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.
- Simply take a clean glass or plastic container that has a fitted lid that completely closes. Do not use a container that is aluminum or metal as it can interact with your seed believe it or not. (You essentially want to create a micro-environment that will keep moisture inside the container.)
- Take a small sheet of paper towel and cut to fit your container. You’ll want a piece of paper towel to cover both the bottom of your container as well as the top of your seed.
- Put the bottom paper towel into place into your container. Wetten the paper towel with spring water or dechlorinated water. (You can use tap water, but the other two options are more ideal — tap water is treated with chlorine which kills beneficial bacteria, so it could possible impact any beneficial bacteria on the surface of the seed.)
- Place the number of seeds you wish to germinate. It’s a good idea to add several extra seeds as it is rare to get 100% germination from typical seed packets. By law, seed providers are to test their seed and under ideal conditions, 85% of their seed must germinate in order to sell it to the general public. So factor in, worst case, that 15% may not germinate. If you get more seeds germinating than you need, these can be grown out and given as gifts to friends and family or donated to your local extension office who often has a team of volunteers called Master Gardeners that maintain public gardens.
- Place the second fitted paper towel sheet over the seed. It should immediately soak up moisture from the other paper towel. As far as moisture consistency, you’ll looking for the entire paper towel to be wet, but no standing water. Seeds transpire so they essentially need to “breathe”. The goal is to keep consistent moisture on both sides of the seed without letting them sit in water. Thicker seeds may need to be nicked, so if you’re unsure if your seed requires special treatment, you can check our reference sheet here. Tomato seeds are pretty straight forward and typically take 3-7 days to pre-germinate depending on the variety and the temperature conditions. Pepper seeds will swell up a bit before you see the root emerge. Eggplant seeds will also swell up a bit, but they will take the longest typically to germinate, so patience. Some can take 10+ days!