Growing Basil on Rock Wool with a drip irrigation system


In this blog, I will show you how to work with one of our automatic irrigation systems. The cabinet I’ll grow the basil in is the G-kit 600 Wing. The irrigation system is the automatic “drip irrigation system 600 Wing”.

I will grow 20 basil clones in the cabinet.

Growing on rock wool has many advantages. The slabs are light-weight and compact. This makes them easy to store and transport. Growing on rock wool gives you more control over the process, which – if you know what you’re doing – will lead to better results.

Because growing on rock wool requires a lot of short watering moments, you need a system that contains a pump and a timer to pump nutrients to the plants.

growing on rockwool

Drip irrigation system 600 Wing


Dripp irrigation system 600 Wing

The irrigation system I work with consists of an aluminium table, a tray (Danish tray), a 43-liter water tank, a circulation pump, a feed pump, a timer, and all the connecting material.


growing on rockwool

The parts of the drip irrigation system 600 Wing

After the alumunium grow table is set up, it can be placed inside the 600 Wing grow box. The Danish tray is placed on the table.

Inside the 43-liter water tank are 2 pumps: a circulation pump and a feed pump.

The circulation pump is running 24/7 and makes sure the nutrients in the water won’t wash down and extra oxygen is added to the water.
The feed pump is switched on and off by a timer. It pumps water to the plants through a system of drippers.
The water tank is placed underneath the table inside the cabinet.


drip irrigation system

The water tank with the two pumps, a circulation pump and a feed pump.


There are two connections on top of the water tank. The tube with the drippers can be clicked on the “supply” connection. The drain of the Danish tray should be clicked on the “return”connection.
The excess water flowing from the rock wool slabs flows back to the water tank.


The two connections on the water tank. One for the water supply and one for the return water

The water inside the tank should be refreshed once or twice per week. The tank can be easily uncoupled from the system and emptied and cleaned.

Now the system has been set up it’s time to prepare the rock wool slabs and starter cubes. The rock wool slabs can be placed on the Danish tray. Where you will place the plants you make incisions in the plastic foil surrounding the slabs.

Because rock wool is a sterile medium you want to create some soil-life before planting the basil. We do this by saturating the slabs and starter cubes with a solution of water, nutrients and root-growth stimulator.


PH and EC

For successful cultivation a proper PH and EC meter are indespensible. With a PH meter, you measure the acidity of the nutrient solution. An EC meter measures the amount of fertilizer dissolved in the water.
Rock wool has very high PH values. Because our plants do best when the values in the slabs are between 5,2 and 5,6, we need to bring the PH inside the slabs down. We do this by saturating the mats and cubes with a solution with a PH value of 3,0.
The starter cubes have been plunged in the same solution and are now placed on the mats. With the drippers, you can pin them to the slabs.



drip irrigation system

The starter cubes are plunged into the nutrient solution, PH 3


The nutrient solution can now be pumped from the water tank into the rock wool slabs. Make sure you pump so much solution in the mats as they can hold. If necessary fill another water tank.

Leave the mats overnight.


drip irrigation system

The irrigation system is set up. The slabs and cubes can soak over night


I have left the rock wool slabs and cubes to soak over night in the nutriënt solution. There should be enough soil life in them to start up the grow cycle. But first I need to drain the excess water from the slabs. I do this by carefully lifting up one side of the slab and make cuts in the plastic foil at the bottom side. The nutriënt solution can flow out from the mats and back in to the water tank. You can use the solution to water the plants for the first few days but make sure you check the PH and EC levels.



growing on rock wool

After the mats have saturated overnight, I carefully lift one side of the slab and make cuts in the plastic foil. The excess solution will flow from the mats back to the water tank.


The nutrient solution that flows back to the water tank can be used to water the plants. Make sure you check the PH and EC levels.

The basil clones I cut 10 days ago can now be planted. Just remove the plastic foil around the rock wool cubes and carefully plant the clones in the starter cubes.

The last thing I need to do before the light can be switched ON is setting the timer of the feed pump. I will set the timer to switch ON for 2 minutes every 2 hours when the light in the cabinet is on. The feed pump will pump water to the plants for 2 minutes every other hour. When the light is off the plants won’t get any water.

After the timer has been set the plug of the feed pump is plugged into the timer. The plug of the circulation pump is plugged in of the sockets of the supplied extension cord.

The timer switches on the feed pump for two minutes every other hour

Now the light in the cabinet can be switched on and you’re ready to grow.


growing on rock wool

18-2-2017 day 1 of the grow cycle

If you would like to see a video on how to set up the system and start the grow:



The basil clones have been in the cabinet for 5 days. It’s time to refresh the water in the tank.
The water tank can be simply uncoupled from the rest of the irrigation system. After I’ve thrown away the water and cleaned out the tank it’s time to refill the water tank.

I fill the water tank with water and add the fertilizer according to the instructions on the package. I’m using Canna Aqua Vega two components fertilizer because this has been especially designed for use in recirculating irrigation systems. To increase root growth I add Aptus Startbooster. With PH- I set the PH value at 5.3. The EC I set at 1,2. By adding more water you can lower the EC and by adding more fertilizer it can be increased.



De clones have been inside the cabinet for 10 days and have the most critical phase, the start-up phase behind them. All have survived, they seem to have catched on and have grown 10 cm.
Basilicum kweken op steenwol




12 Days since my last post and the plants have grown quite a bit. The leaf mass has also  grown a lot. Soon I’ll be able to cut my first harvest basil leaves.


growing on rockwool

14-3-2017 The plants are in the cabinet for 24 days. Soon al be harvesting the first leaves.


Today it’s also time to change the water and nutrients. Normally I do this once or twice per week but because of lack of time this is the second time.
The watertank can easily be disconnected from the irrigation system and emptied.


The watertank can easily be disconnected from the Danish tray and the drippers.


After the tank is removed from the cabinet it can be emptied and cleaned.

When the tank is placed back inside the cabinet and hooked up to the irrigation system it can be refilled with water and nutrients.
The PH is brought down to a level between 5,2 and 5,8. The EC is set at 1,3.



growing on rockwool


The plants have grown at least 10cm in the past week. Also they have developed a lot of leaf mass.
From growing basil in the past I’ve learned that you should keep quite some distance between the lamp and the plants. The dimmable Lucilux ballast is running at 250W. To prevent the plants from getting to high I will cut them. This will also be my first harvest.
I want the plants to remain short and become bushy. You can do this by cutting of the plants top just above an intersection. The two branches will continue to grow as main tops of the plant. After a few weeks you do this again. This is how you keep the plants short and leafy.

The main branch is cut just above an intersection.

My first harvest


In the beginning I made the mistake of feeding the plants with a “flowering” fertilizer. The nitrogen-phosphorus-potassium rates are suitable for fruit bearing plants. Basilicum is not a fruit bearing plant and we are only interested in fast growth and leaf development. That’s why I shifted to a fertiliser for “vegging” plants.


Canna Aqua Vega 2 component fertilizer for growing (vegging) plants.

The basilicum is growing very fast. I will have to cut them very soon like I did last week. I’m afraid the plants will grow to tall and get to cloose to the lamp if I don’t. But what will I do with all the basil? It looks like there will be between 500 and 1000 grams of fresh basil leaves. Throwing it away is a waste. At home in my fridge are still two large jars of pesto from last weeks harvest.
So anyone who reads this and has use for a kilo of fresh basil leaf every week can contact us.


kweken op steenwol

29-3-2017  Time for the next haircut!



The plants realy need to be cut now.  Luckily the Sicilian caterer around the corner was interested in a big bag of fresh basil.
Just like last time I will cut the plants just above an intersection so the branches will split in two new shoots. If you keep doing this consequently the plants will stay short and become bushy.
I’ve noticed that a lot of little white flowers have come up. These I will cut out as well to improve leaf growth.


Little white flowers appear on the plants


The basilplants have been in the cabinets for almost 6 weeks now. All this time water with nutrients has been pumped in to the rockwool slabs. An accumulation of minerals inside the slabs will dry out the plants and eventually poisen them.
In order to prevent an accumulation of minerals inside the slabs they need to be rinsed out. This can easily be done by filling the water tank with plain water and pump the water through the slabs for half an hour. The PH of the water has been brought down with PH- to a level between 5,2 and 5,8.
After I have left the feed pump on for half an hour I take out the water tank and throw away the rinse water. Then the water reservoir is placed back in the cabinet and refilled with water and fertiliser. With PH- I bring the PH level down again to 5,2-5,8.
Now I can finally cut the plants.

I’ve harvested 916 grams of perfectly fresh basilicum. Quite a yield when you realise I paid €2,- for 40 grams in the super market the other day.


3-4-2017 Before the harvest.


3-4-2017 After the harvest.


The harvest: 916 grams.


Mondo Mediterraneo in Amsterdam-East is going to process the basilicum.