I recently built a DIY hydroponic tower garden and I have a couple of questions on nutrients that I'm hoping someone can help answer. I have been using AeroGarden Liquid Plant Food (at the advice of the DIY guide I followed) in amounts a bit above what is recommended for the 12-pod garden since my tower has 18 pods. I have been measuring my pH, EC, and ppm however and am getting values which are way outside the target ranges I've read about and while some of my plants have been growing really well there are others which are showing signs of yellowing/browning in some areas so I'm concerned.
My system holds 7 gallons of water, which I'm sure is more than the AeroGarden units hold so part of me worries I might be way too diluted and hence the low readings...but I've also read all the warnings above using too much nutrient solution so I'm wary of just adding more. My recent readings are as follows: pH 3.85 (should be 5.7-6.3?), EC 1110 (should be 1,800?), ppm 540 (should be 800?), and I have been adding ~30ml of the solution every two weeks when I top the water off with around 1 gallon.
With that said, can anyone advise on my nutrient situation? Are those measurements as far out of line and as concerning as they look? Is the answer to simply use more nutrients since I have more water in my system, or should I be using different nutrients? Do I need to use pH-up in addition to the nutrient solution I'm using? Any advice on my situation is greatly appreciated!
There are a few things you have to consider when selecting your hydroponic solutions.
1 Nutrient requirements of the plants you are growing. Plants that mature greater than 30 days like tomatoes may have different nutrient requirements at different stages of life.
2. How often you are changing the nutrient solution.
3. volume of of solution.
4. The nutrient value of your sources
KNO3, Magnesium sulfate, Master blend NPK for example
You need to first figure out the nutrient requirements in ppm for your crop. It is easier if you plant the same things in the tower. Without a controller, it is hard to meet the needs of different types of plants. So, they need to have similar needs and mature at around the same time to KISS.
After you figure out the plant needs you have to look at your nutrient sources and calculate the best matches to get your desired ppm for each of the nutrients needed.
The link has the calculations for calculating different fertilizers and the formulas.
It is long, but if you are growing the same thing more or less, you only have to get it right once and then repeat.
I am not used to a topping off method. It is usually mix a basic solution and if the plants are going to be in there longer, then instead of topping off, replace the solution with a new mix.
If you are using a mix for the aeroponics garden, it should be proportiionately increased based on the volume. For example if the aeroponic system used x amount of chemical solution for a 1 gallon tank and you have a 7 gallon reservoir then you need to use 7 times the chemical soilution you used before. Also assuming you are growing similar plants in both systems that will have roughly the same nutrient requirements.
What we are using is a Kratky static hydroponic system. We plant lettuce, bok choy, green onions, basil. Usually only one type of plant, I.e different varieties of lettuce but only lettuce in a single box.
The lettuce blend works for most of the 30 day greens. Our master chemicals are dry so they are weighed or measured. Mixed in separate containers in warm water so they dissolve better. The are added to a 20 gallon reservoir ( the mix below would be increased 20 times) It is important that they not be mixed together and be added to the tank in order or they precipitate out and cause wild fluctuations when the solution is tested. Learned this the hard way when a newbie combined the dry chemicals in one container. We had a hard time getting everything to dissolve. Since the calculations are already figured out for us, we only had to scale it up for the size of the reservoir. Kratky also has a formula for larger plants I.e. tomatoes, but that one does require the solution in the reservoir to be changed. Master Blend is a trade name. If you have something with similar NPK you can use that or you may have to do a recalculation of the amounts to use to get the similar NPK equivalents if the NPK is a lot different. You can source the Mag sulfate almost anywhere from a pharmacy to a garden shop. Calcium Nitrate from an ag supplier in a bulk bag or online. Master blend is also available online or something similar might be available at a hydroponic store.
The most common MasterBlend ratio is as follows:
1 Gallon of Water
2g of MasterBlend 4-18-38
1g Magnesium Sulfate (Epsom Salt)
2g Calcium Nitrate (15.5-0-0)
The nutrients MUST be mixed in a specific order. First, dissolve the MasterBlend into the water. Then, add the magnesium sulfate. Finally, mix in the calcium nitrate. Be sure that each nutrient is fully dissolved before adding the next one.
The recipe can be scaled up or down, depending on the size of your reservoir. When prepping multiple reservoirs, it is always advised to mix the solution in larger batches to promote consistency between your solutions.
https://www.umkc.edu/mide/VeteranFarmer ... 20Care.pdf
https://extension.psu.edu/hydroponics-s ... -equations
https://www.growkratky.com/kratky-hydro ... nts-guide/
1 Nutrient requirements of the plants you are growing. Plants that mature greater than 30 days like tomatoes may have different nutrient requirements at different stages of life.
2. How often you are changing the nutrient solution.
3. volume of of solution.
4. The nutrient value of your sources
KNO3, Magnesium sulfate, Master blend NPK for example
You need to first figure out the nutrient requirements in ppm for your crop. It is easier if you plant the same things in the tower. Without a controller, it is hard to meet the needs of different types of plants. So, they need to have similar needs and mature at around the same time to KISS.
After you figure out the plant needs you have to look at your nutrient sources and calculate the best matches to get your desired ppm for each of the nutrients needed.
The link has the calculations for calculating different fertilizers and the formulas.
It is long, but if you are growing the same thing more or less, you only have to get it right once and then repeat.
I am not used to a topping off method. It is usually mix a basic solution and if the plants are going to be in there longer, then instead of topping off, replace the solution with a new mix.
If you are using a mix for the aeroponics garden, it should be proportiionately increased based on the volume. For example if the aeroponic system used x amount of chemical solution for a 1 gallon tank and you have a 7 gallon reservoir then you need to use 7 times the chemical soilution you used before. Also assuming you are growing similar plants in both systems that will have roughly the same nutrient requirements.
What we are using is a Kratky static hydroponic system. We plant lettuce, bok choy, green onions, basil. Usually only one type of plant, I.e different varieties of lettuce but only lettuce in a single box.
The lettuce blend works for most of the 30 day greens. Our master chemicals are dry so they are weighed or measured. Mixed in separate containers in warm water so they dissolve better. The are added to a 20 gallon reservoir ( the mix below would be increased 20 times) It is important that they not be mixed together and be added to the tank in order or they precipitate out and cause wild fluctuations when the solution is tested. Learned this the hard way when a newbie combined the dry chemicals in one container. We had a hard time getting everything to dissolve. Since the calculations are already figured out for us, we only had to scale it up for the size of the reservoir. Kratky also has a formula for larger plants I.e. tomatoes, but that one does require the solution in the reservoir to be changed. Master Blend is a trade name. If you have something with similar NPK you can use that or you may have to do a recalculation of the amounts to use to get the similar NPK equivalents if the NPK is a lot different. You can source the Mag sulfate almost anywhere from a pharmacy to a garden shop. Calcium Nitrate from an ag supplier in a bulk bag or online. Master blend is also available online or something similar might be available at a hydroponic store.
The most common MasterBlend ratio is as follows:
1 Gallon of Water
2g of MasterBlend 4-18-38
1g Magnesium Sulfate (Epsom Salt)
2g Calcium Nitrate (15.5-0-0)
The nutrients MUST be mixed in a specific order. First, dissolve the MasterBlend into the water. Then, add the magnesium sulfate. Finally, mix in the calcium nitrate. Be sure that each nutrient is fully dissolved before adding the next one.
The recipe can be scaled up or down, depending on the size of your reservoir. When prepping multiple reservoirs, it is always advised to mix the solution in larger batches to promote consistency between your solutions.
https://www.umkc.edu/mide/VeteranFarmer ... 20Care.pdf
https://extension.psu.edu/hydroponics-s ... -equations
https://www.growkratky.com/kratky-hydro ... nts-guide/
Thank you, that was all very helpful. I significantly increased the amount of nutrient solution I'm using after discovering that the AeroGarden 12-pod system is only two gallons while mine is seven. This brought the EC and PPM readings back into the range I'd expect to see, and I used a bit of baking soda to bring up the pH.
I do have different types of veggies in there now so I'm more or less trying to thread the needle for the ideal nutrient range. I suppose I'll see how it goes and consider sticking to a single type at a time for future growing seasons.
I'm sure I'll also look to more affordable nutrient options in the future so I'll definitely hang on to all the calculation resources you shared. Thanks again!
I do have different types of veggies in there now so I'm more or less trying to thread the needle for the ideal nutrient range. I suppose I'll see how it goes and consider sticking to a single type at a time for future growing seasons.
I'm sure I'll also look to more affordable nutrient options in the future so I'll definitely hang on to all the calculation resources you shared. Thanks again!
Hydroponic fertilizer is expensive, but the dry ones are usually cheaper than the liquid ones to purchase and because of the weight of shipping. As hydroponics gains momentum there may be more advantages. Right now, where I am there are only 2 hydroponic stores and 3 ag suppliers. It can be actually cheaper to order things on Amazon than to try to source it locally.