Hydroponics Forums Discussions

Hydroponics Forums Discussions (http://www.hydroponicsonline.com/forums/index.php)
-   Hydroponic Nutrients and Mediums (http://www.hydroponicsonline.com/forums/forumdisplay.php?f=4)
-   -   Potasium Nitrate (http://www.hydroponicsonline.com/forums/showthread.php?t=3340)

Jack Schmidling 01-10-2017 02:09 AM

Potasium Nitrate
I am interested in experimenting with home made nutrients and was delighted to learn that KNO3 is a highly regarded source of N because I happen to have a 5 lb bottle left over from another life.

Problem is that if I use enough KNO3 to get the N I want, the K goes out of the ball park.

Is there a way to remove the excess K? I don't understand how it can be used as a source of N if this is always the case.

I also have a bottle of Nitric acid and was wondering if I can use this directly as part of the N and use the KNO3 as the K source.


Marengo, Illinois

GpsFrontier 01-10-2017 04:05 AM

Hello Jack,
I see you've discovered the problem with making your own nutrients. Unless your a chemist and know what your doing, you have to fallow a recipe exactly, you can't just substitute raw mineral salts without throwing off the balance of nutrients. There was a time when I wanted to make my own nutrients as well. Mainly because I wanted to grow a lot more plants and saw that for the amount I would be going through, the cost for nutrients was going to get very expensive.

But then I found out that the nutrients are actually very cheap and realized there are manufactures that sell very cost effective nutrients. The high priced nutrients are simply just way overpriced and all marketing. Now I don't bother wasting all that time trying to learn chemistry and doing trial and error trying to develop nutrient recipes. I leave that up to the chemists, who work for the nutrient manufactures. Even if I did spend all my time going through learning chemistry and doing the trial and error, as well as buying all the separate raw mineral salts and equipment. I still wouldn't be able to make my own nutrients any cheaper than I can buy them already made for. So I simply don't see any point in bothering.

But if you still want to try making your own nutrients, and if you haven't already, I strongly recommend you get some experience growing some hydroponic plants successfully with commercially manufactured nutrients first. There's going to be enough of a learning curve just growing hydroponically to start with, without trying to throw in the complexity of making your own nutrients as well.

If you going to try and make your own nutrients I hope you have a background in chemistry. Before you do here is a website that you should study Science in Hydroponics, it was written by a chemist who has a interest in hydroponics. He's even developed a software program he calls the hydro buddy to help you alter nutrient recipes and keep the balance of nutrients.

Jack Schmidling 01-10-2017 11:31 AM

Thanks for the words of wisdom.

For background, I have decades (6?) of serious soil gardening and about 3 weeks of floundering around with hydroponics. My oldest "crop" is 2 radishes about one inch tall.

My usual MO is to avoid commercial products whenever possible. It's not just the money, it's more of a life style.

I have experiments using everything from distilled water to a soup starting with 19-19-19 and every diy suggestion I could find.

None of them look much better than the plain tap (well) water and most have been scrapped.

I have been pouring over the Scienceinhydroponics web site for the last few days and have learned a lot.

I will take your advice and get a known working nutrient as a control instead of stuff predicted not to work as a control.

Having said that, I am trying to use Hydrobuddy to come up with a mix that will simply provide the NPK that I need so I can then play with the other variables.

By using Potassium Nitrate, Nitric Acid and Ammonium Dibasic Phosphate, I can juggle around to get what I want.

I have two questions on this mix:

1. I have a bag of Triple Super Phospohate and I am having trouble fitting this into his list of substances and the closest I can get is Ammonium Dibasic Phosphate. Is this reasonable or is there a better choice?

2. I need to come up with 8.3 g of Nitric acid and need to know how to convert that to ml or grams of 30% acid.

Any help here? I am clearly not a chemist.



Jack Schmidling 01-10-2017 12:20 PM

Picking a nutrient, even from your list is a bit daunting.

My immediate needs are for radishes and/or lettuce in a wick type static system.

I came up with this...


would this be appropriate or can you point me to a beginner level nute.


GpsFrontier 01-11-2017 12:32 AM

Hello Jack,
Having 6 decades of growing plants is certainly a plus, however growing plants hydroponically is much different than growing them in soil. I'm sure your familiar with what healthy plants look like, identifying pest and fungal problems. You may even have experience identifying nutrient deficiency and toxicity, but you still have a big learning curve coming growing hydroponically, and much of it you learn by doing and experiencing. Three weeks and 2 radish plants isn't much experience growing hydroponically at all.

I'm not trying to scare you or minimize your experience and what you've accomplished in the past. I'm just trying to help you understand the reality that there's a difference and always a learning curve. I've seen so many people feel so confidant that they know all about growing hydroponically because either they are used to growing plants in soil or read a lot about growing hydroponically. Then they go all out taking on more than they should have and run into many problems they never saw coming, and ultimately fail. Wasting a lot of time and money along the way. So I try and help people make those mistakes if I can.


My usual MO is to avoid commercial products whenever possible. It's not just the money, it's more of a life style
Well that's not exactly true in this case. I'm not saying your lying. But if you think about it your not avoiding using commercial products making your own nutrients. Did you make the Potasium Nitrate yourself? Did you go foraging for it in the woods? No, it's a manufactured product. When you make your own nutrients your using manufactured products. Your just combining different manufactured products together to make your own product. That's no different than what manufactures do. The only difference is your not selling what you make and they are.

Unfortunately I can't help answer chemistry questions. As I said, I'm not a chemist, and have no interest in becoming one. Not since I realized there wasn't any point or need in going to the trouble. Would doing so save me money? No. Am I trying to grow produce that will win a blue ribbon at the state fair? No, I'm just want to grow happy healthy plants. If I were a commercial grower I would want a nutrient designed specifically for the plants I'm growing. However there still wouldn't be any benefit in making my own nutrients. If I wanted a custom made nutrient, I would talk to a company that custom makes nutrient for commercial growers. Not only do they have the experience ad equipment to not only develop the recipe and test the plants, but they can still make the nutrients cheaper than I would be able to. They will even test my water supply and adjust the recipe to what's already in my water supply.

However if it was me and I were trying to make my own nutrients and trying to get some answers to chemistry questions. I would first try and contact the owner of the "Science in Hydroponics" blog. He is a chemist and would be the best person to ask. I think there is a e-mail address somewhere on their website to contact them with. If not, I would probably try contacting manufactures that custom make nutrients for commercial growers. Their likely to want to make them for you, but you do need to buy a minimum quantity. However they may still be willing to help you if they feel you will be buying the raw mineral salts you need from them.


Picking a nutrient, even from your list is a bit daunting.
The general hydroponics Flora Nova nutrients are fine and theirs nothing wrong with them except their expensive. Their great for new growers getting started. In fact I used the three part Flora series nutrients myself when I first started. However as you continue growing and start growing more and more plants it gets expensive. When breaking it down it can cost 30 cents or more per gallon of nutrient solution. In other words would cost $3.00 or more every time you change the nutrients in a 10 gallon reservoir (30 cents x 10 gallons= $3.00). So it's fine for starting out, but once you start growing more and more, you'll want a more economical option.

As an example the 1 pint bottle of Flora Nova nutrients you provided the link to cost $14. According to the manufactures mixing directions it takes 7.5 mL per gallon for full strength nutrient solution. One fluid oz is 30 mL. So doing the math the one pint bottle of flora nova will make 64 gallons, and cost 23 cents per gallon. Wich is a little better than the Flora series I used, but still way to high to be considered economical or cost effective.

7.5 ml x 4= 30 ml
One fluid Oz makes 4 gallons of full strength nutrient solution.

4 x 16= 64
So the one pint bottle of Flora Nova makes 64 gallons of full strength nutrient solution.

$14 divided by 64= $0.23
That costs 23 cents per gallon of nutrient solution, and that doesn't even include shipping costs. That bottle could easily cost $8-$10 to ship. raising your cost to 34 cents to 37 cents per gallon of full strength nutrient solution. That's probably OK if your just doing a small grow, but if you plan to grow much your going to need a more cost effective option. I don't consider nutrients to be cost effective unless their about 10 cents per gallon or less. In fact I prefer them to be under 5 cents per gallon. The Verti Gro nutrients and JRpeters are the two most cost effective I've found so far, and if you buy them in the larger quantities cost about 3 cents or less per gallon of full strength nutrient solution.

Can I make my own nutrients for under 3 cents (and that includes shipping costs) per gallon of full strength nutrient solution? No, so why waste my time, money, and effort trying. It just doesn't make any sense to me.

For the radishes and lettuce I would just use verti gro's standard F combo, it's a good general all purpose nutrient. It comes out to about 9 cents per gallon of full strength nutrient solution, but the costs go down the bigger the quantity you get. If you get the 25' lb quantity it's only about 3 cents per gallon of nutrient solution. JR peters nutrients are very similar in price. Though you may want to contact them to ask which product they recommend for the particular plants you want to grow. You'll also probably have to ask them for mixing directions. They sell mostly to commercial growers that use a injector system in non recirculating hydroponic systems. But if you ask them they will tell you haw much to use per 100 gallons of full strength nutrient solution, from there you can just do a little math for smaller water volumes.

Jack Schmidling 01-11-2017 11:01 AM

You seem to have misread just about everything I said so I won't try to sort it out.

However, the link I sent to you was based on the inclusion of General Hydroponics as a source of "cost effective nutrients" as opposed to "high priced nutrients are simply just way overpriced".

It looked like the overpriced stuff to me but I assumed you meant what you said and ordered some.

I would suggest that you make a specific recommendation to get beginners going.


GpsFrontier 01-11-2017 07:24 PM

Hello Jack,
The link to the General Hydroponics nutrients in the "cost effective nutrients list" is specif to the "Maxi Gro" series of nutrients. It's even says so in the link. I never said anything about the flora nova product and have never used it either. I do understand it's thick like syrup though.

Just because there is a link to one General Hydroponics nutrient doesn't mean that everything general hydroponics sells is "Cost Effective." That's why I mentioned the maxi series nutrients specifically, and the link is to the exact product. While on the higher end of the spectrum, when broken down the maxi series nutrients generally cost between 10 and 15 cents per gallon of full strength nutrient solution. They don't state exactly how much the 2.2 lb package makes, but I have measured it out and done the math to find out. I have the numbers written down somewhere, but don't remember off the top of my head exactly. If your really interested in them I'll look for the numbers sheet so I can tell you correctly.

As for specific recommendations, I can't give specific recommendations that fit every situation. Plants are different, that's why nutrient manufactures make different formulas. I can only give specific recommendations when I have specific information about the type of plants your growing and your goals. I did just that when you gave me the the specifics of the plants your growing and asked for a recommendation. I don't understand what you mean by "beginner level" because every nutrient can be used by beginners. As long as you can mix water and do a little rudimentary math to calculate the amount you need to use for the specific water volume of your reservoir, all nutrients are beginner level.

The point of the cost effective nutrient list isn't to recommend one specific product. It's to provide options. Options that are cost effective. Not every nutrient manufacture has the exact same price scale. Their all different. If I narrowed the list to just manufactures that had nutrients that cost under 5 cents per gallon there would be only two options on the list and you would have to buy 25 lb quantities. That doesn't mean there are only two that exist, just that I know of right now. Many people don't want to buy that much, especially when their just getting started, and have never used those nutrients before. That's one reason there are other options on the list.

The second reason is many people don't want to order products online. They may not want to pay for shipping. Or they may be out of nutrients and need them right away and can't wait a week or two for it to arrive. So they want options they may be able to find in their local hydroponics shop too.

The third reason is because manufactures change. They change their product lines, they change their pricing, they sometimes even discontinue products or go out of business. If I narrowed the list to just one or two options, and they discontinued those particular products or go out of business, then there are no options at all.

The whole point of the cost effective nutrients list is to provide as many cost effective options as I can. In order to be considered cost effective I have to have a cut off point. That cut off point is 15 cents per gallon of full strength nutrient solution. Even that isn't exact because not all retailers sell the products for the same exact price. So I have to look around to see what the average cost is for the product. Some like verti gro don't sell their products through retailers, they sell it direct, and some may sell direct as well as on their own website. If they sell direct and/or on their own websites I use their websites pricing. But others like General Hydroponics don't sell direct, they sell through retailers, so those I have to look around to find out what retailers are selling it for and average it. So the cost per gallon may vary depending on where you get it from and if you have to pay for shipping.

It's no doubt that there are nutrients that are more cost effective than others, but it's up to you to decide what fits your situation and needs the best. If someone wants specific recommendations their welcomed to contact me and let me know what their growing as well as their situation, and I'll be happy to make recommendations. But I can only give specific recommendations on specific information.

All times are GMT -4. The time now is 02:38 AM.

Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2021, vBulletin Solutions, Inc.