2026

We’ve entered our second year of seed viability testing. Most of this year’s testing is of seed we saved from the 2024 or 2025 seasons; some was packaged seed from previous years that we’re curious about, and one is an experiment with store-bought seed.

The testing process is the same as last year, though the setup is on a table in my office rather than in the seedling setup in my basement. A testing nest was used, with the damp rolled paper towels inside a clear plastic bag, tucked in a rectangular plastic flat on a heating pad. A temperature probe in one of the rolls connects to a controller box, turning the heating pad on below 20 degrees C (68 degrees F) and off above 25 degrees C (77 degrees F).

Everything is based on The Seed Garden book by Seed Savers Exchange. The book details the testing procedure and includes a reference table for home testing of different seeds. I check the seeds by unrolling the paper towels every other day and count how many have sprouted. (Most rolls have 10 seeds, making the percentages simple. The larger seeds have only 5.)

The testing ended when the percentage stabilized and the seeds expressed both root and seed leaves. Ten of the thirteen tests were at 100% or 80%; only one was below 50%. The details of this year’s viability results are included below.