Just as a rule of thumb, never germinate with nutrients. Some say it works, and it may, but there is a risk. Why risk a process in a most fragile state of your plant's lives? Would you give a newborn baby a T-Bone steak? Not unless you are retarded.
Get a small Tupperware container and add some pH friendly water to it. If you have a refrigerator or a water filter on your sink, this will make for a good, balanced pH for the most part. Just around 5.25-6 pH on the water alone will work best. Feel free to use distilled or bottled water, however you will soon find this to be like using Huggies brand diapers for a baby to shit in when the Kroger brand would contain the excrement just fine. Add the seeds you are intending to sprout into a folded up paper towel and place it in the bottom of the Tupperware container. Add the pH friendly water enough to soak the paper towel and have a couple of centimeters accumulated at the bottom of the container. Pop the lid on half way, leaving just a small crack for fresh air flow. Place in a dark place, such as a closet, and prop the container at a very slight angle so that the water will still keep the seeds wet but not completely submerged. Room temperature or slightly warmer will do just fine. Now, the hardest part is to leave them alone for about three days. The number one rule of growing next to keeping your mouth shut is to have patience. You can check them once or even twice a day if you must, lifting the paper towel to observe them and give them some fresh air. Just make sure to keep them in the dark as this will make the new plants search for the light they so desperately yearn for.
Once the sperm tails are finally showing, you know that you are almost ready. Place them back for 24 more hours and they are now good to go! Take out your Rockwool cubes and throw them in a bowl of the same pH friendly water. Leave them alone for a couple of hours to let them soak and become saturated. When you go back to pick them up, set them on a plate. Also, the paper around them can come off at this point if you are planning on placing them inside of some Hydrotron (Lecca/Clay Pellets) and net pots. They can go directly into the net pots like this, or you can leave the paper on for now and stack the cubes in rows on a tray that has a plastic cover and let them sprout there. When placing them on this tray, you may want to use enough perlite to cover the bottom of the container that the cubes will rest on, and just add a little water to moisten it up. This will keep perfect moisture and air underneath the cubes to support the root development, and they can keep this way for a longer time than if you did not use the perlite. Remember, do not add any nutrients at this point!
If you added the seedlings directly to the net pots or other medium in which they will develop, you will want to try and use some upside down plastic cups to act as a temporary greenhouse for moisture.
Be sure to mist or water the cubes lightly two to three times a day to keep them moist, and if you are using a Bubbleponics or other hydro system that distributes water into the net pots, just let it run this way with pure, clean water--no nutrients.
And there you have it. The seedlings can stay on the germination tray for a week or more if necessary, however it is best to get them into the net pots or growing medium once the roots are springing out of the bottoms of the cubes. Remove the paper from the cubes when you go to place them into your medium. If you are using net pots, do not add your 1/4 nutrient mixture to the water until roots are coming out of your net pot(s). This procedure will work every time if you have healthy seeds. Happy growing!
Yours truly,
BLumen