needing help with a pH issue in pro mix

[downtimej]

Ive been running gh fora nova in pro mix [email protected] going in and in runoff and it works well for some strains and not so well for others. Ive noticed early yellowing and some lockout issues with ph fluctuation issues. Im switching to cannas substra lineup and want to get some better advice on proper ph. Way too many varrying ideas online, was hoping someone on here would have some more rock solid advice. Thanks. Ps. 5g warrior pots, 79 lights on 72 lights off 45%humidity and ph drifts to 6.4 within 24 hrs.

 

[downtimej]

Also, i use tap water" no room for ro at this point" and have followed gh recommended feeding schedule for expert drain to waste, will switch to cannas normal feed schedule for subsra hard water...feed water feed water, dont get nute burn, maybe just a dot on the tips, should i use a lighter feeding more often like feed feed water at say 6 for a ph?

 

[BobCajun]

I'd recommend pH 6.5. I know that's higher than most recommendations but looking at a chart of the various nutrient availablilities at different pHs it was clear that phosphorus availability drops right off below 6.5. I wouldn't worry about micro availabilities, since most nutrient products use chelated micros anyway.

About your water, just get a ZeroWater filter. Cheap and takes it down to 000 ppm. Besides, you can also use it for your drinking water. I also had a pitcher with the carbon type filters, like a generic Brita type filter. I had just bought a new filter for it shortly before I got the idea to get a ZeroWater and it said that it also adds calcium and magnesium to the water, or maybe it was just magnesium, can't remember. Anyway, what I do is take the ZeroWater and put it through the carbon filter pitcher because 000 ppm is actually not that good to drink because it's too low in minerals. You can get the ZeroWater units at Walmart and other stores. It comes with a TDS pen, which you'll need if you don't already have one.

 

[downtimej]

Thank you for replying the phosphorus that makes sense seeing as how my plants flourish in veg and show signs at the 3rd or 4th week of flower I'm going to check out that zero filter online right now and see if it's feasible for my operation thanks again.

 

[downtimej]

Nope 0 waters definitely not going to work I need to produce too much water I guess I'll have to go with an RO system in the future but for now the substra hard water version is going to have to do

 

[downtimej]

Considering the pH drift in pro mix would it be more feasible to adjust my PH from 5.8 in veg up to say 6.2 in flower? As I said in the last post my girls are beautiful all the way through veg and through their stretch in flower, it's usually at week 3 of flower . They start exhibited deficiencies. These 2 pics are from a veg room and a plant in 1st week in bud room, the previous pics are plants at week 4.5 of bud...

 

[BobCajun]

Considering the pH drift in pro mix would it be more feasible to adjust my PH from 5.8 in veg up to say 6.2 in flower? As I said in the last post my girls are beautiful all the way through veg and through their stretch in flower, it's usually at week 3 of flower . They start exhibited deficiencies. These 2 pics are from a veg room and a plant in 1st week in bud room, the previous pics are plants at week 4.5 of bud...

Yeah I'm sure that would be fine. I know what you mean. The pH always seems to go up after you put it in the pots so might as well start out low. I guess my idea about using 6.5 might be unwise because of that. But what makes you think you're getting lockout issues? Maybe it's something else, like the light being stronger in the flowering area. I've moved plants from CFLs to HPS and the leaves got almost all brown and dying, even though nutrients were proper. HPS can burn your leaves right up very easily.

About the ZeroWater, you could actually just buy the replacement filters and drop one or two into the water tank and they'll absorb the salts like overnight. At least I assume they will. Didn't actually try it that way but the way the ZeroWater containers work is that the filter sits underwater after the water goes through it and keeps absorbing stuff over time. An RO system probably wouldn't work much better if at all and costs a lot more. They also waste a certain amout of the water because it has to keep rinsing off the membrane with some of the water and drain it to waste. The ZeroWater doesn't work that way. It's ion exchange pellets. There's no waste involved. Maybe you can find a high volume ion exchange system but I doubt you can get the pellets much cheaper than just buying the ZeroWater filters. Haven't actually looked into it.

 

[downtimej]

Im not sure of anything at this point, but i have 4 1000w hps in a 12 x 12 room about 18-24" above the canopy. Never noticed burn, but i do occasionally get bleaching at the hot spots. Im assuming ph problems because of the signs on the leaves.certain strains, like the white lavender in the pics above star to yellow in wk 3 of flower, ive boosted with a little extra n and calmag to no avail. I could be way off too. Not enough nutes? I feed,water, feed at regular strength throughout. Maybe not enough flushing? But when i water its straight ph water till runoff. Im picking up a bluelabs ph pen for soil today so i can check my root zone ph and ec levels and will post the results. Also when i feed/water, i usually use about 1.5 gallons to a 5gallon container. It takes 4-5 days to dry out enough to water again but anything less and i dont get runoff. Im going to start adding 20% perlite to the promix to air it up a bit.

 

[covert222]

I know I'm going to be attacked and abused for this statement but tap water in general is just fine for your plants. Unless you have some super shitty water that's unlike any that I have ever seen. Now come forth with the slew of comments about the micro herd and chlorine and tds and all that jazz.

 

[pseudobotanist]

A reason you're having ph fluctuations could be due to overwatering.

Remember that during the day it's normal for your ph to rise, and at night for it lower

Yellowing could be due to high levels of PK.

To better control the ph in your medium o would add one tbsp of dolomite per gallon of soil that you're using. Also consider adding hydroton (calcinated clay). Look up al taplas soil recipe to see why I suggested these 2 things

 

[downtimej]

Thank you sudo Bob, after closer observation I believe that I am over watering and underfeeding. 1.5 gallons/ 5g warrior pot is taking way to long to dry out and feeding every other watering is coming to 1 feed /9 days which seems to be starving the plants in straight promix...im going to start muxing in a good amount of perlite 20% or so, raise my ph up to 6-6.2, light feed schedule w/ever watering and a good flush every 3rd watering....

 

[driel]

I'm curious to know if changing your promix mix is helping in your current grows? I've been having a hell of a time with leaves dying and it taking too long to dry between waterings. I had a couple of clones I was experimenting on by trying pH 6, 6.3 and ph6.5 and all 3 started yellowing week 5. I've added additional dolomite into these mixes so it would make sense that pH should no longer be an issue in late flower from the peat moss becoming more acidic. In fact, all of these plants grew extremely vigorously in veg and soils were dry after 3 days. My next move is mixing in more perlite like yourself. I think some of my plants are just not getting fed and it's not drying quickly enough for me to get them more without risking mold on the roots.

 

[downtimej]

I started mixing in about 30% more perlite into my promix, started clones at 5.8ph -adjusted to 6-6.2 in veg and 6.2 thru flower and last 2 wks of flush at 6.5 and things have never been better...the biggest difference maker was adding the perlite. The soil drains much better and actually dries out. Im back to watering every 2-3 days. My ph issues actually came from a cheap meter that wasnt reading consistant. I bought a blue labs soil pen and bam...ph issues solved...

 

[downtimej]

Start with perlite to increase drainage, and make sure your ph meter is of good quality, the extra perlite also helps to buffer the ph in promix and helps tremendously with the drift..

 

[downtimej]

I also switched from feed water feed to a feed feed water schedule...feed water feed seems to starve the plants when running in drain to waste systems..

 

[driel]

good to know, I'll be picking up some more perlite soon.

 

[thumper60]

always want a little food when watering promix,dont let plants get to to dry.think hydro when working with promix.try cutting it with coco I think u like