All your hydroponic growing needs, supplies, advice and more

Types of mediums or substrates:

Rockwool, or Stonewool

Rockwool was originally used as insulation, and still is.

You may be familiar with Roxul, sound proofing or fire proofing insulation.

It is made from basically melting rock and silica and spinning it as it cools much like cotton candy.

It has a very high oxygen and moisture retention so works very well for hydroponic crops.

It can be quite forgiving if a pump fails or electricity goes out.

It is easily the most used worldwide for hydroponic  plant production from roses, tulips and cut flowers to 100-acre greenhouses growing food crops.

Because its more forgiving than some substrates it can be easily managed for a beginner.

The most common rockwool for growing you will see are cubes, chunks, blocks or slabs.

 

It has a slightly high pH so depending on the nutrients and water that you use, you may have to adjust the PH more than with other substrates.

 

 

 

 

 

 

 

 

Leca or hydroton, hydrostone etc:

Light Expanded Clay Aggregate

This is made by heating a small piece of clay in a rotary kiln or drum until it pops much like popcorn does.

It’s strong and lightweight so it doesn’t compact around roots.

It’s very porous so it retains and promotes oxygen at the root zone plus it has high capillary, or wick, action.

It’s usually round or irregular but not usually sharp so that roots aren’t harmed by sharp edges.

It doesn’t rot, decay or harbour mold or disease.

It’s chemically inert so its PH neutral and not effected by chemicals and best of all, it can be easily sterilized and reused.

I still have some that I am still reusing from the first bag I ever bought around 1994.

Coco Coir:

Made from coconut husks.

You’ve probably seen these type of baskets made from coco.


This product has been used for many years but is recently gaining popularity and is beginning to replace peat in some places.

I doubt it will ever replace rockwool or leca completely as it is not as sustainable.


Some people use it with peat, soil, rockwool, leca, perlite, a combination of those or just by itself.

It’s an organic substrate so plant roots love it as well as beneficial enzymes and bacteria.

It’s known as a better substrate than peat but more expensive as well.

There are specialized nutrients made especially for coco coir.

It comes loose, or as bricks that expand when watered or as mats, pots etc. much the same as peat is used in different ways.

It also is reusable but only for a few times then it can be composted and used outside.

 

Soiless Mixes:

These are mainly peat based or sometimes coco coir but usually have other added materials like vermiculite or perlite.

There are different grades of peat like fine or course, slow and fast draining etc.

The soilless mix that we use and sell has 22% perlite 78% extra course grade peat so it’s fast draining but still keeps a good moisture content and it has a wetting agent so that it’s doesn’t have to be drowned before water is spread though it evenly.

It has both dolomitic and calcitic lime which buffer the pH and help keep it stable and it also has a starter fertilizer with very important trace elements.