I like to know if a seed has germinated before it ever goes into soil or a piece of hydroponic Rockwool. There’s an easy way to know if you have viable seed and that is through a technique that simply requires a sheet of paper towel, a container with a lid, water and a consistently warm location 72ºF-76ºF. You can learn more about how to set up these pre-germination conditions on our blog here, but if you’re already familiar with this method, here is a quick visual of what you’re looking for with pepper seeds and when to transfer them to either soil or Rockwool (Rockwool is used for soilless hydroponic / aeroponic growing systems).
The seed that is circled in green is ready to gently transfer to soil or Rockwool using a sanitized tweezer. (To sanitize your tweezer, simply clean with rubbing alcohol.) The seed circled in yellow shows swelling and indicates that you should probably check it the next day as the root is getting ready to emerge.
The other seeds are slightly swollen showing that they are still in the process of germinating. Do not give up on seeds that are slower to germinate — sometimes they can take up to 10 days even when you are providing ideal conditions. Check moisture daily and if paper towel smells funky, swap out for a new paper towel and rewet and put back into germination chamber container.
Below is a photo showing germinated seed that has been placed into Rockwool (see number one below). If you are growing in a hydroponic growing system such as a Tower Garden or Aerogarden, you’ll want to place your seed in Rockwool instead of soil. (Coco Coir is also a good alternative growing medium for hydroponics or aeroponics assuming it has support to hold material together such as in a mesh net.)
I like to cover my seeds with vermiculite. Some hydroponic growers insist that this step isn’t necessary, but I like to make sure my seeds receive adequate moisture throughout these early stages of growth especially. Strong healthy seedlings, make for strong healthy plants. I use this process for pepper, tomato, and eggplant seeds and any seeds that are not super small. Remember, some seeds need light to germinate (like lettuce), so be sure to reference our cheat sheet before starting seeds to know if your seed needs light, no light, or if it doesn’t matter.
Rockwool is a fantastic growing medium as it has air pockets and is good at holding water. Keep moist, but not sitting in water.
Hope that helps! Remember, we have a great assortment of hydroponic-adapted tomato and pepper seed available in the seed store. Be sure to check it out!