For liquid hydroponics nutes, can the individual N P and K mg/ml be calculated from the NPK ratio? For example, GH Micro has a 5-0-1 NPK ratio. I think that means N is 5% by weight. Searching says there are 1000mg per ml, but I think that means plain water. Is the GH Micro N mg/ml close to 5% of 1000mg/ml? So 50mg of N per ml? K would be 10mg/ml? The reason I ask is that there is a hydroponics study that shows max cannabinoids at different mg/ml of N and P (the study said they apparently used too high of a range of K so couldn't determine optimal values of K, meaning that commercial growers use more K than necessary).
Hi @Rabbitfish welcome to the forums. First, I should point out that different strains and conditions will affect the maximal cannabinoid output and optimal nitrogen values. That's a big reason why numbers are all over the place. There isn't going to be one study for all. Regarding calculators, I would suggest this one for Flora. Breaks it down pretty good, but there is a learning curve. I also use other calculators for alkalinity for well, here take a look: Cool calculators for alkalinity and fertilizers This relates to using {x} acid to neutralize hard water, but it's also something to consider.
Thank you! interesting links but they don't solve the mg per ml issue. I am hoping there is a science/math person here who knows if what I have asked is correct or not - for the NPK ratio of 5-0-1, is there 50mg N per ml? And 10 mg K per ml? If not, how would I calculate the mg per ml of N P or K?
I have no idea why you are trying to calculate the mg per ml. What exactly are you trying to accomplish?
oh sorry, I get sidetracked in my adventures. The 5-0-1 meaning 5% I assume is w/v (weight to volume) measurement where 5% = 5g/100mL. Therefore, in 10mL there would be 0.500g of N. In 1 mL there would be 50mg of N. Similarly, there would be 1g per 100mL of K; 100mg per 10mL and 10mg per mL.
Thank you! I was hoping that was correct. The issue I have is that I wrote a screen to calculate the Total NPK Ratio for all the nutes I am using to compare to 'best' NPK ratios out there (that part works fine), but when I used the above formula, the N mg/ml is higher than the high range that the study said (it said over or under the range resulted in lower cannabinoids). So - I am using too high a level of nutes, expressed in mg/ml (according to that study). In the data table for the Total NPK Ratio calculator I have the mostly GH nutes I use and am adding Canna to see what total NPK Ratio they are using. What are some of the popular brands used here in this community other than GH and Canna? I would like to add other brands in to make my decision on what nutes to use. I am only on my 2nd grow, mostly GH, but may want to upgrade if I see a reason to. Thank you in advance for your help!
I've attached a spreadsheet showing some NPK levels for different schedules. It's sloppy and I am not the author, but it's interesting to look at, and someone like you may benefit. But like I said in the first comment, there is no 'one size fits all'. There are other variables that need to be looked at. I've fed low amounts of Nitrogen to autos and still got nitrogen toxicity, which led me to adjusting the recipes. Good luck with it.
Oh I get it about different approaches, I'm just very new and trying to figure out what to do. I am a tinkerer by nature so I am not content to just use GH, and use according to their directions. LOL Thanks to everyone here for the help.
Many liquid nutrients, like Flora, are three part. They consist of G-row, M-icro, and B-loom components, ie. G-M-B I'm the same way. It takes a while to figure it all out, but it's nice to see others doing it. Cheers bro
I look at them every day, and take photos to compare. But I am not just interested in just not too little or not too much, I plan to experiment and take notes to try to maximize. If I get some leaves that don't look right, I plan to show them to you and ask for help
It's a wonderful hobby, very rewarding and relaxing. Here's a link to one of my journals if you want to take a peek at how I grow. Blueberry Cheese from seed | Grasscity Forums - The #1 Marijuana Community Online
Same thing happens to me with all threads I watch; seems like after a certain period of time I stop getting notifications if I haven't contributed anything new to the thread.
Not gonna lie, people over think waaaayyyy to much. Overloading in P & K never hurts, only colors up the plant, N is where the control comes in. Once N is dialed in by time you hit a healthy veg and match it to the rate the plant wants, the rest is not important. And I never truly measured nutrient... always a scoop here, a dash there, and a sneeze more for Insurance. And if too much, add more water. Truth be told, I always ran high P & K past what the base nutes had, only thing it always lacked was Cal/Mag however they say LED lighting causes that. I ain't no scientist so idk how true that is, however it was always the case in my grows. Finding the tapering off point is the next challenge.