Just a quick question. I’m growing two autos (RQS Titan and Wedding Cake). They’re in BioBizz “Light Mix” soil, and I’ve been feeding them with BioBizz organic fertiliser (using their products Root Juice and BioGrow).
I’ve been following doses when I water, and the plants look healthy (both currently at slightly difference stages of pre-flower. Both about 45 days from germination). They are growing in a 2x2x4 foot tent under SF1000 EVO 100W Full Spectrum LED Grow Light.
Anyway, my question is about PH. When I water each plant, currently in 3 Gallon fabric pots, I give them each about a gallon. PH going in last couple of times was about 6.3, 6.4; coming out, more like 7.4, 7.5!
I’m also getting EC and PPM readings from run off that are HIGHER than what went in. Last watering, for example: IN–EC: 1260, PPM 663; OUT–EC: 2020; PPM: 1020.
I read variously that this could be salt-related lock-out, but I’m using organic fertiliser (that specifically says I do NOT need to water to run-off… which I’ve been doing anyway, flood to drought., etc)… I’ve also read salt build up is not an issue when using organic fertiliser (hence no need to water to run off).
But does anyone have ideas or advice about what’s going on here? As I say, the plants look healthy… there’s nothing I feel compelled to photograph in order to ask about specifically, etc. But I’m keen to figure out what might be going on here, in case there’s trouble coming.
1 gal into a 3 gal pot is way too much. More like a quart to 1/3 gal for pot size. Not salts so no buildup and no water to runoff. No EC reading necessary cause meter can’t distinguish availability with organics. Salts are all available and must be monitored.
You just need to to follow the schedule with no personal modification once a week and the rest of top offs is water only
Plants can’t deal with current nutrient load. Lights need to be increased for metabolic functions to increase. A 100 watt light is simply not enough for one plant; much less several.
Thanks @Budbrother. How come this is too much water? I’ve read on various sites that watering to about 20% run off is ideal. That’s what I’m doing. That’s wrong? I don’t water often, only when I lift the pots and can feel (or, think I feel) they need more. Is the 20% run off thing only for “normal” fertilizer? Also, what does “all salts are available and must be monitored” mean? How do I monitor them? Sorry, I’m new to this (2nd ever grow)!
Thanks @Myfriendis410! Yeah, I’ve heard that 100w is not enough before. I bought it as part of a package, designed to fit the grow tent (which is small–I don’t have any spare space at the moment). Anyway, this 100w light worked ok last time, during my first grow. It wasn’t a massive yield, but enough for my purposes! My sense of things was that for a more powerful light, I’d need to have a bigger space. This light is pretty new, less than 6 months old. Are there developments in the industry that mean 100w is enough, or is it just ultimately a question of math, ie., of counting (in which 100w is simply never enough)? As it happens the two plants in the tent now are nearly about as big as it will handle. So I’m doing my best under the circumstances.
You don’t wanna wash away the food. Typically you don’t want to water more than 10% pot volume and 5% mid flowering. You don’t want to see runoff, as it’s a different feeding mechanism.
Correct. “Normal fertilizer” = salt based foods (instant availability) build up salts and leads to issues that requires a flushing. This is why you water to runoff like you’ve been reading. It’s like a mini flush to remove excess each time. With organics, food isn’t instant availability and requires breakdown by microbes.
Answered Above. Since you’re not using salts, you don’t monitor the EC. The meter can’t distinguish between available and unavailable nutrition. Every time you water you release more nutrition. That’s why you feed once a week according to schedule and the rest of the time you only add plain water.
Oh, just one last thing: do my PH readings make sense? 6.3 in, 7.5 out? Naturally, now that I know I don’t need to water so much, I won’t be getting run off readings anymore, but does that sound like cause for alarm?
My 3-gal bags are not filled to brim (top dressing available).
My watering routine is either lift and determine light or wait for leaves and stem droop. Which is visibly different from end of day “tired” leaf only droop.
I am an over water type grower, using more perlite and restraint.
Jacks RO being used with my city water (7.3PH and >50ppm).
My dehumidifier water mixes well with the Jack’s RO and city water.
Regarding, Your original post question 1 gallon water in with run-off is just washing your nutrients away. 32-64 oz is all I use and get a trickle of run-off.
regarding PH 7.5 out…
FFOF or KIS water-only soil does the same, unless washed out/down.
“Buffering back up” is a design (?) for some soils.
Nutrients flushed out, no fun.
FFOF will also “crash” after week X (4-7), IME.
Some adjust, some dont.
PH pen required
FFHF soil is closer (5.5-6.5) and has not crashed, yet.
Sounds like the soil is buffering it back up. You want this. This means the Ca levels are adequate. The microbes will raise or lower the pH naturally within reason to suit the plants nutritional demands. Just don’t let the pots dry out completely. This will cause the pots to increase pH. Organics requires you to maintain a low to moderate amount of moisture to maintain function. Think about if you were to go outside and dig a hole; you wouldn’t get too deep before you hit moisture. This is what you’re aiming for, still moist and microbial functioning.
Salts and organics are not the same. People don’t help when they try to interject with salt growing methods. I stay outta salts business, and I wish people would stop “helping” in area without the knowledge and experience to properly guide. This isn’t directed to you but to all those people that confuse the situation.
It’s normal to get higher ppm out than in if the soil has plenty of nutrients in it already. That’s what you’re seeing.
@Budbrother explained nicely how pH buffering works in soil. I’m using Foxfarm Ocean Forest soil and, even though I pH whatever liquid I’m pouring on the plants to 6.5, my runoff ranges from 6.9 to 7.3.
As for watering, judging the need by gauging the pot’s weight is used commonly by growers on this forum. Nothing wrong with that tried-and-true method.
I use 3-gallon grow bags too, and, depending on the plant, need to give 1.4 to 1.7 L to get 20% runoff (i.e., 280 to 340 ml) from each one. Consequently, it’s hard for me to believe that your plants require 1 gallon (3.8 L) to get 20%, i.e., 26 ounces (780 ml). I’d bet you’re getting much more.
As @DEEPDIVERDAVE (and the instructions printed on your nutrients) pointed out, watering to runoff is unnecessary for you. Organic fertilizers contain no salts to build up and require flushing, so you’re washing nutrients down the drain for no advantage.
I was having this issue in coco. Turns out though my fabric pots were sitting in trays and the salts were just accrued at the bottom. Once I got the plant on a riser and flushed it brought my out #s down. Just a thought.
Hi @Venturi. Yeah, 3.8L is too much. I work in metric so I’m using the word “gallon” loosely, and obviously not super accurately. That said, I HAVE been watering about 2.5 litres per plant, per time. Which, although not the 3.8L you describe, sounds still like far too much for plants feeding on organically enriched soil. I’ve been confused by info I’ve read in terms of run off… I just assumed I needed to. So I’ll adjust: less water, but more frequently, to keep the soil moist as @Budbrother recommends.
