Starting Your Grow
Now that you've learned how to produce quality nutrient water for your plants, the next step is to start growing. Where you source your seeds is beyond the scope of this guide, as every grower has their own preferred supplier. Let’s assume you already have some seeds and you're ready to start—what’s next?
For germinating seeds, I’ve found the best approach is to use rockwool cubes, net cups, and LECA pebbles. I place the seedlings in a clear plastic tote, which allows sunlight in while retaining moisture. This creates a humid environment that helps the seedlings sprout.
To prepare the rockwool, soak it in water until it's fully saturated. Then place the cubes inside the clear tote, with your seeds, and add about half an inch of the low-strength nutrient solution. The rockwool will absorb the nutrients and support seed germination. Do not use the full-strength nutrient solution at this stage. Place the tote in a warm, well-lit area and wait for the magic to happen.
Once you start seeing some activity in your grow tank and your seeds begin to sprout, you might wonder when it's time to move them out of the germination tank and into their own containers. Generally, I recommend leaving the seedlings in the grow tank until you see roots emerging from the bottom of the rockwool cubes.
However, if you wait too long, the roots may start to tangle with those of neighboring cubes—and you definitely want to avoid that. So the best time to transplant is after the roots have just begun to show at the bottom of the cube but before they start tangling with others. That’s your signal to move them into their next container.
Use the LECA pebbles to fill the space between the rockwool cube and the net cup. Use 2-inch or 55mm net cups—they fit snugly into 2-inch plumbing pipes. These are the same pipes we’ll use when the plants are ready to go outside to the big-boy systems.