Checking seed viability

Will my old seeds germinate?

One of the things about growing Chillies is that each season you want to grow new varieties. There is so much diversity in Chillies.They come in different colours, shapes. flavours, sizes and a bunch of other differences. This makes it extremely difficult not to try out growing new Chillies.

With all this choice, it is not uncommon to find your seed tin or drawer crammed with seed packets from previous seasons. Nothing wrong with that  , but there is a problem. Chill seeds have a shelf life.  After a while, they dry out and die. After a while, some seeds won’t germinate if you plant them. Others seem to hang on for quite a while longer.  Do you throw them away because the packet says the seeds are out of date, or do you see what you can do with them?

We have all reached this point at some time. Do you throw the seeds out or do you see if you can get some to germinate? In my case, I always go for the latter.  I don’t like throwing out seeds.  If there is a possibility that I can rescue just a couple I will go for it.  If you are same, how do we  find out ( before going to so much effort) that at least some will germinate? Is it all not just a waste of time?

The answer we  won’t. The best we can do is to use one of these tests to get an estimate of what percentage of seeds will germinate if we plant them.  If the tests fail, we then also have an answer,  The seeds can safely be thrown out with our consciences clear

Here’s how it is done.

How to do seed viability tests


Paper towel method

This method is quicker, but less reliable than the one below. You simply need to fill a jug with room temperature water and place some seeds in it.   Check after fifteen minutes. The seeds that have fallen to the bottom are the seeds that are most likely to be viable. Use this number against the total you started with to determine your estimated germination percentages rate.

You can use the estimated germination rate to decide how many seeds you will need to start to achieve your objectives.

You could of course use this method to select which seeds you are going to plant. You can discard the seeds that have not sunk to the bottom and only plant those that remain.  Before planting the seeds, soak them in room temperature tea for thirty minutes.  This will soften their outer seeds shells and they will germinate faster.

This method works best with bigger seeds (e.g. pumpkin), so it is not the best for Chilli seeds. Smaller seeds tend to want to float!  However, if you don’t have a lot of time on your hands, it is better than nothing

To float or to sink ?


Soaking in Water

Moisten a sheet of paper kitchen towel with water.  (The sheets only need to be moist. Don’t make them too wet). Sprinkle some seeds on it.  Now place another sheet on top of the moistened sheet with the  seeds  Next, place this paper towel “ sandwich”  into a zip lock bag. Close it, but not entirely. Leave a little bit open. Place the bag into a warm place, out of direct sunlight.   Check the seeds every couple of days. After two weeks, the number of that have germinated as a percentage of the total will be your estimated germination rate,

Using this method will guide you on how many seeds you need to start. So, say, for example, you want five plants of a particular variety.  If you have used twenty seeds for viability testing and ten germinated, your viability rate is fifty percent. Therefore, you will need to sow ten seeds to achieve your objective.

The method is obviously not foolproof, but it’s a lot better than grappling in the dark. If you definitely need to achieve a minimum number of plants, consider planting even more than the ten mentioned above. There is still a chance; even after viability testing, some seeds may not germinate. So I would suggest sowing say, fifteen seeds for a greater chance of success.


I will be using both these methods to check out the viability of some old seeds. I have some Scotch bonnet seeds that I want to start, but the “plant by” date on the packet has long expired. It will be interesting to see what happens. I will report back in a couple of weeks on how it went.

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