I know I've got a mag deficiency

[jimnut]

Hey GC, I was wondering if I could get some help. I'm growing 4 plants in FF Ocean Forest with an MH 250. They're all about in their 3rd week of veg growth. I've been feeding them some roots organic buddha grow and they seem to be doing ok. The only problem is that two of them are showing a magnesium deficiency. This makes sense, because the runoff on my water is always around 6.2. I've tried watering them with water up to a ph of 7.5, but the run-off is still about 6.2. The plants looked alright until about a week ago, but then the 2 i mentioned earlier started showing the mag deficiency. I foliar feed those two with the recommended dose of epsom salt tonight, so I will post back on how they're doing. Honestly, I was just wondering what I can do to fix the run-off problem. I know the Ocean Forest is ph adjusted, so that might be what's keeping the run-off low. Someone I know recommended I flush them next watering, is that a good idea? Any help is greatly appreciated. Thanks.

[jimnut]

Ok, here's an update. The plant with the worst mag deficiency was taken out and i watered it with about 2 gallons of 9.35 tap water. I checked the run-off on the last cup or two and the ph was down below 6.0. I pulled my meter out, but it was still falling below 5.9 before I took it out and slammed my head against the wall. What is happening here? This makes no sense to me at all from everything I've read on here and in a couple books (a pretty good amount). I literally have no idea what is happening to my plant, and it's taking every once of control in my body to not rip it up and throw it away. God, I'm so confused and angry. Anyways, any type of advice is welcomed. I don't want my plant to die, but it's leaves have been curling the past couple days from the deficiency. Take it easy GC.

[MephistoX]

I just worked on my mag def. I watered w/ 10.0 ph water and went from 5.1-5 runoff to 6.1 in one plant. 5.5 -> 7.0 in the other. I'm going to leave em alone til next watering because I wasn't seeing too much dmg from the low PH and hurt lower leaves.

I used a 3ltr bottle of 10.0 and watered slowly. PH is slow to change in soil, so don't do too much, too quickly.

[Yowler]

I had a mag deficiency in my FFOF too and a pH of around 5.0 in some of the plants. I flushed them all with about 1.5 gallons each, two days later I checked the pH and it was up to around 5.6. I flushed again a week later and now the pH seems to be at a stable 6.5. After I got the pH up to 6.5 I watered them with 1 tsp of epsom salt dissolved per gallon of water.

Just did that today, waiting to see what happens.

[jimnut]

Hey, thanks for the replies guys. That's what I will do too. I will just flush until ph comes up. I guess I was being impatient and wanting instant results, but we all know how that goes. haha

edit: Yowler, let me know if that helped with it.

[Yowler]

Yo, I watered my plants yesterday and the pH was around 6, pretty close to where I want it to be (6.5 ideally). They seem to be back in good shape, tons of new growth coming in and it all looks healthy.

To recap:I stopped fertalizing immediately and flushed the plants with 3 times the container volume of water (1 gallon pot would be 3 gallons of water), I just used tap water because I don't have an RO machine and didn't want to spend 30 bucks flushing the plants.

About a week later I checked the pH and it was still low, around 5.5 so I flushed them again. You want to make sure you don't flush more than once a week and only do it when you would be watering normally (don't overwater). That was a week ago that i flushed the second time, I checked the pH and it was about 6.0 so for the next watering i put 1 tsp of epsom salt per gallon of water and then watered them as usual. Today when I checked them, they seem to be really healthy with tons of new growth coming in.

I'm still somewhat of a noob with this but it seems to be working, checkout cantharis' post on mag defficiency too, real helpful.