Rockwool Guide

Stone wool grow manual

Rockwool, or stone wool, is a type of soilless horticultural grow medium that is used in hydroponic systems in the majority of commercial greenhouses. You can grow an 8ft + cucumber plant in a 4” cube. It is also especially good for growing cannabis plants. Rockwool is finely spun volcanic rock (basalt) that resembles fiberglass insulation. Rockwool is one of the most versatile growing medias. It is literally the ONLY growing media that can dry out to near 0% water content without showing stress on the plants.

Rockwool is a great choice for people who want to save money, be able to dial in your grow exactly how you want it. The only downside is set up take a bit pricier and longer due to having to set up irrigation etc., however the cost per pot per plant goes from $8.00/ 3gal pot (soilless/coco/peat mix), down to roughly 1.40 cents depending on your supplier. And you can grow much larger plants in this, much faster.

– 1 day in hydro = 3 days growth in soil/soilless (vegetative growth only flowering time stays the same)
– More cost effective
– Cleaner
– Efficient
– Looks nice
– Simple and easy
– Limited fertiliser choices as you must go with mostly synthetics as some organics can make it messy and cause issues.
– People claim hydroponically grown cannabis has a different flavor profile
– Mos costly to set up, however it pays for itself with the money you save on soil/soilless media

Getting started
– Take a look around YouTube searching “different rockwool growing methods” and decide which is most efficient for your grow space, we can help with this decision just email us dimensions and a photo/photo of the grow space.
– Once you have decided how you like to use rockwool, weather it be slabs, blocks, or just the rockwool cubes in a dwc setting etc. We are more than happy to help assist you in your decision once you have done some research.
– Once decided we must construct the grow space and get ALL necessary equipment.
– Now all the hard work is done it time for the fun!

“Best” practises of use
Rockwool cubes – clones and seedlings
Equipment needed for this task.
– Humidor dome
– Plug holder for tray
– 1” Rockwool cubes
– Bucket
– water
– Ph meter
– Ph down
– Green up nutrient (or similar product meant for feeding clones and seedlings before they have established roots)
– Spray bottle of 70% isopropyl rubbing alcohol
– Snips (clones only)
– Tweezers (seeds only)
– Gloves
– Rooting gel (clones only)
– Box cutter
– Paper towels
– Variable temp heat Matt

Getting started

– Spray down all tools with rubbing alcohol and wipe with paper towels, put gloves on and spray them with rubbing alcohol, air dry fanning them
– Cut cubes with knife so they don’t rip all messy
– (This step is not followed by all growers, because people are successful both ways but we recommend esp. for newer growers to follow the instructions) fill up bucket with water, ph. 5.5 and dunk until there are no more bubbles. If the rockwool isnt fully soaked the dry spots will create pockets for the salt nutrients to build up and reduce the amount of space in the cubes for root mass to fill it up, so make sure all the bubble stop.
– Place cubes into plug holder
– (seeds) if you have germinated them carefully poke a hole in the cube and stick the tail downwards careful not to snap the tail
– (clones) cut your clone roughly 6” (or 3 nodes at least) on a 45-degree angle dip in rooting gel, and carefully push into rockwool cube making sure you don’t snap the stem holding it close to the cube.
– One tray is full put lid on, place on heat matt. (We have found best results come when the heat matt shuts off at the same time as the lights but this is optional)
– Make sure there is a small amount of water on the tray so the walls of the lid get foggy, check on them daily to make sure there is fog on the walls
– Once seeds show themselves open vents onto of humidor
– After about 7 days open the vents on the clones
– Once roots show out the bottom of the cubes it is time to transplant into your next size cube whichever that may be, a 4”, 6”, or 8”.

( rockwool is inert so there are no nutrients, it is recommended to use a product such as “green up” to pre soak cubes in to help feed clones and seedlings without over feeding them, when soaking the larger cubes it is recommended to use to appropriate fertilizer needed for that stage of growth)

Posted in The Turpene Times.