How much substrate should I use per m2?

We recommend a substrate volume of between 7 and 9 litres per square meter of the cropped area of the glasshouse.

This volume is very important because:

1. the more you buy the more it costs;
2. the relationship between the volume of substrate per dripper and the dose size (see how to calculate dose size);
3. the more substrate the more time you have if you have an irrigation issue (safety);
4. the less substrate you have the more controllable it is.

So it is important that the substrate volume you choose matches the capacity of your irrigation system, accuracy of your drippers and your objectives. This is why we developed the Substrate Calculator. Please consult your local Cultilene advisor if you want more information on this.

The volume of a slab can be easily calculated by multiplying its length by the width and the height (in cm) then divide by 1000.

For example a slab = 100 x 20 x 7.5 cm /1000 = 15 litres.

We normally measure the amount of substrate by the number of litres per square metre and this is can be calculated using our Substrate Calculator or manually

For example – Cucumbers

• slab = 15 litres;
• 3 plants / slab = 5 litres / plant;
• planting density of 1.5 plants / m² = 1.5 x 5 = 7.5 litre / m² of substrate.