Tall Plastic Pot w/ Grodan® Grow Cubes, 5” Tall, 3.5” Square

Lightweight, injection molded, black plastic pot filled with Grodan® Grow Cubes also known as Rockwool, an inert, lightweight and sterile growing medium. Well known in horticulture for its excellent water retention capabilities and efficient drainage, Rockwool is also a pathogen and pest resistant growing medium. To prepare the growing medium, first poke a few holes into the plastic wrap covering the Grodan® Grow Cubes and through the drain holes in the bottom of the pot, then follow these steps:

Prepare Water: Fill a small bucket or tall container with enough RO, distilled, or deionized water to submerge the pot. *Ideally, the water should be adjusted to pH 5.5 with either 100% pure lemon juice or other organic pH adjuster (pH Down). Pure water is pH neutral (7.0), so add pH adjuster one drop at a time, checking water with a pH tester until desired pH is attained. *If this step proves too cumbersome, soaking and rinsing the cubes several times in pure distilled water will suffice.

Submerge Pot: Next, place entire pot into the water solution, submerging pot completely. You’ll know when the growing medium is fully saturated when the pot no longer floats. Rotate the pot around to remove all bubbles until fully saturated.

Drain Excess Water: Maintaining that the cubes are fully saturated, remove from bucket/container, letting the excess water drain from the pot’s drainage holes.

Prepare Pot: Remove the plastic wrap/tape covering the pot. Displace enough media from the pot to make room for the plant/plug/root ball and you are cleared for transplant!

Optional Check Wet Weight: Note the wet weight of the planted pot of cubes when fully saturated, and let this be your guide for future watering cycles. Even better, if you have a small kitchen scale, weigh the plant in the pot with the cubes fully saturated.

Grower’s Notes: By allowing the Grodan® Grow Cubes to drain freely, over-watering becomes more difficult. The amount of water required between watering cycles is going to depend on the size of your plant, and your own growing conditions: light, temperature, and, especially, humidity, which drives plant transpiration and water uptake. So remember, your irrigation program will depend on your environment and your plant’s needs.

The tray method of watering is just one means of irrigation; overhead watering is another. Just maintain that trays drain or dry completely between watering so that the media maintains a balance of air and moisture. In our experience working with this media, Rockwool/Grodan® Grow Cubes have a similar capillary coefficient to long-fibered Sphagnum moss, that is, the cubes have similar wicking and water retention properties.

Rockwool/Grodan® Grow Cubes is an excellent growing media for Cephalotus and other carnivorous plants. Cephalotus growing in Grodan® Grow Cubes won't get water stressed until the Rockwool is almost completely dry. When in doubt, you can test one of the cubes from just below the surface and squeeze it. Just be aware that this moisture gradient increases towards the bottom of the pot; cubes down below will always be wetter than those up top. And lastly, it’s a good practice to flush the media with pure water (or rainwater) 4X/year to help remove any mineral or organic build-up in the media.