PadawanWarrior
Well-known member
I thought this was K deficiency but I've been watering with a crapload of potassium sulfate for weeks and it isn't improving. It's organic soil. This is starting to bug me since I can't seem to figure it out.
Help: Yellowing Edges.
- Thread starter PadawanWarrior
- Start date
PadawanWarrior
Well-known member
I have well water so it has plenty Ca. I've had issues with too much Ca locking out Mg and K actually. So my thought was the Ca was locking out Mg and K since it kinda shows signs of both. I originally was adding Epsom and didn't notice any change so then I tried potassium sulfate. I've went back and forth thinking it was Mg then I'd think it was K. The edges look like K deficiency to me but it also has the yellowing between veins so I'm confused as hell now.
I've been adding around a tsp of potassium sulfate to each liter of water when I've been watering it lately since I was determined it was K so it can't be K deficiency unless K can lock itself out. I added some micronutrients today thinking it might be that but I'm stumped on this one.
PadawanWarrior
Well-known member
I'm using dry amendments and top dressing. I was watering in potassium sulfate and Epsom but usually just use plain unadjusted well water. It was around 160ppm last time I checked and 7.9 pH. I checked the soil pH with my Bluelab soil pen and it tested good at 6.3. It's recycled organic soil.
I assume that you’ve used this feeding system before. I don’t know what your amendments are but you’re certainly got either lockout or deficiency and I’m thinking it’s more than likely lockout but you got me where you’re getting the problem from… have you ever thought of using pre-blended nutes for your plants just to see if that changes anything
PadawanWarrior
Well-known member
I've used premade mixes like Craft Blend from BAS but that has a lot of Ca in it and when I use much it starts locking out Mg. I've been using my 15 gal pots with the original soil for almost 6 years. It's been a learning process for sure. This is a 5 gal pot that I used a mix of the original with some peat. It worked great for the first part of the grow and then the pH dropped and it got down to the high 5's. I added some K based pH up and got it back up but the extra K started locking out Ca and Mg it seemed like. So I added some gypsum and Epsom a handful of times and it was happy for a bit. Then this yellowing started happening.
Maybe it's Mg overdose that's locking out the K. Because it does slightly remind me of when I've added too much Mg from the langbeinite and it seemed to lock out K. I don't know, I just thought I'd see some improvements after adding that much potassium sulfate.
You are burning the shit out of your plants. It's showing in the leaves. You need to do what Boo said and do a pour thru and test the runoff. When a person adds too many salts to the substrate the pH drops too low. A low pH will turn the leaves yellow. Do you have an EC and pH meter?
PadawanWarrior
Well-known member
I tested the pH just in case and it was good at 6.3. The pH meter I have is a decent Bluelab one but I just have a cheap EC meter that I've never used.
Just watered with plain water and the runoff ppm with my cheap meter was around 1850. Poured 5 gallons and got it down to around 1400. I'll do it again tomorrow.
Thanks for the input @Creeperpark and @Boo. We'll see if we can turn this around.
Update: I ran 5 more gallons through (so 10 total now). The runoff ppm are now around 400-500. Wish me luck.
Last edited:
BradChremistry
Member
Too much Mn not enough Zn
Mn toxicity
Zn deficiency
Mn toxicity
Zn deficiency
PadawanWarrior
Well-known member
You may be on to something there with the zinc. I thought it might be a micronutrient since the potassium sulfate wasn't helping so I tried adding some Big 6 or TM-7 a couple times but I didn't notice much difference. Maybe it just needs more. Why would you say too much Mn though?
Edit: Just looked at my notes and I've been using TM-7 not Big 6 and that has iron. Big 6 doesn't have iron. BAS had them make it special since their soil seems to have plenty iron. That makes me think it's probably the iron that's locking out the zinc. That would make sense actually. Thanks for your input. I'm determined to figure this crap out.
Last edited:
I wouldn't have flushed it that much friend. I was just wanting you to test the runoff. With a pH of 6.3 you can have a higher EC because salts are slow or unavailable.
I can learn something here and thanks for your post. Let's hope for the best and see how it turns out. Keep us posted.
PadawanWarrior
Well-known member
It's all good. The fertilizer in the soil will breakdown pretty quick and bring the ppm back up. I think I'm going to try and grab some zinc sulfate somewhere. I can do a foliar with it on part of the plant and that should tell us if it's zinc or not. I just want to figure it out. I've already harvested a crop off this plant and have it's clones going so it's not a huge deal but I want to know. Thanks again for your help. I appreciate it.
You are doing a good job friend. This is a good thread for anyone interested in learning. Thanks
PadawanWarrior
Well-known member
I ordered some zinc sulfate last night. I couldn't find any locally and I even called a couple hydro shops. Today I fed it some Big 6 micronutrients which has zinc as one of the 6 and no iron. I'll keep everyone updated for sure.
farmerfischer
Well-known member
Fingers crossed bro...
It looks like classical magnesium deficiency or lockout.
Src.
I can't say more without knowing:
- medium used
- nutrients given (brand, EC/PPM, pH)
- pot size if not hydro
- run-off pH (only the first bottlecap after you slowly run filtered water through the medium, to see if the pH and EC or PPM are higher or lower than those of your medium or nutrients.)
Magnesium deficiency often happens when using filtered water and no calmag or maerl, when the first pre-flowers appear, around the 9th node, in most photoperiod strains.
Last edited:
jackspratt61
Active member
I would suspect high na/k or just high na or k. Without a water test counting on Ca is hunting blindfolded. You have a Ca/P imbalance which can look like many things. As mixes breakdown they create bicarbonates as well which with the added bicarbonates from your well will cause ca uptake issues. Have you tested mix?
PadawanWarrior
Well-known member
It's in 5 gallons of recycled organic soil. Usually just top dressed but some gypsum, potassium sulfate, and Epsom has been watered in trying to fix things. It definitely has parts that look like Mg deficiency but those yellow leaf edges I thought were K deficiency. It can't be though since I've been giving it soo much K and it seems to be getting worse.
My well water is around 170 ppm and 7.8 pH. I know it has plenty Ca since I've had issues with a little too much Ca. The top dresses usually have plenty Ca already and I think added with my water is a little much over time. The runoff was a little high so I flushed it a bunch to try and get rid of some of all that potassium sulfate I've been giving. Thanks.
PadawanWarrior
Well-known member
I definitely have high K in that pot since I gave it a crap load of potassium sulfate. And my water does have plenty Ca. So a Mg deficiency makes sense too. I've been going back and forth between Mg and K but Zn was brought up too so now it's just figuring out which of those 3.
