My plants are consuming fertilizer faster than I can put it on! (according to PH meter)

Susanne

Susanne

Well-Known Member
I've been using Fox Farm Grow Big 6-4-4 for my plants. I noticed some looked Nitrogen deficient, so I bought a ph meter just to check......well, now, I'm finding even after fertilizing the ph is still 6.5. .. the next day, most are reading 7.0. I'm using 3 tsp per gallon (it says 2-3). The plants are in 15-20 gallon pots (outside), and I use approximately 2 gallons each (until it starts running out the bottom). Last week since the meter was reading 7.0 so fast, I ended up fertilizing Sun, Wed AND Sat! And, by Monday, they all read 7.0 again. It has rained a little, but not that much lately, and the plants have been staying fairly wet, but not wet enough for the rain to have leached out the fertilizer. BTW, no more yellow, spotting, falling off leaves (not many, anyway) .
My question is: is this right? I've been buying more fertilizer, and am about to purchase even more (I only have 9 plants). Two weeks ago, I bought a quart, and I'm going to buy a gallon now, if this is the way it's supposed to go, since I'll have to use this formula for awhile, especially on the Afghan, which won't flower as soon. They're just showing signs (one is) of blooming. The AK47 have started to show signs of blooms more so, but it will be awhile before I change to the blooming fertilizer. that will be my next question...another thread so i don't mix it up ;).
So, before I make the order, should I be fertilizing this much?
thanks!
 
greg nr

greg nr

Well-Known Member
Uhhhm, you do know a Ph meter reads Ph, not ppm, right?

Ph really doesn't have anything to do with the amount of nutrients you are adding to your soil. Nutrients can alter the Ph, but that is because of what's in them more than than the concentration.

To measure concentration, you need a ppm or ec meter.

If you are growing outside in the ground, there isn't much you can do about the Ph of the soil anyway. But you can still burn your plants with too much food......
 
Susanne

Susanne

Well-Known Member
They're in 15-20 gallon pots. I'm just learning about the Ph meters and what they read. I read the threads all day a few weeks ago trying to find what to buy and what they tell you. I think I did better two yeas ago when I planted 'johnny appleseed' seeds (a handful given by a friend who had some a friend gave him....they were all different ;0 ).... and HEALTHY. I didn't do as much research or go through as much trouble. This year, due to pain and nausea, etc... from illness, I ordered seeds specially made for my needs, so I'm more concerned with how they do. Unfortunately, we only have a small patch in the woods for the nine plants (1 died at birth :( ), and there isn't enough sunlight, so they aren't as bushy as I'd like, but when we planted two years ago, the "weeds" we grew, did pretty well. One was NINE feet high! We had a LOT of rain in May, which made them all shoot up.....
So, I guess it's back to the books for learning about the Ph.
 
Susanne

Susanne

Well-Known Member
Dr.Nick Riviera said:
how does checking ph tell you it's nitrogen deficient?
Click to expand...
It's not the ph that told me it was nitrogen deficient. I went by the look of the leaves. I checked thread after thread and looked at zillions (it seemed that way!) of photos and determined that was the cause of the yellowing, spotting and dropping of leaves. When I got my meter, the one that lost the most (and, it was really more than the others) turned out to have a higher Ph, and won't stay down. I think it's because the soil in it is looser than the others, and the water/fertilizer runs through it too fast. It also shows "dry" on the meter when the others are normal. ..? I'm still learning. I also don't think my meter is really good at the wet/dry reading. It reads dry when I can tell it's moist. It sticks to my hands, it's so moist....? I knew more before I got the meter!
 
greg nr

greg nr

Well-Known Member
Ph is a measurement of the acidity or alkalinity of a liquid. What are you measuring? Soil or the nutes you are adding or runoff?

You should probably stop feeding until you see what is going to happen over the next week. Depending on the size of your plants, you want to feed them somewhere in the region of 800-1500 ppm once a week.

Grow big will add ~ 75 ppm/ml/gallon. 1 tsp is about 5ml. So for 3 tsp you are adding about 1125 ppm per gallon. Not bad unless you are feeding every day. :(
 
greg nr

greg nr

Well-Known Member
Susanne said:
It's not the ph that told me it was nitrogen deficient. I went by the look of the leaves. I checked thread after thread and looked at zillions (it seemed that way!) of photos and determined that was the cause of the yellowing, spotting and dropping of leaves. When I got my meter, the one that lost the most (and, it was really more than the others) turned out to have a higher Ph, and won't stay down. I think it's because the soil in it is looser than the others, and the water/fertilizer runs through it too fast. It also shows "dry" on the meter when the others are normal. ..? I'm still learning. I also don't think my meter is really good at the wet/dry reading. It reads dry when I can tell it's moist. It sticks to my hands, it's so moist....? I knew more before I got the meter!
Click to expand...
What kind of meter is it? Is it one of those $7 combo moisture meter/Ph meter deals? I wouldn't trust those for Ph..... Just saying.
 
Susanne

Susanne

Well-Known Member
nah, not $7 one, but a $18 one ;). I looked & looked; read the threads & so many different opinions. I don't trust it either....also just sayin' ;). My plants did just fine a couple of years ago without a meter. The only ones that were totally trusted cost more than I am willing to spend. I think I'll trust my eyes and looking at the plants.

Oh, and I'm measuring in the soil, not the runoff. The probe is about 9". The plants are about 3-4' tall right now. They're a little 'tall' for their size, as they haven't gotten enough sun where they are. We don't have a better place to plant them. We planted there two years ago, and it's grown up around it. I think we may try to do some discrete clearing around it a little to get more sunlight for next time.
 
Susanne

Susanne

Well-Known Member
Chemphlegm, sounds like what I was wanting to hear anyway. It seemed over the top to me. I'll check on that. thanks.
 
D

Dr.Nick Riviera

Well-Known Member
Susanne said:
Chemphlegm, sounds like what I was wanting to hear anyway. It seemed over the top to me. I'll check on that. thanks.
Click to expand...
yeah, forget that meter and it's readings. you mix the nutrients(fertilizer) and measure their amount in the parts per million or PPM, you then test and adjust the ph to 5.8 and then water your plants. if you are using a store bought soil, it probably has ph buffers so the soil ph is always in the zone.
 
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