For my February garden show, I talked about seed lifespan or viability on my radio show amongst other topics relative to February.
Here is a seed lifespan chart that I compiled from several charts online: SEED LIFESPAN
This is a general guideline and depends a lot on how the seeds were taken care of. I’ve had seeds germinate that were way past their prime. In fact, my giant green squash, ‘Jabba the Hut’ set a new NM State record in 2011 of 340 lbs! It came from a seed that was over 8 years old, which according to this chart, the lifespan should have been between 4-6 years old but it was the only seed I had. In fact some seeds have been germinated from tombs in Egypt centuries ago. So if you have a special seed, try it despite what the chart may say.
Below is a chart for optimal seed germination temperatures if you are growing from seed inside. It is very important you try to germinate seeds at their optimal temperature-too cold a temperature then the seeds might not germinate or even rot and too hot of temperature, the seeds may fry. This chart is also good as to what temp the soil should be if you direct seed outside.
(Zone 6a): SEED GERMINATION CHART
This is an important topic this time of year as many of us are deciding whether our seeds are too old to germinate or still good and if we need to replace them. Here is some of the info I gave on the radio show:
‘Every seed has a shelf life. You can search how long seeds can be stored and how to test their viability. Fresh seeds are essential for good germination. Older seeds have less success of germinating.
To test them, take 10 seeds and soak them in water overnight and then put them in a damp paper towel and put them in a Ziploc bag and on a warm windowsill or on top of your refrigerator (but not a sunny place, you don’t want to fry the seeds). Then in a few days check them to see how many have germinated.’ If all 10 seeds germinate, then you have 100% germination, 5 seeds would be 50% and 2 seeds would be 20% and so on. I will usually get rid of any vegetable seeds 30% or less.
In the case for old flower seeds, I just throw out the seeds in spring and see what pops up. This is from last year’s garden-fantastic but of course we had a very rainy summer so that helped!
Look on the package to see the year the seed company sold them. I have noticed that some seed companies do not put the date on the packages, in which case I write down the year I bought them on the package.
Hope this helps when making decisions about which seeds to save and optimal seed germination temperatures when starting them.