germinating old tomato seeds
Have you ever found a pack of tomato seeds from a year or two ago and wondered if you could germinate those seeds and get them to grow? If you’ve ever had this happen, the answer is definitely try it!
Yesterday, I uncovered some seeds that I thought were lost to time. One was a tomato I had been breeding myself; another was a commercial packet that contained seeds that did not match the variety. It was from a highly respected seed firm, so the tomatoes were either 1) a mis-labeled pack or 2) crossed seeds. I’ve had crossed seeds before from a commercial pack, and it’s always exciting to see what might grow out.
How old are these seeds? They’ve been patiently waiting for 5 years!
How Long Do Tomato Seeds Last?
I’ve had this happen in the past, and I’ve successfully germinated seeds that I had for 10 years (see a previous post on seed germination) . So, I’m thinking that because the seeds were in a cool, low-humidity location, my 5-year-old seeds should germinate OK.
I don’t expect a 90% rate — probably more like 70 to 75%. But hey, I planted 8 seeds of each of the two packets, so even if I get just one or two good, sturdy plants from each, I will be thrilled. 🙂 (More is better, though, so I can select the healthiest plants to work with.)
Germinating Old Tomato Seeds
Because I want the seeds to have the best possible chance, I got together the following:
- 3-ounce paper cups
- Seed-starting soil
- Liquid kelp, diluted to 1/3 strength
- Windowsill greenhouse
- Seed germination heat pad
- Pair of scissors
- Plant labels
With the scissors, I cut slits in the bottom of the paper cups (for water drainage). I filled them to the top with the seed-starting soil and placed each cup in the windowsill greenhouse. When all the cups were filled, I took my liquid kelp mixture and soaked the soil, letting the water run out the bottom.
I let the cups stand for a few minutes, then lightly pushed the soil down. When I was satisfied that the top of the soil was moist, I put on the soil surface 4 seeds per cup. (Normally I’d only plant 2 per cup.)
I put a layer (maybe 3/8 inch thick) of the seed starting soil on top of the seeds and once again, lightly pressed down.
I added labels to the cups with the name of the tomato, and filled the windowsill greenhouse with enough water to come up 1/8 inch up the sides of the cups. That would provide enough water to make the seed-starting soil moist all the way through the cup, to the top.
Put the top on the greenhouse (to keep the humidity up) and set the whole kit and caboodle on the seed germination heating pad, which would gently warm the bottom of the greenhouse, and by extension, the soil and seeds.
How Long Will it Take?
Good question! Normally it takes anywhere from 3 to 10 days to germinate tomato seeds, with about 5 days being average. Given that these are older seeds, I don’t expect to see signs of germination for 5 days at the earliest, 7 days on average. Therefore, I wait impatiently. 😉