 4 grams bone-dry though, so two days is enough to dry them out - it definitely requires some maintenance.
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Good morning and weekend!
This house water flush is something I need to check out…. Sounds like a no-brainer. We have these old pipes though… don’t want to give my house a stroke 
Little starter cubes like this and rw are so hard to overwater, just don’t leave them sitting in it. Don’t treat them like little jiffy starters. At this stage I’d probably be dumping water in the tray every day or every other, let them soak until full capacity and dump excess.
Edit: @Cormoran gave a much more detailed explanation
400ppfd for seeds is in the “pushing” it realm, 200 works well for sprouting and rooting in my experience.
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I’ve been using 17/7 for a couple years now.
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Yeah… we’re gonna need to be seeing more predator vision here pal
Though all visions are looking pretty promising 
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OK, so I’ve done a few things.
Lowered the light to maybe 12" and turned the intensity down to 300ppfd. Humidity dome has been off for 24 hours. I watered well yesterday and again today. My dryback victim seedlings are indeed fully dead. The leaf temperature went down a couple degrees to about 75F.
The plugs are really difficult to remove from the tray to weigh individually, but this is great knowledge @Cormoran and @NoCal. I need to get a more accurate method of dispensing water to them, a 1L water bottle just splashes all over. I’ve got a scale. I’m wondering if perhaps the accuracy only matters if I’ve got the dome closed, and the drying is fast enough with it off that there really isn’t a mold danger zone anymore. In any case, it’ll matter for clones. It’s good to get a feel for this stuff now.
I am seeing better results without the dome. I know they needed water this morning, and the seedlings look OK. The Runtz x Sour Bubble is starting to pop out, several of the seeds are crowning.
For @Not-Notjosh and @MissinBissin the predator can return at any time.
Nice way to check how my homebrew lighting solution is doing:
And a seedling pic to check the temps:
@Nitt I think the 16/8 cycle is actually fine. I did 14/10 cracking seeds the last two years because that was the exterior photoperiod when they went outside early May. I didn’t want anything to get shocked into flower early.
I now have two complete MegaGarden setups. That got an eyeroll from the household governor to see on the porch. Still debating on keeping the second unit. Getting the first unit setup today. Also finalizing and flushing the RO system today. My anal-retentive nature (especially plumbing and electrical) leads to things taking much longer than most sane folks.
I’m going to build a platform for the MegaGarden to ease draining into a pan for flushing and rinsing the reservoir. I think 4-8" is the ideal range.
It fits beautifully. Here it is tossed together for a fit-check:
Happy Saturday!
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You are Progress in-Motion @FieldEffect and its so nice to see things Happen.
Great work all the way around my Friend. Leaf-Temp is just another tool in the Box.
And you may have a Black Hole for a Tool Box, given your line of Work.
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maybe send back the MG to appease the governor, and pick up a PAR meter? 
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