Aggregates are mediums used to grow plants in, these provide support for the plants and affect moisture retention and aeration around the roots of the plants. Jiffy-7 are the easiest for propagating seeds and Perlite is the best medium for propagating cuttings.
When using aggregates it can be advisable to elevate your pump from the bottom of the tank to avoid sucking in residue from the aggregate.
Gravel can be mixed with river sand or Perlite to maintain a higher moisture level in the growth medium.
Ensure that the gravel is carefully washed before being introduced into your hydroponic system.
The Jiffy-7 Pellet is made from sphagnum peat from specially selected peat bogs. Lime and a special fertilizer with a low ammonium content are added to the peat in order to stimulate growth. The pellets have a pH of approximately 5.3 and are wrapped in a thin, degradable net.
Simply sit in water and the pellet expands upwards. A small indent is on the top of the pellet, place your seed here once the pellet has absorbed the water.
Perlite is excellent for rooting cuttings and can be mixed with other aggregates to provide ideal medium for use in your homemade hydroponic system.
Rinse the Perlite in fresh water before introducing to your hydroponic system to remove residual dust.
Exfoliated Vermiculite does not retain moisture and generally is mixed with Perlite to form a growing medium.
The Vermiculite in the mixture provides great drainage, while the Perlite will retain moisture and in combination provides a moist aerated environment for plants to grow in.
Rock wool is manufactured by heating rock to 1600ºc and then either spinning it into fine fibres or blowing air through it resulting in fine fibres. Rock wool is good at retaining moisture and can be used without needing to be contained in a pot.
Ensure that Rock Wool does not end up getting sucked into your pump or it will quickly block it.