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  • Large volume 80 Litre bags
  • Grow with rockwool, in pots
  • High air to water ratio
  • Allows fine control over E.C and pH
  • Minimal compaction of substrate
  • Tried and tested hydroponic substrate

Mapito is an often over looked substrate when it comes to growing hydroponically. It is a unique blend of rockwool pieces and polyurethane flakes. The two materials combine to make a highly effective substrate, complementing each other’s physical characteristics and properties perfectly. They result in an ideal environment to build a productive root zone, and offer fine control over conditions such as the E.C and pH of the substrate.

Being easily re-cyclable, it makes for a very cost effective growing media, available in 80 Litre bags.


Mapito is a combination of rockwool and PU flakes. PU standing for Polyurethane. They have two very distinct sets of physical characteristics that when combined at the ideal ratio. Firstly, there is rockwool.

Rockwool is the result of harvesting and processing one of Earth’s most abundant sources, volcanic Basalt rock. The Basalt rock is mixed with chalk and then heated up to 1600 degrees Celsius, where it becomes molten. The molten mix is then spun inside a large spinning chamber, pulling the molten lava into sperate and very fine fibrous strands. Like making candy floss, but with rocks. After it is cooled it is cut into chunks and sent ready to be mixed with the PU flakes.

Despite small traces of residual lime/chalk, for all intents and purposes the process of super heating the basalt rock and spinning into rockwool leaves it an entirely inert substance, both chemically and biologically. Rockwool has a great water holding capacity, and a very low Cation Exchange Capacity, making it ideal for hydroponic practices.

PU flakes (or polyurethane flakes) are a synthetic, plastic based material, refined and made suitable for use as an agricultural substrate. It has a nicely solid structure with unique water holding properties, CEC levels and an Air-filled porosity that makes it the ideal companion for rockwool as a hydroponic substrate greatly reducing the compaction of the substrate. Mapito is the ideal combination of two great substrates.


Compared to other media, Mapito has a good few distinct advantages. It has a great water holding capacity, meaning the plant can get the same amount of water from a much smaller root zone space. Typically, peat mixes have around 15% water holding capacity of their total volume, so in a 10L pot, the plant has roughly 1.5L of water potentially available to play with between each watering. Mapito has a much greater capacity, so a much smaller volume of media is required to achieve the same 1.5 litres available to the roots.

Mapito also has a low Cation Exchange Capacity (CEC). This means that it does not retain nutrients as well as a peat. Compared to peat mixes with a high CEC (that hold nutrients for a long time) mapito easily exchanges nutrients with the nutrient solution every watering, giving much finer control over your E.C and pH.

The PU flakes in mapito, combined with the bite-sized chunks of rockwool, make sure that the although the media has huge reserves of air pockets throughout its structure, it does not compact down and lose its shape over time. Maximum amounts of oxygen are available to your roots at all times.


Mapito is small chunks of Rockwool and PU flakes mixed up at the ideal ratio. It is designed to give all the benefits of growing with rockwool in pots, rather than slabs, and avoid any of the usual associated compaction of the media. Ideal for use in any pot based drip system, or even flood and drain, simply pour out the bag and get going!

Just like with rockwool slabs, before you first plant you need to give them a quick soaking in some pH adjusted water to make sure that the residual chalk/limestone from the rockwool chunks is neutralised, and the pH is stabilised. All this requires is a quick soak in water that has been pH adjusted to roughly 5.0-5.5, for roughly 24 hours. After soaking drain the water away, quickly irrigate the slabs through with a nutrient solution set to the relevant level, for the plants you are transplanting. Usually, an E.C of 1.2-1.4 and a pH of 5.6-5.8 is a good ball park to begin with.

As always, irrigation times very much depend on the entire climate of your room, and how quickly your plants are drinking water. After initially planting out, they may not need watering again for another 3+ days, depending on how long they take to sufficiently root. Soon you will need to increase the frequency of the irrigations and E.C levels as the plants develop. Check runoff levels to keep on top of this. When run off amounts drop, you know you need to increase the length or frequency of irrigations, depending on circumstance.

Each irrigation you should aim for roughly 10% runoff. You can measure this by either volume of the water, or the time of the irrigation. For example, if you drip feed 2L of solution, you want 200ml as runoff. Or if you are irrigating for 3 minutes (180 seconds), you want the runoff to be dripping for 10% of that time, roughly 18 seconds. Checking the E.C and pH of the run-off on each irrigation will indicate how you need to respond with feed levels for your next irrigation

Responding in changes to each irrigation in terms of volume of water and E.C and pH levels is crucial to success in rockwool. Ultimately you are in control of the plant a lot more when growing hydroponically with rockwool. If you are interested in using rockwool for your substrate or want some more advice on getting the most out of your grow, feel free to give us a ring in store. We are happy to help!


Wear long sleeve t-shirts and gloves when handling. The rockwool fibres can be a slight irritant to your skin.

Try to always propagate in smaller rockwool blocks if you are using rockwool slabs as your final growth media. Keeping the same rooting media throughout the plants entire life will make for a much more efficient root system