How to save tomato seeds...

22 March, 2014

At the farmers market the other week I succumbed to the most fabulous looking tomatoes.

I mean, who could resist these? The first two were from on place that sells about 10 different tomato types (some of which I grew for myself this year), and the one on the end was from a seller that only had one type of tomato, and only tomatoes. But they were HUGE! I mean, bread and butter plate huge. Bigger than your hand huge. I had to have one, so I bought the smallest one I could find as I already had bought more produce than I could fit in my bike panniers.

But I didn't buy them to eat them (though I did that too) but to grow them.

Unfortunately saving seed from these tomatoes comes with no guarantee. While tomatoes can with care be self-pollinated to ensure (as much as is possible) a true to type seed, these were grown amongst other toms which means with bees doing their biz, the seeds contained within may be of any kind of mixed parentage.

However, I'm prepared to give it a go.

About a week ago I chopped open the tomatoes and squeezed the juicy, seedy innards into my gorgeous weck jars. Sadly, by this time I had completely forgotten the names of each of these seeds, so I labelled them as best I could.

These were left on my kitchen windowsill to get their mould on. This needs to be done when saving tomato seeds as the seed coat contains a compound which inhibits germination. This is quite clever as you don't want seeds sprouting in your fresh tomato, nor do the seeds want to sprout there as its really not the best place for a tomato to grow. Even more cleverly this compound is broken down by mould growth, so when a tomato falls in a natural environment and the tomato decomposes, the seeds are all ready to grow when suitable conditions appear.

I mimic this by letting the tomato seeds and juicy pulp get all mouldy.

Interestingly, the black and the huge tomato  got much more mouldy than the yellow tomato.

But I figure that should be enough.

Next step is to remove the mouldy coat, which is quite easy as it all holds together and you can easily pull it off with a spoon.

Into the compost it went. Those few extra seeds will have a chance at a composty existance.

The remaining seedy liquid is surprisingly pleasant looking.

This then gets poured into a fine sieve (as you don't want your seeds escaping) so the tomatoey juices can drain off.

Then the seeds are given a good rinse under the tap.

Nice and clean.

These then got spread out onto a plastic chopping board to dry.

These steps were repeated with the other two types, with good rinsing between to ensure the seeds weren't mixed.

Now I just need to leave them to dry well, before I pack them up and add them to the seed collection.

I can't wait for next year to come round to see what these turn out to be.


  1. Wow- I had no idea about the mould! (although it makes sense) my 'fail safe' method is just to put seeds on a piece of paper towel let them dry and put them away until spring. The seeds stay on the paper towel until they are ready to plant. If I can't remove them completely I just plant with paper towel attached.... seems to work.

    1. Interesting. I've never tried tomato seed saving, so I read up in my seed saving book. But if you have success without the fermenting step, even better. I also have tried paper towel but I find they stick together more. Either way works though.

  2. I'm so so glad you posted this because I've just been drying my tomato seeds out to save! I would have been so disappointed to get to next season and find that they don't germinate. Thanks so much :)

    1. No worries. Though given Jodie's experience above it may be an unnecessary extra step. It will be interesting to hear how you go if you've already dried them. I expect they will germinate, but maybe 50% vs 80% if you ferment them though I am just making up numbers here. I'm kinda tempted to do a trial, except I have already eaten the tomatoes :)