Hydroponic Nutrient Solution

This page is going to be quite long. This is because I intend on giving a full explanation about hydroponic nutrient solution, what it is, how it works, how you can make your own nutrient solution for hydroponics and I’ll also recommend what i think to be the best hydroponic nutrients available to buy at this moment in time.

So grab a coffee, sit back and relax. At the end of reading this you should have a full understanding about hydroponic nutrient solutions and how to use them to grow some fantastic hydroponic plants.

Water And Hydroponic Nutrient Solution

The purpose of water in hydroponic gardening is to provide a medium to transport all the nutrients which are required for hydroponic plants and to transport them to the roots. For this process to work at its full capabilities, it is very important that the water is of high quality.

Plants take in hydrogen, carbon and oxygen from the air and water. The rest of the nutrients which are needed are taken in from the hydroponic nutrient solution. In order for the roots to be able to easily take in all the many elements from the nutrient solution, then the hydroponic nutrient solution must have the right balance.

This balance changes as an ongoing basis which is why the pH level of your hydroponic nutrient solutions must be checked at regular intervals using a high quality hydroponic pH tester. But more on this later!

Water that comes straight from your tap will often contain above normal levels of calcium, sodium, sulfur, chlorine and alkaline salts. This can mean that the pH level of your starting water can be either too high or too low. For example, if you live near to the coast then there is a high possibility that there will be high levels of sodium in your water supply. If you live in an area with hardly any rainfall then there is an increased likelihood of there being alkaline salts in your water.

In order for your hydroponic plants to remain healthy then it is very important to have high water quality. It is most ideal that the water you use for your hydroponic nutrient solutions contain less than 140 parts per million (PPM) of dissolved solids. Remember that these solids are sodium, magnesium, calcium etc. To check the quality of your water then you will need to use an EC meter. If you do not have an EC meter then your local hydroponic store could test a sample of water for you. However, more on this in a bit.

Once you’ve tested your water and it is below 140 PPM then it is good and ready to mix with your hydroponic fertilizer. However if it is above the safe to use for hydroponics threshold of 300 PPM then i’m afraid you’ll need to invest in a reverse osmosis filter. Reverse osmosis filters will separate your tainted water from your good water, to make it great for your hydroponic nutrient solution.

pH And Hydroponic Nutrient Solutions

The pH scale is a scale from 1 to 14; 1 being most acidic, 7 being neutral and 14 being the most alkaline. For every full point difference in pH, there is a 10-fold increase or decrease in acidity or alkalinity. As you can imagine, a seemingly small change on your pH reading of your hydroponic nutrient solution can have a large effect on your hydroponic plants well-being. Therefore it’s important that you check the pH of your hydroponic nutrient solutions at least every other day using a good quality electronic hydroponic pH tester.

The pH in hydroponic nutrient solution can easily fluctuate by a half point in either direction and not cause any damage to the vast majority of plants. However, larger deviations can effect your plants ability to absorb their nutrients.

So why do you need to check the pH of your nutrient solution so often? Well this is because plant roots take in different nutrients within the nutrient solution at different rates. For example, some plants may take in calcium faster than iron, or others may take in magnesium quicker than potassium. Because of this, the pH of your nutrient solution will drift off in either direction. This will cause the other nutrients not to be absorbed at the usual rate. Depending on what the nutrient deficiency is, the plant may be afflicted with differing ailments.

By making regular checks to pH and by then making the necessary adjustments to your hydroponic nutrient solution by using either pH up or pH down (more on this below), you can easily keep your nutrient solution at the perfect pH level for your plants to thrive. One extra point i shall make on measuring your hydroponic nutrient solution pH level is to take the measurement at the same time every day. This will ensure that the temperature, which can have an effect on readings is roughly the same each time you make the measurement.

Remember also that every hydroponic plant has different optimum pH levels. You need to find out what this level is and ensure you give it to your plant. You will be repaid many times over with healthy plants you can enjoy for a long time.

EC And Hydroponic Nutrient Solutions

As mentioned earlier, we also need to measure the electrical conductivity (EC) of our nutrient solution for hydroponics.

You can measure the concentrations of fertilizer within your water (together making nutrient solutions) by its ability to conduct electricity. Pure water does not conduct electricity, however solids do. The more fertilizer you add to your water, the more it will conduct electrical currents.

Therefore your EC readings will give you an exact idea of the overall strength or concentration of the dissolved solids or fertilizer within your solution. The more fertilizer you add to your water, the higher the EC reading will climb.

Again, as with measuring pH, EC readings are temperature sensitive. So it’s a good idea to take both EC readings and pH at the same time every day. You can get some electrical devices that measure both EC and pH simultaneously, so this will be a time saver. A good quality electrical EC/pH reader can last many years provided you look after it. This includes keeping the metal probes moist.

This next part is very important. Since plants, hydroponic plants in particular use lots of water, you’ll need to be making lots of little adjustments and top ups to your hydroponic nutrient solution. Clearly, as you add fertilizer, up or down solution or water to your existing hydroponic nutrient solutions, your EC readings are going to increase or decrease proportionately. When checking your nutrient solutions EC readings, it’s best to have it between 500 and 2000 PPM. However, the vast majority of plants will thrive best with those numbers narrowed a little more. For the best results, you should be aiming for readings between 800 and 1200 PPM. As you make your daily or thrice weekly adjustments to your hydroponic nutrient solution, your PPM is going to increase or decrease away from these preferred ranges. For this reason and for a few other reasons, it is best to completely change your hydroponics nutrient solution every two weeks.

Changing Your Hydroponic Nutrient Solution

In fact I tell a slight white lie above! Naughty me! Many hydroponic farmers in fact prefer to change their hydroponic nutrient solution every week instead of every two weeks. You’ll need to decide for yourself, taking your EC readings into account if this is necessary for you. Other factors should be how serious a hydroponic grower you are as well as cost. Clearly by changing your hydroponic nutrient solution every week compared to every other week will incur twice the costs on you. If this is a concern to you then a compromise would be to change the nutrient solution every two weeks when the plants are small, then once they grow and start producing plentiful produce, then you can change to every week.

So why else do we need to change hydroponic nutrient solution on a regular basis?

  • To keep your nutrient solution clean and fresh. Isn’t this the kind of drink we all prefer?
  • To prevent toxic salt build up. This will cause numerous problems to your plants.
  • To prevent the growth of algae and fungus.
  • To head off nutrient deficiencies and excesses.
  • To prevent stunted plant growth.
  • To keep pH and EC levels to your plants optimum (as already discussed)
  • It’s generally good practice.

How to change your hydroponic nutrient solution?

The best way of changing your hydroponic nutrient solution is by flushing your entire system with a very mild nutrient solution mix. This mix should be around 25% of your usual strength, maybe a bit less. By doing it this way, you’ll successfully remove far more excess fertilizer than by simply flushing it out with plain water.

You should carry out this flushing of your entire system for around two hours. This means that your pumps should be actively pumping the solution around your entire system for the duration and it should even be feeding the plants.

Mixing Nutrient Solution For Hydroponics

You’ll be mixing the hydroponic nutrient solution in your reservoir, it’s just easier that way. So the first thing you need to do is make sure your reservoir is clean. Using a sponge, wipe away any excess salt build up from your previous solution. Now would also be the best time to ensure everything, your pump mostly is in good working order. If you’re using an aeroponics system then give extra care around the spray nozzle to ensure there’s no salts or debris clogging it up.

Fill up your reservoir with pure water. Make sure you’ve already checked the EC readings of your input water (see above), if it’s higher than 300 PPM solids then you’ll need to use a reverse osmosis filter to remove them.

Depending on the individual fertilizer you’re using and the volume of water in your reservoir, you’ll need to determine the volume of fertilizer or fertilizers to add to the water. The fertilizer should come with some instructions to help you determine the correct amount to add. If you’re still in any doubts then simply contact your local hydroponic dealer who should be able to give you some advice.

Your liquid fertilizers can of course simply be added straight to the water in your reservoir. However, on the rare occasion you may be using solids or powders then a good idea would be to dissolve them in a glass of warm to hot water before adding them to the mix. Ensure the powders are totally dissolved before adding them in.

Once everything is added together then give it all a good mix. Return to the mix one hour later and take your pH and EC readings. If your pH is too low then simply add pH up and obviously if it’s too high then add in some pH down until you reach the desired level for whatever you’re growing. That’s all you need to do.

Remember to check daily or at least every other day and make the necessary amendments to the hydroponic nutrient solution.

Hydroponic Fertilizers

It’s the hydroponic fertilizers that you add to your water to make hydroponic nutrient solutions!

The very best hydroponic fertilizers are the ones that are soluble and contain all the necessary nutrients for your plants. They should also not leave behind any impure residues as this will cause extra work for you when it comes to changing the solution. The best hydroponic fertilizers are manufactured using food-grade nutrients in the formula.

You can buy your hydroponic fertilizers in either one or two-part formulations. Many hydroponic gardeners prefer the simplicity of a one-part formula, as all you need to do is add it to the water therefore they are more simple to use. The two-part formulations tend to separate the macronutrients from the micronutrients. The advantage of the two-part formulations is that you have that little bit more control over what you’re adding to the mix. Depending on what you’re growing, this could be an advantage.

If you’re in any doubt as to the best type of fertilizer to use then the best thing to do is to consult with your local hydroponic store, otherwise simply look online for the answers. This very site is a good place to start regarding optimum levels of pH for what you’re growing.

Adjusting Hydroponic Nutrient Solution – pH Up Or pH Down

Since I’ve already touched on this, I’ll be very brief to finish this article. You need to check the pH of your hydroponic nutrient solution at least every other day.

If your hydroponic nutrient solution has drifted downwards, then you’ll need to add pH up. pH up is usually potassium hydroxide. Likewise if it’s drifted upwards then you’ll need to add pH down, which is either nitric acid or phosphoric acid. Always make sure you give the mixture a good stir after adding either up or down, leave an hour and then check the pH level once again to ensure it’s within the desired range.

You may have read in a couple of places that you can use vinegar to act as pH down or baking soda to act as pH up. This is not a good idea as this can cause algae and fungus growth. You may also end up with hard to clean residues when you do your weekly or fortnightly clean. In addition, while citric acid to act as down may kill one type of bad bacteria, you’ll be trading it in for another type of bad bacteria which thrives on the stuff. Although some people may disagree, my advice would be to play it safe and to stick with the commercial mixes you can buy online or at your local hydroponics store.

If you’ve enjoyed this article, or have any further questions or comments about hydroponic nutrient solution then please leave a message below!

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