All your hydroponic growing needs, supplies, advice and more

Nutrients and water control:

To start this section I’ll say that some manufacturers of hydroponic nutrient formulas like to make things very easy.

The good ones really do a good job of it too.

This is another case of how bad do you need to know exactly how each and every part of your plant works.

We’ll look at the basics and then the easiest ways that I know to easily keep your nutrient solution within acceptable levels for optimum plant growth.

Any hydroponic nutrient begins with water.

The water needs to be free of pathogens, with a low EC and a correct PH.

There are meters that read EC but for most applications a TDS meter, or pen works just fine.

These measure Total Dissolved Solids, or salts.

Every once in a while, you will need to calibrate your meter.

This is how you measure the strength of your nutrient solution, or food.

You will need to feed them with a different strength of nutrients depending on which stage of growth the plants are in and knowing how to monitor that makes life a lot simpler.

If you are already a plant expert and know most of the signs of nutrient burn or deficiencies then you may not need these tools.

There are many brands of hydroponic nutrients.

I use GH, so again, these are the products I will use to explain how they work and what they do.


Hydroponic nutrients usually come in either liquid or powder form.


There are organic nutrients and nutrients made from mineral salts.

The main 3 that are called Macro Nutrients and are usually in every fertilizer or nutrient to some degree are NPK.

Nitrogen, Phosphorus and Potassium.

These are used in the largest quantities.

The numbers that you will see on any fertilizer are in the order of Nitrogen Phosphorus and Potassium.

You can expect dry, or powdered fertilizers to be very close to the numbers on the package as they are mostly closely regulated.

Liquid fertilizers can vary wildly, and some have been known to often not have what is advertised at all in the bottle.

I stick to ones that I know, as do most growers. More expensive doesn’t always mean a better product.

In a complete hydroponic food, you should also have Secondary nutrients which are Calcium, Magnesium and Sulfur.

Also, there are micro nutrients which are very important in a hydroponic solution.

Theses are Iron, Copper, Zinc, Manganese, Boron, Molybdenum and Chlorine.



A great additive or element that is commonly used in hydroponics is Silica.

This strengthens stems and leaves. A very important component if you are growing a plant with large weight in flowers.

This strength also helps with pest management as most pests that eat plant material do much more damage to soft, easy to chew plants.


I’ve made my own plant food by following recipes and tweaking them for my own use, but it really isn’t worth the bother when you have companies that devote millions of dollars trying to figure out how to make the perfect food for your hydroponic solution.


We already talked about the 3 main stages of growth.

Rooting or seedling, vegetative and flowering.

During the rooting, seedling and flowering stages, plants can use more Phosphorus than Nitrogen.

During the vegetative stage they thrive with a higher nitrogen solution.

When you see the first number (N) is higher than the rest, that means it is mainly used for vegetative the stage or plants that you don’t even want to flower like lettuce for instance.

When the second number is higher (P) then you know that this is used for the flowering stage.

There is a lot more science to nutrients and fertilizers than this, but again, there is much more than the scope of out time here will allow.

If you want to know more there is a good article on nutrients and additives in the Garden Culture How its Made issue.


Back to PH:

This is another very important factor in hydroponics, or gardening in general.


PH is measured on a scale from 0-14 with 7 being neutral. Below 7 is acidic and above 7 is alkaline.

I use this chart because it shows the difference between hydroponic and soil PH ranges.

As you can see, most elements have specific PH ranges where they will be available for plant nutrition

Thankfully, it is very easily taken care of in water or nutrient solutions.

Tools for measuring Ph levels range from around $10 for a litmus paper or liquid test kit to many hundreds of dollars for lab quality test equipment. 


These pens need to be calibrated occasionally but are a very inexpensive way to keep track of it. I still have the first one that I purchased many years ago.

It was over $100 then and most of them still were until recently.


As I said earlier, it is necessary to have enough oxygen to your plant roots, so the temperature of the solution comes into play here.

The higher the temperature the less dissolved oxygen.

Most plants like a hydroponic solution from about 65 F to 75 F.

Much lower and growth slows.

Higher temperatures, when oxygen gets low is when pathogens can begin to take over the root zone.

Crops don’t have good outcomes when the roots are not happy.

Many people like to think of their plants as babies.

If you give them everything they need to be happy and healthy, they will thrive and resist any disease or pest.