HollyD
Well-Known Member
My friend Ernie is a new grower and having some trouble understanding pH, PPM, and the proper level of nutrients to use. Unfortunately, he's using nutes that don't seem to be too commonly used: JR Peters' 16-4-17. 1/4 teaspoon of it dissolved into a gallon of water (half the amount listed on the package as giving 100 PPM) was strong enough to burn the dickens out of the plants when they were 22 days from seed. (He thought 3rd full set of leaves was old enough to feed, and that 1/4 strength was safe, he turns out to have been wrong.) Watered only with pH'd water and a pinch of CalNit since then. Plants are now 34 days from seed.
So Ernie got a PPM meter today, and has a pH meter already. But nothing makes sense anymore.
Rain water tested at 0 PPM. pH was over 8.
Adding 1/4 teaspoon of the nutes to a gallon of rainwater shot that down to 4.3 or so and it ended up being 200 PPM instead of the 50 PPM it should have been.
Dumping half of that out and adding the pH'd, slightly CalNit'd water from yesterday to get it to 4.9 resulted in PPM over 300. That's at 1/8 strength based on the packaging for the nutes, with an arbitrary pinch of CalNit since he doesn't actually know how much of that to add. And he hasn't even started adding epsom salts for magnesium.
Reading around, it seems that 300 PPM is fine, but how on earth is he ever going to be able to give these plants more food if this small of a dose knocks the pH down so low?
His guess is to add pH Up or baking soda or something basic to keep it at an appropriate level, but he is a little alarmed by the oddly high PPM already, even before adding other things to the mix.
This is all too complicated for what should be a simple weed. Can anyone spot what Ernie is doing wrong?
Details:
1.5 gallon coco hempy bucket, 70-75% coco coir (rinsed several times with water pH'd to 5.0 or so before planting the rockwool cube), 25-30% coarse perlite fill, 100% perlite reservoir.
Seeds sprouted in pH'd rockwool cube 1/3/15, transplanted to bucket 1/5/15.
One Jack Herer, one Gold Leaf. Plants are small and recently topped but look fairly healthy other than the burned lower leaves from that last feeding.
Growing under LEDs in a grow tent.
help?
So Ernie got a PPM meter today, and has a pH meter already. But nothing makes sense anymore.
Rain water tested at 0 PPM. pH was over 8.
Adding 1/4 teaspoon of the nutes to a gallon of rainwater shot that down to 4.3 or so and it ended up being 200 PPM instead of the 50 PPM it should have been.
Dumping half of that out and adding the pH'd, slightly CalNit'd water from yesterday to get it to 4.9 resulted in PPM over 300. That's at 1/8 strength based on the packaging for the nutes, with an arbitrary pinch of CalNit since he doesn't actually know how much of that to add. And he hasn't even started adding epsom salts for magnesium.
Reading around, it seems that 300 PPM is fine, but how on earth is he ever going to be able to give these plants more food if this small of a dose knocks the pH down so low?
His guess is to add pH Up or baking soda or something basic to keep it at an appropriate level, but he is a little alarmed by the oddly high PPM already, even before adding other things to the mix.
This is all too complicated for what should be a simple weed. Can anyone spot what Ernie is doing wrong?
Details:
1.5 gallon coco hempy bucket, 70-75% coco coir (rinsed several times with water pH'd to 5.0 or so before planting the rockwool cube), 25-30% coarse perlite fill, 100% perlite reservoir.
Seeds sprouted in pH'd rockwool cube 1/3/15, transplanted to bucket 1/5/15.
One Jack Herer, one Gold Leaf. Plants are small and recently topped but look fairly healthy other than the burned lower leaves from that last feeding.
Growing under LEDs in a grow tent.
help?
