nxsov180db
Well-Known Member
I use hydrobuddy, it's free software you can download to figure out what you're actually feeding. I use it to make my own fertilizer.
What causes this problem in cannabis plants??? (PICS)
- Thread starter ebgms
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Billy the Mountain
Well-Known Member
A bit of simple math
PPM is mg/liter, so:
ppm = Grams/Gal * 264.2 x percentage listed (1000mg/3.785 liters = 264.2)
It gets a little trickier for P and K because the label (in the US at least) lists the oxide, not the elements.
E.g. a 10-10-10 label is actually 10-4.3-8.3 of Nitrogen, Phosphorous, and Potassium
* P is 43.6% of P2O5, K is 83% of K2O
You can do the same for liquids provided you know the specific gravity, usually on the bottle, or simply divide weight by volume.
Yeah I was playing around with this concept earlier and came up with something like the following...
Ok take Jacks Blossom Booster 10-30-20 as an example. I think this means that 10% of the total weight is N, 30% P and 20% K.
Therefore one gram would have 0.1g N, 0.3g P and 0.2g K in each gram.
One gallon of water weighs a fixed number of grams, it's static at 3785.41 grams per gallon.
Thus if we consider grams to be "parts" and one gram of Jacks Blossom Booster 10-30-20 was dissolved in 1gal of water, then
(0.1g of N / 3785.41g of H20) * 1,000,000 =~ 26 parts per million N
(0.3g of P / 3785.41g of H20) * 1,000,000 =~ 79 parts per million P
(0.2g of K / 3785.41g of H20) * 1,000,000 =~ 53 parts per million K
Would that work out or am I missing something?
Kush Inc.
Well-Known Member
Thanks, and FFS start measuring your PH ASAP. Just use a drip set if you don't like PH pens. Those things cost 7 bucks and they work just fine.
Billy the Mountain
Well-Known Member
Close, but you're measuring the oxides (P2O5 and K2O) and not the elements P & K.
You need to multiply P by .436 and K by .83.
Only Nitrogen is given as an actual percentage on nute labels (In the U.S.)
E.g. a 10-10-10 nute is actually 10-4.4.-8.3 as far as elemental N, P, and K
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weedstoner420
Well-Known Member
Man, growing weed with synthetic nutrients can be so complicated. I tried it my first few grows and the results mostly looked like your plants...
Organic soil with dry fertilizer blends is so much easier. Like, you can just take some organic potting soil from the store, add some extra compost (say 20-25% of the total volume), and mix in some Garden-Tone or Gaia 444 or basically any all-purpose organic blend at about 2 cups per cubic foot (7.5 gallons) of soil, and grow some killer weed.
If you use big pots like 15+ gallons, you can likely get away with only giving them plain tap water the entire grow, otherwise you'll probably have to top-dress every 3-4 weeks with the same dry ferts. Easy peasy.
Organic soil with dry fertilizer blends is so much easier. Like, you can just take some organic potting soil from the store, add some extra compost (say 20-25% of the total volume), and mix in some Garden-Tone or Gaia 444 or basically any all-purpose organic blend at about 2 cups per cubic foot (7.5 gallons) of soil, and grow some killer weed.
If you use big pots like 15+ gallons, you can likely get away with only giving them plain tap water the entire grow, otherwise you'll probably have to top-dress every 3-4 weeks with the same dry ferts. Easy peasy.
It depends on what synthetic nutrients you are using. When I was using FF, my plants would be more or less fried by the end of flower. Now I am using GH Flora Nova with much better results and much easier regimen to follow. I like knowing exactly what I am feeding every time I water, instead of wondering if dry amendments will be sufficient. Whatever works for you.