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Seed saving for beginners – saving tomato seeds

Seed saving from many vegetable and fruit varieties is incredibly easy, and tomatoes are a great place to start. This is because the flower pollinates itself as it opens, so crosses are rare. Not impossible, however, and it’s always best to err on the side of caution any time you want to be sure that the variety will breed true.

Lots of the tomato seeds that can be puchased at your local garden centre are ‘F1’ varieties, meaning they’re a ‘filial’ cross between two different parent plants. Avoid saving seeds from these, as they will not breed true – and if you’re saving seeds in order to preserve particular characteristics that you like, it’s a waste of time.

Decide which plants you’ll be seed saving from

First, and fairly obviously, make sure you’re saving seeds from your favourite varieties! The plants should be disease-free, and the fruits themselves slightly over-ripe. The actual method for saving tomato seeds varies according to who you ask. There are basically two methods, fermentation (which can save loads of seeds at a time) and the more straightforward drying, which is fine if you want to save just a few seeds.


There is a gelatinous coating on the seeds that contains chemicals which slow or even prevent germination. It can also harbour harmful bacteria which will then affect the seedling. This can be removed by fermentation.

To do this, slice a tomato around its equator and scoop the seeds out into a water-filled jar. Leave them there for at least a day. Some say you should leave the mix for 5 or 6 days, until a mouldy scum has developed on the surface, then pour it off, rinse the seeds, and dry them. Others say this is far too long and may result in diseases (canker, for one) spreading to the seeds themselves. In fact, a single day is enough to soften the grip of the coating, and a firm rinse in a fine sieve will then remove it altogether.

Don’t bother to hang on to any seeds which are still floating, as they won’t germinate. Pour them off with the excess water.

However long you leave the seeds to ferment, rinse them several times to ensure all remnants of the coating have been removed. Then spread them out onto a paper towel or plate until they’re completely dry.

tomato seeds, image

Spread seeds out on a paper towl to dry


This method is much less work than the above, and in just a few minutes you can save enough seeds to fill next year’s garden with tomato plants.

Cut the fruit open, as described above, and scoop a few seeds out onto a paper towel. Squeeze a seed firmly in the towel, and the coating…pops right off. The seed can then be laid out on another towel, or paper plate, as when using the fermentation method.

Some people may worry that this method, while removing the coating, won’t remove the harmful bacteria. In fact this doesn’t seem to be the case.

Seed lifespan

Tomato seeds remain viable for 2 to 3 years if stored properly, which means completely dry in a cool, dark place. If you have a favourite open pollinated tomato, and especially if it’s an heirloom type which may be difficult or impossible to find again, do yourself a favour and save some seeds. Then you’ll be able to enjoy them every year!

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2 Responses to “Seed saving for beginners – saving tomato seeds”

  1. kevs says:

    Hello Mark,

    I stumbled across this website a few days ago and I’ve enjoyed reading through it and have learnt plenty of new info. It’s always good to read text written by those who know what they’re writing about rather than those simply trying to sell me something. Bravo – I hope you continue to update and expand it.

    I do accept that this site is written for those who are fairly new to gardening. With respect though, I must refute your statement above that saving seeds from F1 tomatoes is a waste of time. The F2 generation is where the genetic segregation happens; results can thus vary widely. However, it’s usually possible to find plants that are fairly true to the F1 progenitor and even if that doesn’t happen, there’s absolutely no harm in experimenting. This is how new plant varieties arise. So please don’t discourage your readers from saving F2 seeds by propagating myths like this one. Another thing: failed experiments can always be eaten! :-D

    Here’s a fascinating article illustrating the results of a possible F2 grow-out: http://daughterofthesoil.blogspot.co.uk/2006/09/today-in-garden-tomato-weirdness.html

    You might like to know that I’m growing out two supermarket varieties; one is now in the F5 generation and is still segregating for fruit shape. Another I’m growing is a green-when-ripe cherry variety in its F2 stage. It will be exciting to see and taste the results of this grow-out.

    Best wishes, and thanks for an interesting, informative website,

  2. Mark Gatter says:

    Hi Kevs,

    First, many thanks for your reply, and I’m very happy to hear you find the site interesting! Second, you are absolutely correct in saying that F1 vars can open the doors on new and potentially useful results. However, this is intended as a ‘beginner’ site, as you noticed. The thought behind this post and the others in the series is that if someone wants to produce seed that grows more-or-less true to type then non-F1 varieties are the way to go. Many gardeners only have room for a couple of tomato plants and so it’s important for them to know roughly what they’re going to get. I think the beginner is likely to be discouraged if they save seeds only to find that the results vary considerably from what they expected.

    Segregating for particular features over several generations, as you are doing, is much more advanced stuff. I suspect you grow more than two tomato plants each season in order to follow the results through to F5!

    The point you make regarding the use of F1 varieties is valid and important and I will try to address the (considerable!) potential in saving F1 seed, and thus breeding new varieties, in the blogs to come. Thanks again for your post, and please let us know how the F5 plants turn out. If you have photos of your various results I’d be very interested in seeing them, and (with your permission) possibly including them in something in the future.

    Best wishes, and good luck with your tomatoes!


    PS – Incidentally, as a result of your comment I’ve changed the wording of the blog slightly in hopes of making things a little clearer.

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