Like so many growers, I have developed quite a collection of seeds
Some I don’t grow very much of, or the packets that I bought were too big,
and some of the seed packets were of vegetables or varieties that I have decided to not to grow
any more, and the packet ends up just sitting there, sometimes for many years.
And then there are the seeds of the variety trials I have been doing,
and seeds that I bought for other variety trials that I haven’t got around to doing yet,
as well as some seeds I saved over the years. Add to all of that, I stocked up on extra
seeds in the last few years in anticipation of supply constraints,
and in total I have seeds for almost 300 varieties of different vegetables, and several packets of
different ages for quite a few of the varieties. That is lot of seeds to keep track of,
and to use up, and I wanted to know which of the packets were still strong and viable enough
to be able to grow this season, and which ones were not really worth keeping around.
So over this past winter I have been methodically working through this collection, testing
each batch of seeds of each variety of each vegetable that I have, with some useful results.
I have never done a proper seed germination test before, and occasionally had poor germination or
gaps in the crops in the crops that I was growing, but was never quite sure if it was because the
seed was too old, or of poor quality, or is it was due to pests, cold soil or some other factor.
I am not really sure if I can rely on the quality of the seeds that I’ve been getting from different
suppliers, and I would prefer to know that the seeds are good quality before I sow them.
The guidelines for how long seeds from different vegetables are expected to last can be useful,
but I have experienced seeds that have not lasted as long, and other seeds that have lasted quite a
bit longer than the recommended number of years. So, I figured the only way to really know is to
test them, sowing a specific number of seeds from each package, setting them to germinate in close
to ideal conditions, and then counting the number of seedlings that appeared, as well as noting how
vigorous and uniform the seedlings were. I also wanted to know which seeds would
probably last for at least another year or two, and to make a note of the seeds that I
should probably sow extra of because they were not great quality, but not worth replacing just yet.
A few years ago I started buying excessive amounts of seeds, mainly in anticipation of
Brexit cutting off my usual seed suppliers in the UK, and the disruption that eventually caused.
In many cases I purchased the next size up in packages, which was often significantly
more than I could use in multiple seasons, and I wanted to know if all this extra seed
was worth keeping, or if it was still good enough to share with other people.
A good example of this was the multiple packages of the
5 different varieties of lettuce seeds that I have been growing.
According to the common guidelines, lettuce seeds should last up to 5 years, or should
be expected to have sufficient germination rates up to 5 years, and some of the seed
packs that I had were getting close to that age. I carefully counted out 20 seeds from each pack
and sowed them in a pot of seed compost, in clumps of 5 to make things easier.
There was a huge difference in the germination rates and the vigour of the seedlings, and
in some pots no seeds germinated at all, and I even repeated the same test to make sure
it wasn’t because of something I did, and the results were fairly similar.
So I ended up throwing out a lot of lettuce seeds, some of which wasn’t that old, but thankfully one
pack of each of the varieties had really good germination, apart from one variety that had
poor germination, even though I bought one of the newest seed packets only in the last year.
And I had similar issues with the carrot seeds, which I had stocked up on extra seeds for a few
varieties, and I ended up throwing out a few batches that did not have great germination,
which felt like a real waste, although some of them were older than the 3 years
normally given for carrot seed viability. It is possible that these seeds could have
been exposed to too much heat at some point or some other factor that could
have degraded their quality while in storage. But I also have no idea how old the seed really
was, as the seed packages generally only specifies the year it was packed, but no indication of
when the seed was actually produced, or how strong the seed was to start with.
One of the biggest variety trials I have been doing is with tomatoes,
where I started with growing 54 varieties 2 years ago, and grew 28 varieties last year,
most of which I saved seeds from. I tested all of the seeds that I saved,
and found most of them to be really strong which is what I would hope for and expect, but some of
the varieties had fewer seedlings germinating. I think this is because the some of the seeds
had started to sprout in the cleaning stage of the seed saving process, but
I still have enough seeds germinating to make it worthwhile, I just need to sow more than I need.
I decided not to do a germination test on all of the original packets of seeds that I had bought,
as some of them I doubt I will ever grow again, and for the others I have my own seeds, and
assuming there hasn’t been any cross pollination, the original seed packets are now redundant.
I am not keen on throwing this diverse resource away, just yet, so will put them into longer
term storage, without knowing how viable they are or when they might ever be used.
I also did a trial of 15 different varieties of Bush Beans in the same polytunnel last year,
and saved seeds from all of them. Beans are generally fairly reliable seeds,
but I was not sure about the conditions so I wanted to test them all before using them next
year, or sharing with friends and neighbours. Most of the batches of seeds were very strong,
but I am not sure why one variety had really poor germination,
so it was a good thing that I checked. And I also tested the seeds from the original
packets that I bought, more to see I there was any difference with the ones that I saved,
and they were fairly good, though not as strong as the new seed that I had saved.
I am not sure what will happen to all of these seeds I saved, as some of the varieties I will
likely not grow again, and I’m not really keen on passing them on to other people if
they didn’t work well for me, but I will likely keep at least a portion of them in reserve,
and may end up getting rid of the original packages so they
I grew a number of different varieties of Climbing Beans two years ago,
but I only saved seeds from one variety at the time.
I sowed 10 seeds of each of the packages, and some of them had really poor germination
and I decided to just get rid of these seeds, and others were still fairly strong,
or enough of the seeds germinated to make it worthwhile growing them again this season.
It was interesting that the seedlings grown from the seeds that I did save two years ago,
were significantly stronger than the seedlings grown from the original package,
even though all of them germinated. This is a sign that these older seeds
are degrading in viability, which I guess is to be expected as they are at least 4 years old.
Before the trade restrictions imposed by Brexit were put in place I bought a lot of seeds of
different varieties of squash, getting most of the varieties that I could find, in anticipation
of trying to find varieties that will actually grow well in the climate we have in Ireland.
Because there are so few seeds in some of the packets, I decided to test them by
sowing only three in a pot, which isn’t enough to really determine the viability of the seed,
but I only wanted to see if I could get a at least one good seedling out of it.
And most of the seeds were fine, and I think the significant difference in strength of
the seedlings was do to the differences in varieties rather than the quality of the seeds.
In hindsight I could have done all of this when it was time to sow the crop later in the spring,
and just discarded any that didn’t germinate, and this would have saved the effort of testing,
and saved some of the seeds. But because I have so many varieties,
and many of them won’t grow well at all in our climate, most of the seeds will probably
go to waste anyway, but that is a consequence of this kind of search for appropriate varieties.
I probably could have done the same thing with all of the different varieties of onion
seeds that I have collected, and just waited until I was sowing for the trial this year,
and planted out whatever germinated. But because there are so many seeds in
each package, and that onion seeds are only supposed to last a year or two, I wanted to
see if any of them would actually germinate, as I bought most of them a few years ago.
I was pleasantly surprised that a lot of the seeds germinated well,
though I didn’t have really fresh seeds to compare them too, so I think if I really
look after the seeds left over after this season, they might last a few more years.
And the beetroot seeds which were purchased for similar type of trial, also did quite well,
and these seeds would generally be expected to last for up to 4 years or more.
Because I plan to direct sow all these varieties in the trial this year,
it was good to find out that several of the batches of seeds had really poor germination,
and I just got rid of them rather than having the taking up space, as I probably have enough to try.
And with so many seeds in each of the remaining packages, I will be able to use these seeds for
the next few years, and even have enough to be able to share with friends and neighbours.
With a lot of the other types of vegetables, flowers and green manures, I only had one
or two packs of seeds, so it was a bit harder to determine how vigorous the seedlings were.
But with the brassica family of plants it was very interesting to have such a wide range of
seeds from many different types of vegetables, but because they tend to be so closely related,
with very similar seeds and seedlings, it was useful to compare them.
Some were very strong with full germination and others were not great,
and some seedlings even had damaged leaves, and although they will likely produce a crop,
they might be a bit slower to get going. If the seedlings were really bad, and I wasn’t
really interested in growing that variety again, or if the replacement seeds were quite cheap, then
I discarded the pack and replaced it if necessary. But some of the seeds from varieties I want to
grow are quite a bit more expensive, and in some cases I have had trouble finding more
seeds of these varieties now that Brexit has cut off access to my usual suppliers, and will
keep sowing these seeds, but make allowances for the poor germination and slower initial growth.
I saved a few other batches of seeds last year, from different types and varieties of peas and
beans, and I don’t think it was really necessary to test them, but I did anyway, and wasn’t
surprised that they all germinated quite well. With larger seeds like these, it is easier to pick
out only the really good ones, saving the larger seeds without any signs of damage or blemishes.
Saving only the best seeds is definitely a good strategy for getting strong seedlings,
and I expect this strategy might also allow the seeds to remain viable for more years.
And I did this when I had saved seeds from a large range of different pea varieties ten years ago,
but that diverse collection of seeds has been sitting around since then.
I sowed 20 seeds of each of the 24 varieties of peas into pots and waited for them to germinate,
but not a single seed grew, and digging into the growing medium a few weeks later,
all I found were the rotting remains of the seeds. So I threw out the whole collection,
and all of the effort that went into growing and saving the seeds was wasted.
This was a tough lesson to learn, and it showed me that I need to be much
more mindful about maintaining the varieties, resowing and saving a new batch of seeds on a
regular basis, or else I risk losing the variety. But then not all varieties are worth keeping, as
the variety trials that I have done have shown me, letting go of some varieties is just inevitable.
This does highlight the need to be more careful with the storage of seeds.
After all of this germination testing, I have been using silica gel to make sure
the seeds are properly dry before vacuum sealing a lot of them into airtight bags,
which has the added benefit of reducing the amount of space that they take up.
I’ve started using the freezer for longer term storage of some of the seeds,
especially the packages that I am not planning to use this coming season.
And earlier this week I found out that the use of oxygen absorbers
to remove all of the remaining oxygen from the sealed bag can apparently really help
prolong the viability of the seeds in storage. All of this is part of the process of rethinking
how I store seeds, and figuring out the best ways to store the seeds that I use regularly, several
times a season, and how to separate those from the ones that I only need to use for one sowing
a season, and to separate them from the packages that I might need at some point in the future.
All of this is better than storing them all in one crate, especially if they are slowly degrading.
I would rather not do another germination test of most of the seeds like this,
because it was a lot of work, but it has been useful to establish a baseline test,
to figure out what is worth keeping as I shift into a phase of trying to take much better care
of the collection of seeds that I have. I might still do occasional tests of seeds
that I buy in, to make sure they are good enough quality, but all of this is really
important to make sure that money, seeds and past efforts are not wasted, and that the seeds that I
do sow in the gardens will consistently produce strong and vigorous seedlings.