Vermiculite
Vermiculite is a mined mineral rock. There are different types of vermiculite, so make sure you’re getting some that work with hydroponics. Vermiculite as a hydroponic grow medium is very good at retaining moisture, but when used alone it can be too much moisture for healthy roots. its most often used in conjunction with another grow medium like perlite. This gives the roots the moisture it needs while the perlite allows sufficient oxygen to the roots.
Perlite
You may be familiar with perlite as an additive to garden soil. This hydroponic grow medium allows oxygen to get to the roots and better water drainage. It is a type of volcanic glass that, when heated, pop similar to popcorn. Perlite can be used alone in hydroponic systems like the drip system, but it doesn’t retain water very well. It also floats, so it doesn’t work well as a standalone in some hydroponic systems. It is often mixed with other grow medium such as vermiculite; a 50/50 mix works well. Perlite is inexpensive and is also reusable. The dust from perlite is not healthy for you or your plants, so make sure to wear a mask and rinse it before use.
