[Grodan](https://www.grodan.com/global/solutions/stonewool-growing-media/) rockwool mini cubes. [Product page](https://firstrays.com/product/grodan-mini-cubes/) from First Rays LLC. Rockwool mini cubes might seem like an ideal medium for Nepenthes: - they absorb & retain a lot of water. - they allow for lots of oxygenation due to the spaces between the cubes. - they are inorganic, so not subject to any significant breakdown over the longterm. However, the particular chemistry of rockwool does not interact well with the roots of all Nepenthes. All my clipeata hybrids did poorly in this medium, and some died. For complex hybrids, half-siblings from very similar crosses responded differently -- some grew well, while others struggled. The plants that adapted best were N. x splendiana and N. x rokko 'Exotica' -- see photos below. Note from 2026: Instagram user [zawmbiecarnivores](https://www.instagram.com/zawmbiecarnivores/) ([[Bill Brandyberry Jr]]) noted that he grows all of his larger Nepenthes in a mix of rockwool cubes and pumice. #### 2015-08-16 [[Nepenthes x splendiana|N. x splendiana]] growing in 100% Grodan rockwool mini cubes in this photo. 1 gal. US nursery pot. <a data-flickr-embed="true" href="https://www.flickr.com/photos/60359429@N08/20624831732/in/album-72157647417495448" title="Nepenthes splendiana"><img src="https://live.staticflickr.com/734/20624831732_04b93f13e9_w.jpg" width="360" height="640" alt="Nepenthes splendiana"/></a> #### 2026-09-17 [[Nepenthes x rokko Exotica|N. x rokko 'Exotica']] growing in 100% Grodan rockwool mini cubes. Of all the plants trialed in rockwool cubes, this plant did the best. It was still growing vigorously at the time this photo was taken; there were no signs of stress from being "rootbound". Note the large tap roots, probably from the _thorelii_-aggregate heritage. <a data-flickr-embed="true" href="https://www.flickr.com/photos/60359429@N08/29325389403/in/album-72157656458775853" title="Nepenthes Rokko Exotica"><img src="https://live.staticflickr.com/8201/29325389403_3dbb0c7252_z.jpg" width="575" height="1024" alt="Nepenthes Rokko Exotica"/></a> <a data-flickr-embed="true" href="https://www.flickr.com/photos/60359429@N08/29951534985/in/album-72157656458775853/" title="Nepenthes Rokko Exotica"><img src="https://live.staticflickr.com/8559/29951534985_749dff81b0_z.jpg" width="575" height="1024" alt="Nepenthes Rokko Exotica"/></a> [[Nepenthes in inorganic media]] | [[Nepenthes cultivation]]