Vegetable gardeners use damp paper towels to test the viability of fast-sprouting seeds, such as kidney beans (Phaseolus vulgaris) and lima beans (Phaseolus lunatus). Flower gardeners employ the towels to start seeds that require stratification – long warm and/or cold periods – to germinate. Those include seeds of hellebore (Helleborus spp.), the hardiness of which varies from U.S. Department of Agriculture plant hardiness zones 3 through 10, and masterwort (Astrantia spp.), hardy in USDA zones 5 through 9. For all gardeners, the paper towel method – called chitting – saves space because only the good seeds are potted up and the others discarded.
Test Viability of Seeds
1. Tear two full-size paper towels from their roll. Lay one paper towel on top of the other. Write the name or variety of seeds you wish to test for viability, or sprouting ability, across one long end of each towel by using a permanent marker.
2. Dampen the paper towels with warm water, and wring the extra moisture from them. Spread them on a waterproof surface with their handwritten label facing downward. Lay the seeds on top of those towels, spacing the seeds a uniform distance from each other.
3. Roll the paper towels lengthwise with the seeds inside and the handwritten label visible on top. Place the rolled paper towels inside a 1- gallon plastic bag. Add rolls of damp paper towels to the bag in the same fashion if you want to start additions seeds in those rolls. Close the bag with a twist tie loosely enough that some air can get in the bag but tightly enough that the paper towels won't dry out. If you use a zip-type plastic bag, then zip it closed but open it at least once every day to admit oxygen.
4. Place the bag on a high shelf, atop a refrigerator or in another warm place. Wait two or three days, and then unroll the paper towels and check for signs of roots on the seeds, which indicate germination. Pot or plant in a garden all seeds that are beginning to germinate, placing them at the same soil depth as the one at which you usually would sow them and ensuring their roots aim downward. Return the other seeds to their rolled, damp paper towels in the bag, and continue to check them every day.
Prepare Seeds for Stratification
Although not original to him, the paper towel method of stratification was endorsed by Professor Norman C. Deno, who used it for the seed germination experiments he detailed in Seed Germination Theory and Practice. Deno recommended stratifying seeds by using paper towels that retain their strength when wet, thin polyethylene plastic sandwich bags that are closed with twist ties rather than zippers, and a fine-pointed – rather than blunt-pointed – permanent marker.
1. Remove a single, full-size paper towel from its roll, and place the towel on a flat surface with the towel's shortest side nearest you. Fold the paper towel in half. Turn the folded towel so that its shortest side is nearest you again, and fold the towel once more. Repeat this process one more time, and the paper towel should have a greeting cardlike shape.
2. Write the name or variety of seeds you want to stratify, placing it on the front of the folded paper towel with a permanent marker. Dip the folded paper towel into a bowl of lukewarm water to dampen it. Squeeze out excess water, smooth the towel into its greeting card shape, and insert the seeds inside the "card."
3. Repeat this process for each type of seed you wish to stratify. Stack several of the folded paper towels, or paper towel cards, containing seeds. Place the stack inside a sandwich bag with the paper towel cards horizontal so that the seeds don't fall out, and fold the bag's open end under to help keep the paper towels damp.
4. Place the bag on a high warm shelf, in a refrigerator or in a rodentproof container outdoors, using the location that matches the kind of stratification the seeds need. Check the bag's contents at least once each week, ensuring the paper towels remain damp and to remove and pot up seeds that have begun to germinate. Continue to position the paper towel cards horizontally in the bag so that the remaining seeds don't fall out.
If a seed begins to root into a paper towel, tear out that bit of the towel and plant it with the seed. The paper will disintegrate in the soil.