Rockwool is a nice clean media which has a perfect Air:Water ratio and comes in a ready to use cube format.
Rockwool is a natural media made from a volcanic rock (basalt). The rock is liquefied under extreme heat in special furnaces and then spun into threads and re-solidified into cube format. The production process guarantees sterility in the final product.
When hydrated, each cube has a consistent 80% Water 20% Air ratio which makes it an ideal media for hydroponics as it is difficult to over water the cubes. This prevents seedling problems such as damping off.
To use this media simply unpack it from the box, fully saturate the cubes and then drain them off, place the cubes onto your propagating table, place the seed in the pre-punched hole provided on top of the cube, shower the cubes with water to wet the seeds and leave the system to irrigate by automated controller. Once the seedlings are at a reasonable size for transplanting simply separate the cubes and place them in the main growing system.
Rockwool is a very popular media in NFT lettuce and herb systems.
Lettuce and herb growers use a single 25x25x40mm cube which is sufficient to sustain the root zone of the plant from the seedling stage until maturity.
A large quantity of cubes can be placed on Ebb and Flow propagating tables without using up much space. The cubes are perfect for NFT systems because they do not release any biofilm or grit which is common for other organic based or free flowing medias. It is therefore very easy to keep an NFT system clean when using rockwool.
The 25x25x40mm cubes have a flat base so they are free standing when placed into an NFT gully. This eliminates the need to use a growpot for support, which saves a grower a lot of time and expense because growpots need to be cleaned and sterilised before reuse.
Rockwool prices are very competitive, and even though the price may be slightly higher than other loose medias, which growers use to manually fill pots, the ready to use cube format of Rockwool saves a lot of time and labour which easily recovers any additional cost. The guaranteed sterility of the media also makes it a wise choice for hydroponics.
Tomato and other vine crop growers (e.g capsicums & cucumbers) typically propagate their seedlings in a 75×75 x 60mm cube on and Ebb and Flow table. Once the seedling has outgrown the cube you simply place it on top of a larger media filled slab, bag or pot and within a day the seedling has anchored itself on top as it expands its root system into the new host media.
Important note – All rockwool cubes must be fully soaked and drained to waste prior to seeding. The cubes will never fully hydrate later on if they are not 100% soaked right through the first time. Full submersion prior to seeding is recommended.
A range of trays are also available from Pure Hydroponics for holding the rockwool cubes when they are in the nursery Ebb and Flow system.
Sizes and Quantities
The Rockwool cube sizes available from Pure Hydroponics are as follows:
- 25x25x40mm Cubes – Slab of 80 Cubes
- 25x25x40mm Cubes – Box of 6000 Cubes (75 x Slabs of 80 Cubes) – 12 Boxes per Pallet
- 75x75x65mm Cubes – Sold Individually
- 75x75x65mm Cubes – Box of 384 Cubes – 12 Boxes per Pallet
- Rockwool Growing Slabs – Various sizes
- Other cube sizes are able to be ordered in if required.
Please contact Pure Hydroponics to discuss which cubes are the best for your situation.