These instructions represent a combination of Grodan’s information, my personal views and feedback from customers on rooting cuttings in rockwool.

The growing area must be completely sterile. All tools, benches, etc. can be disinfected with 1 part household bleach 9 parts water solution.

For the cutting kit, prepare a one-third strength nutrient solution using a complete fertilizer such as our liquid David’s Grow. This solution in then adjusted to a pH of 5.5 to 5.7 using phosphoric acid is the pH down. Use this solution to soak the number of starter cubes or plugs needed for the cuttings to be taken. Place the compartmentalized tray into the flat with holes. Space the cubes in a staggered arrangement in the compartmentalized tray. Next, place the flat with the starter cubes into the flat without holes. Take cuttings from clean disease-free stock. Cut off the leaves from the base of the cutting so that you have a at least 1 node free of vegetation. Large leaves on the upper part of the cutting can be trimmed to smaller size if necessary. Dip’N Grow can be used as the initial root-Inducing substance. The concentration for Dip’N Grow for softwood cuttings is 1 part Dip’N Grow with 20 parts of water, Though some customers use a more concentrated solution. Hardwood cuttings can be dipped in a 1 part Dip’N Grow, 5 parts water solution. Dip the cutting stem into the Dip’N Grow mix for a few seconds. Gently insert the cutting about 1 inch into the cube. It is essential that there is good contact between the cuttings and the rockwool so that the base of the cutting is able to exchange oxygen and carbon dioxide sufficiently. Lack of oxygen and carbon dioxide exchange and poor water uptake will adversely affect the formation of roots. Cover with clear dome. At least once daily remove the dome and mist the cuttings with lukewarm water. Watering the cubes should not be necessary until roots have formed. If it does become necessary, water the cubes with one-third strength nutrient solution and allow the cubes to drain. Recent studies have shown that cuttings benefit from more light intensity than previously thought. If you are using fluorescent, such as our G.E. full spectrum bulbs, keep the bulbs 3 inches above the propagation dome. Begin checking for rooting 1 week after the cuttings have been taken. This can be accomplished by giving the cutting’s stem a gentle tug. If there is resistance from within the cube, this indicates rooting has occurred once the cuttings have rooted and start actively growing remove the dome and give them more light.

If you have the Aeration Kit place the bubble wand between the flat with holes and the flat without holes. Cut a hole in the top tray, and dome to run the air hose through. If you place your air pump above the height of the flats, there is no need to use the check valve. If you must have the air pump below the level of the trays, use the check valve. The fertilizer solution for the Cutting Kit with Aeration kit is the same as for the Cutting Kit but with 1/4 teaspoon of Dip’N Grow added. Soak the cubes in this solution and place the cubes in the compartmentalized tray. Add one gallon of the solution to the trays, so that the bottom 1/2 inch of the cube is immersed in solution. The air pump can be run continuously, as this will provide fresh oxygen and CO2, as well as keeping the humidity high. Proceed with the same steps as for the standard cutting kit. Using the Dip’N Grow step is optional.

Grodan recommends watering with nutrient solution when the rockwool reaches 60% of its saturated weight. An easy Way for the hobbyist to check the need for watering is to squeeze the cubes very lightly. If no water drips out of the cubes, it's time to water with the full-strength nutrient solution. Of the day's total watering, 20 to 30% of the solution should come out the bottom of the block and be disposed of.

When 4 to 7 healthy white roots have penetrated the base of the cubes, they are ready for transplanting into a larger plastic wrapped growing blocks. The cubes should be soaked in a full-strength, pH-adjusted nutrient solution such as Formula One. The blocks, prior to use, should be thoroughly soaked in nutrient solution. Place the small cube inside the hole in the larger block. To discourage the growth of algae, cut a 3” square piece of white plastic with a slit for the stem and place on top of the block. The plastic should not touch the stem. When the plant is large enough to completely shade the rockwool, the plastic can be removed.

When roots have penetrated the blocks, it's time to place the blocks on the plastic wrapped slabs. Space the slabs to achieve your desired plant density. This plant density will vary depending on varieties and techniques used. There is a top and bottom to every slab. On slabs with a seam running down the length, there is a small puncture hole accompanying the seam, which is always facing up. To prepare the slab for growth, cut a flap in the plastic where each plant is to be placed. The flap should be large enough so that when it is folded back, there is enough room top your growing block to make full contact with the rockwool of the slab. Fill the slab with the nutrient solution until the plastic sleeve of the slab bulges with excess solution. Allow the slab to soak for up to 24 hours. Alter soaking, the slabs should slope 2 degrees towards the drainage area. Cut a 2" drainage slit at the base of the slab at the end closest to your trays drainage hole. slits can also be made along the length of the slab base, if desired. Place the growing blocks in the cut flaps on top of the slab. If using drip emitters, keep then on top of the blocks, making sure that the dripping solution does not touch the plant's stem.

With automatically-timed waterings of rockwool, it is advisable to do your first light watering one hour before sun up to charge the slab. Water frequently until the plant’s roots have established themselves from the block securely into the slab. Once the plants have secured themselves to the slab, you can begin watering when the slabs dry to 60% of their saturated weight. Hand watering also gives good results with only one watering a day; just be sure that the slab is large enough so that it doesn't go below 60% saturated weight between waterings. We suggest flushing the slabs with 100% excess nutrient solution at least once every 2 weeks.

THE 4 MAJOR RULES OF WATERING ROCKWOOL ARE:

1. Always maintain a pH of approximately 5.8 in the nutrient solution.
2. Maintain a full-strength nutrient solution during every watering.
3. About 20 to 30% of the total solution applied during any given day should leach out the bottom of the rockwool. Flush 100°,of the nutrients every 2 weeks.
4. Never drench rockwool with a fungicide or insecticide at 100% of recommended label rate. Use only 15 to 20°/'o of the recommended on the label. Contact us for further information.