Can I sow older seeds? Seed viability test

As always January for us is about getting ready for the coming season, usually beginning with the day in the warmth of the indoors, with a cuppa and a biscuit browsing seed catalogues and websites deciding on what we are going to grow in the coming months. There will definitely be tomatoes, but what type? Shall we try something different this year? Do we have the space for … It might just be the second-best time of the season, the first best being potting up the tomatoes and peppers into the final pots. Runaway winner for me.

Check our video for our simple guide to testing seed germination rates: https://youtu.be/H3eorBGPucg

So, this has led to a small issue in our house (green or otherwise) where we ended up with a box full of seed packets because you know, every January… Do you recognise this situation? Well, hopefully, we can now help with this, and hopefully, also help you from spending so much on seeds and it goes like this.

I have all these seeds, some are past their sow by date, do I
a. just use them, it’ll be fine
b. I have to buy more

So let’s think about these two situations, first, let’s look at (a). Yes, you absolutely can just use them, and chances are you will probably get plants from the seeds you sow. Hurrah! BUT… as the seeds degrade, you will have less success with those seeds, meaning a waste of time, effort, soil etc as you sow seeds that don’t take. So that makes it easy then, jump to option (b)? Well not quite… let’s take a step back here.

So if we sow seeds that aren’t going to germinate or at least not in the numbers we expect, that is annoying, frustrating and a waste, but throwing away all old seeds and buying new every year is expensive and wasteful too. If only there was a way to know?

Well, that is where we come in to help you, there is a way to know how likely your seeds are to germinate and it’s easy to do.

Seed viability test

So you’ll need

  • sandwich bag or other resealable plastic bags
  • marker pen
  • paper kitchen towel
  • water

So the idea of the seed viability test is that we are able to test germination on a small number of seeds and from that work out a likely percentage for germination. It’s really easy. Basically, write the type of seed and date on the plastic bag and then turn it over so there is a clear, unobstructed view of what is inside the bag (there will be shortly).

Next, damp the paper towel down, You do want it to be properly damp but not sodding wet. I use a spray bottle of water for this.

Place the paper towel inside the bag and place 10 seeds onto the towel, make sure there is space between each of them.

Press the bag down onto the seeds to make sure they make good contact with the damp paper and lastly, seal the bag closed.

Now place that bag somewhere warm, face down so that the seeds are protected from the light and wait. If your seeds are viable, you should see some germination within a fortnight (depending on the seeds). Because we’ve sown 10, it is easy to work out the percentage of our seeds which have germinated and from there we can say that they are worth sowing or not. Generally, it is agreed that 50% and above is worth using, you will just have to sow enough seeds (taking the percentage in mind) to ensure you get the number of plants you need.

As a bonus, you haven’t wasted any seeds by doing this as you can plant the seeds which germinate. Win-win in my book.


One thought on “Can I sow older seeds? Seed viability test

  1. I’m not that much of an internet reader to be honest but your blogs really nice, keep it up! I’ll go ahead and bookmark your website to come back down the road.

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