Product info


CANNA SUBSTRA is the best nutrition for growing on inert substrates such as rock wool. It is used especially on ‘run-to-waste’ systems; these are systems where the drain water is drained off or so called open-hydroponics systems.

  • With CANNA SUBSTRA you can grow with precision
  • There are no damaging ballast substances in SUBSTRA nutrition
  • CANNA SUBSTRA comes in a hard and soft water version.

Product line FAQ

I'm using a re-circulating system. Should I use SUBSTRA or AQUA?

CANNA specially developed CANNA AQUA for recirculating systems. CANNA SUBSTRA should be used when using a run-to-waste system. Please do not mix those two up!

Soak rock wool before use

Never use raw rockwool! The pH is too high. Always soak rockwool before using it for the 1st time. Soak with water or a nutrient mixture with the pH adjusted to 5 and an EC of about 1.3 (ppm values). CANNA Start has been specially developed for this purpose. As well as correcting pH & EC, a pre-soak also ensures an even distribution of the nutrient solution throughout the slab.

Keep your nutrients dark

Light breaks down iron chelates! Because of this, it is very important to ensure that no Ultra Violet light falls on the nutrient solution. Light also causes algae to grow in the nutrient solution, which can lead to blockages. Furthermore, algae can take up nutrient elements and cause nutrient deficiencies to occur.

Keep slabs horizontal

Make sure the rock wool slabs are horizontal. If they are not truly horizontal the moisture will run to one end of the slab. This could mean that some plants become too dry and others too wet.

Amounts of nutrients

Keep a record of the amounts of nutrients and additives you add to each tank of nutrients you mix. You then have a good starting point for the next time!

Measuring EC/ppm

Don’t just measure the EC/ppm of the feed water and the drainage water regularly, remember to measure the EC/ppm of the substrate too.

Substra A and B

You can easily distinguish between CANNA Substra A and B products because the A bottle contents is coloured and the B bottle contents is colourless.

Nutrient tank

Take your time diluting and adjusting your nutrient tank! This is essential for the growth, flowering and development of the plants and will yield the best results.


If you are using CANNA RHIZOTONIC always add this to the feed water before you adjust the pH; CANNA RHIZOTONIC is a natural pH UP product.

Adding acid to water

When you dilute an acidic product, always add the acid to the water, never add water to the acid, if it splashes it will cause burns on your skin or in your eyes!

Mixing nutrients

Measuring the nutrient reservoir works as follows: Take EC/ppm as the starting point, measure it and determine whether it should be higher or lower, based on the values shown in the instructions. Only then should you adjust the pH if necessary. Try to get the nutrient solution’s pH value correct at the first attempt.

CANNAZYM and Clay Pebbles

CANNAZYM extends the life-span of Clay Pebbles and other growing mediums because it breaks down dead roots.

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