Pests can be a really big issues in vegetable gardens, although the specific pests that
we have to deal with, and the damage that they can cause, can vary enormously with the
climate and ecosystem that we are growing in.
Dealing with pests can require a lot of time and resources, and methods used to eliminate
them, or at least to reduce their impact, can have some problematic side effects.
In my family scale gardens I avoid pesticide sprays and poisons, both the conventional
kind, and those that are used with organic operations, as there always seems to be a
risk of collateral damage with these types of approaches.
Depending on the pest, I prefer to use barriers, traps and in some cases I hunt them down and
kill them.
But I also like to work towards the possibility that predators of some pests could be part
of the ecosystem within and around the gardens, and can help to reduce the damage caused to
my vegetables.
I’ve had some success with this approach, but a lot seems to depend on finding an appropriate
balance between the population of the pests and the potential predators.
Slugs are one of the main pests in my vegetable gardens and they can cause a lot of damage
in some seasons.
I've tried a lot of different ways to deal with them, or at least to reduce their numbers,
and for the most part these days I use various methods to kill them myself.
There are some things that eat slugs that I could introduce, especially ducks, but they're
not really appropriate in the context of my gardens, as it is an open site that is shared
with a lot of other people.
Here in Ireland, hedgehogs are one of the main natural predators of slugs, and we've
created quite good habitat for hedgehogs around these gardens, but it’s hard to know if
they are around as they are nocturnal creatures.
A few years I caught a large healthy hedgehog in a live trap that I had set up to catch
whatever was eating my broccoli plants, and it was great to know that at least one of
these slug eating garden companions was hanging around.
But over the last few years I’ve suspected that it probably had moved on, and earlier
this year there were loads of slugs and small snails in my gardens.
I had let my guard down, and i hadn’t been making as many slug killing patrols in my
gardens as I used to, and I figured that there weren’t any hedgehogs around to help.
But more recently I’ve caught several videos of a healthy hedgehog patrolling the gardens
and i've noticed fewer slugs.
If I had use poison to kill the slugs in the past then I likely would have killed this
hedgehog as well.
But I also suspect that if I had been much more successful in keeping the population
of slugs down in my gardens by other means then this hedgehog wouldn’t have taken up
residence.
And it also makes me wonder how many slugs it would take to keep a hedgehog happy and
well fed enough to stick around, and if I'd be be willing to tolerate that number of slugs
in and around my gardens.
I've also struggled with aphids in the gardens especially in the protected microclimate of
the polytunnel where they can seriously stunt some plants.
There's a number of different methods that I've used to deal with this pest in the past,
including rubbing them off with my fingers to kill them, washing them off with a hose,
or spraying them with soapy water.
But I've also been encouraging ladybird or ladybug populations, who are great natural
predators of aphids, especially during the larvae phase when they can apparently eat
enormous numbers of aphids.
Within the diverse plantings in the Polytunnel Garden, there always seem to be a number of
ladybirds around, and when I find one in the landscape outside, I often bring it into the
polytunnel to boost the population.
But I've realised over the years that if I want to rely on the ladybirds kill the aphids,
I need to give them time to do the job, and to not react to a presence to a lot of aphids
in the gardens earlier in the season.
Apparently ladybirds need to eat a lot of aphids in order to lay their eggs, or they
won’t lay them unless there's going to be a plentiful food supply available when the
larvae hatch.
But if I use some other method to get rid of the aphids while the eggs are maturing,
then the larvae may hatch into an environment where there isn’t enough for them to eat,
meaning that fewer of them will survive or stick around long enough to reproduce again.
In order to maintain a healthy population of ladybirds to deal with the aphids, I actually
need to tolerate a certain amount of aphids in the garden, and to accept that they have
a faster reproductive rate than their predators.
I need to be patient enough to let the ladybird lifecycle catch up with the growing population
of aphids.
I do keep an eye on things, but these days I try not to worry when I start to see aphids
in this garden, and instead I try to grow healthier plants that can better tolerate
the presence of aphids.
Rats are another very common companion in gardens and farms here in Ireland, as they
are in many places in the world.
There are some health risks associated with rats being around, and some people find this
really problematic, and other people are simply really freaked out whenever they see them.
Personally, I think rats are quite amazing animals, and I don’t mind them being around,
and I've come to accept that with lots of places for them to live in a natural landscape,
and a diversity of things for them to eat, they will always have a background presence.
I get concerned whenever their population seems to be getting too high, but my biggest
concern is when they start to eat crops in the gardens, including eating the sunflower
microgreen seeds, damaging a lot of tomatoes and even eating the carrots that are still
in the ground.
Over the years I’ve use several different methods of controlling the rat population,
though I have stayed away from poisons, and I've been largely successful with keeping
their numbers down.
This year I thought I would experiment with trying to leave space to see what impact the
natural predators of rats would have.
I was hoping that if I stood back and waited, the local populations of foxes, owls and a
few species of birds would step in, and I’ve also been trying to encourage a few of the
neighbourhood cats to hang around my gardens more often.
Over the past few months I have set up a wildlife camera in a number of different locations
to see what kind of activity there might be of both rats in their potential predators.
So far I've observed four different cats making the rounds in my gardens, which I thought
would deal with the rat population quite effectively.
No doubt they are killing a few rats, but I did get footage of one of the cats sitting
on top of my compost pile eating some of the scraps, and right beside it, there was a rat
quite contentedly doing the same thing.
So I became less convinced that the cats were helping out with this, especially as the rat
population seemed to be increasing.
I haven’t seen any signs of owls, though I know there’s at least two nesting families
in the area, and unfortunately any of the other birds of prey that come close to the
gardens, tend to be chased off by the large population of jackdaws and rocks that nest
nearby.
So, for a while I was concerned that my little experiment was not going to work, and I began
to take a much more active role in culling the population of rats, but then more recently
I realised that a fox had stepped in to help.
I first became aware that a fox was making the rounds of my gardens when it picked up
my wildlife camera from inside the polytunnel and ran off with it, probably thinking that
it was an egg.
I’ve since caught other videos of this fox at night, and in the past few weeks it's been
a regular daytime visitor, even coming around when I was working in the gardens, and I've
even witnessed it catching a rat.
Now that I know that there's a fox in the area, it will be interesting to see how effective
it is at keeping the rat population down, and I wonder how many rats it takes to keep
a fox happy enough to stick around?
It seems that one of the key issues with relying on natural predators is tolerance and patience,
which can be tough with some potentially problematic pests.
If I'm going to rely on there being a hedgehog in the vicinity to help with the slugs in
my gardens, then I need to have slugs in my gardens, and probably more than a few of them.
But even a few slugs can be a problem, especially with young crops which can be seriously damaged
by slugs in a very short period of time.
I could change the approach and work to clear slugs out of only some areas of the gardens,
and to rely on traps and barriers to protect the plants that are most vulnerable, and to
try to be less concerned but watchful in other parts of the gardens.
Not so sure if I want to take this risk.
I'm a bit more comfortable with the interplay between the rising and falling populations
of aphids versus ladybirds, especially as I get better at avoiding stress in the plants
that I'm growing.
I still try to be observant and occasionally I rub aphids off of some of the plants in
the spring, but for the most part I let the ladybirds do the work of keeping the population
down, and always try to have a diverse range of habitats for these predators to live in
the polytunnel.
With the possible buildup of rat populations, I'm less certain.
I am don’t know how much I can rely on the fox or other predators, or what I could be
doing to assist them or accommodate them.
I've also been quite frustrated with the damage to crops that even a few rats can do, and
I know that some of my neighbours are less tolerant than I would be.
But on the other hand, we now have a really healthy fox hanging around, and I doubt that
would have happened if I have maintained my usual role of keeping the rat population control.under
In all of these experiences I've come to see the importance of trying to better understand
ecosystem dynamics, especially the balance of populations between pests and potential
predators, and there's so much more to learn about all of this.
The weather, seasonal fluctuations and the availability of other food sources no doubt
has been an issue, and it'll be interesting to see if similar patterns of populations
occur again in the next few seasons.
Providing hedgerows and wildlife corridors can be of benefit to creatures like the hedgehog,
but the same habitat can provide perfect cover and habitat for the rats.
An open area around the gardens and the compost pile might make it easier for the predators
to catch the rats, but it might make life more difficult for the hedgehog.
And as the ecosystem evolves and the biodiversity increases, there's always the possibility
of things preying on the predators, even with the ladybirds.
I suspect that the family of wrens that have been regular visitors into my polytunnel garden
were eating a lot of the ladybird larvae, as well as other insects.
It's difficult to understand my role within all of this, but I've come to believe that
in these cases if I intervene too much then I may need to always take on the responsibility
of dealing with these pests.
This complex interplay between lots of different species in an evolving landscape will no doubt
change in the future, and the risk of loosing cops will always be there.
For now, I am focussing on developing long term resilience and understanding, and not
just on the short term gain of the crops that I’m currently growing.
But this requires a certain amount of excess capacity and abundance, which I currently
have, in which I'm able to tolerate the lose of some crops while I figure it all out.