I have been growing onions for many years, and it’s usually a productive and resilient
crop for me, especially when grown from spring planted sets.
But this season I was quite disappointed by the yield and quality of many of the onions
that I grew.
I'd planted the same batch of sets, on the same day, in seven different areas or gardens,
but got really divergent results.
I’m quite intrigued by the reasons why this would have happened, and it seem that there
was number of different overlapping issues.
The worst results came from the sets that I planted in the new polytunnel of the Black
This is usually quite a successful crop when grown under the protection of plastic, with
higher yields, faster growth and an earlier harvest, but I was really disappointed by
this batch.
Part of this is likely due to the poor soil fertility in this garden, an issue that I’m
working to fix, and it also probably contributed to the bad case of downy mildew that hit the
entire crop.
But, probably the biggest factor was my failure to weed enough, which caused these onions
to suffer from some serious competition.
I just didn’t give this crop enough attention, which is really disappointing, especially
as these onions took up an entire bed of this really high value growing space.
Spring planted onions in Extensive, Intensive and No-Dig Gardens all did very badly, with
less than 30% of yield that I was able to get last year, and worse for any year I have
records for.
It seems that weather was one of the biggest factors here, as we had a cold and wet spring,
with strong winds that caused a lot of damage to the leaves, and all of this seems to have
contributed to really bad cases of downy mildew.
And then suddenly the weather transitioned to a really dry period.
All this was exacerbated by some weed pressure, as I struggled with keeping up with these
regular tasks with all extra watering I was doing.
The weeds would have caused increased competition for nutrients and water, but I can’t discount
the possibility of issues with the overall fertility, as I suspect there are some deficiencies
in the soil of each of these gardens.
The batch of onions that I planted outside in the Black Plot had similar issues with
weeds, but because it was in a more sheltered location, they weren’t damaged as much by
the winds in the spring.
But I didn’t water these onions at all, even during the extended dry period, so I
was a little bit surprised when the average size of the bulbs and the overall yield that
was harvested from this batch, was on par with the other three gardens that I did water.
There may have been slightly better soil fertility, or slightly less weed pressure at critical
times in the development, or its possible that onions just don’t need so much water
after they reach a certain stage in their development.
But whatever the factors involved, I was still disappointed in the harvest.
On basis of these four outside gardens, I would probably mostly blame weather for the
poor yields, but the onions growing in the Simple and Polyculture Gardens went against
this trend.
While the harvest from SI garden was less than it was last year, the drop wasn't nearly
as much as it was for the other gardens.
The kg/m2 yield of onions from the Simple Garden was more than twice average of other
four outside gardens, and more than 60% higher than from the Intensive Garden.
And the individual onions were on average more than twice the size of what was produced
in the other four gardens.
Perhaps this was due to this batch being slightly more sheltered from the wind, or there was
perhaps better soil quality and fertility.
But I suspect that the main reason is that there was substantially fewer weeds, even
if I wasn’t so attentive with my weeding.
The garden bed that these onions were grown in, had been fully prepared in the autumn,
and then covered with a ground cover fabric through the winter and right up until just
before the sets were planted in the spring, and I think this helped a lot with the weed issues.
In a similar way the bed in the polyculture garden was much more thoroughly weeded while
the onions were growing, in order to prepare the soil for a broadcast sowing of carrots
and parsnip, in amongst the onions and garlic.
The late spring also meant that I delayed this intercrop sowing of carrot and parsnip,
which effectively gave much more space to each of the garlic and onion plants while
they were actively growing, than they would have had in any of the other gardens.
This extra space meant a bigger root zone with more food, less competition and less
stress, and this really seemed to have made a difference in what was otherwise a tough
year for this crop.
It’s difficult to compare the yield from the Polyculture Garden with other gardens,
as all the plants were mixed in together.
But even if you ignore the fact that these onions were sharing the same space with garlic,
and then carrots and parsnip, the kg/m2 yield was slightly less than the Simple Garden,
but still more than the other outside gardens.
It’s interesting to compare the number of onions that I harvested to number of sets
that I planted at the beginning of the season, and it’s been a lower percentage this year
than it has been in recent years.
Part of this is due to some of the onions rotting at their base where they touch the
soil, which seems to be a weather related issue that was common to all the gardens.
Another factor is when the sets themselves are actually removed form the soil, this can
happen by the young developing roots pushing the set right out of the soil, and it seems
to have happened more this year than in previous years, and perhaps I just didn’t plant them
deep enough.
In the past, I’ve had lots of sets pulled out of the soil, and I suspect that birds
have done this, so now I make sure that I cover all of the sets for at least the first
few weeks in order to prevent this.
But I noticed something really strange in the simple garden this year.
A lot of the sets were pulled out of the ground and clustered together, as if something was
collecting them.
But this was under a crop cover and so it couldn’t have been birds, I can only suspect
that it was a mouse, or a rat, or perhaps even a hedgehog, but I still have no idea
why it would have done this.
Having to replant the sets would of course delay the start of the growth of the onion,
and any roots that were developing would probably be damaged as I pushed the set back into the
soil, which would likely cause stress for the plant for the rest of the growing season.
All of this would have reduced the size and number of onions harvested from all of the
gardens, but if it hadn’t been for the strange pest behaviour in the Simple Garden, the yield
from this garden might have been even higher.
Perhaps it’s not really fair to compare these spring planted crops that were grown
outside, to a crop of overwintering onions that I planted in the shelter of the Polytunnel Garden.
Overwintering in this kind of shelter, during the typically mild Irish winter offers plants
many opportunities to grow, the extra warmth and the lack of wind usually lead to bigger
and earlier harvests.
But this season I also had good weed control, and enough watering for the most part, and
really good soil fertility.
All of this enabled me to harvest 10.5 kg of onions from each square meter of bed, which
is more than 2.5 times the yield of the Simple Garden, and more than seven times the yield
of the Extensive and No-Dig Gardens this season.
It also produced quite large bulbs, despite the intensive planting, with sets spaced quite
close together.
It may not be a fair comparison, but it’s really useful for me to be aware of how good
a crop can get, given the right conditions.
This season has also been an interesting lesson in how poorly crops can grow, given a combination
of poor weather, inadequate weeding, and fertility not being as good as it should be.
And this year I’ve had the full range of results, from really poor, to some of the
best onions I’ve ever grown, and there’s lots of learning possibilities from all of it.
One of the great parts of this RED Gardens Project is being able to grow the same crop
in multiple different gardens, and when things go poorly, it's often a more valuable learning
experience than when things go well.
Although I’d rather only share my successes, I think it’s important to share and explore
the reasons why things didn’t go as planned; that’s a really important part of this YouTube Channel.
If you appreciate this approach, please consider becoming a Patron on my Patreon Page, linked
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Any contribution you make, will help me to continue with this fascinating project, but
more importantly, thank you for watching.