I know that for sure there would have been many more slugs & snails that were turned away and not fried by the fence. Having to use a brush to clear the wires of crispy bits every day or two will P me off soon so, after all the other urgent spring jobs are done, I might get around to pulsing the DC or adding the 3rd wire as previously suggested by a poster.
At least it's working. Now I just have to use beer traps for a dew weeks to shift all the gastropods that are already in the beds out of their silver beet hotel and off to gastropod heaven :)
snoopy221,
Sep 28, 8:12pm
A **moot point** it appears in the pics that-as one would expect there is an anode and a cathode and water. I.E. it appears one wire is corroding more than the other. Changing polarity once a month may well give longer wire life .
iluvmuse,
Sep 28, 8:15pm
have you tried a lower voltage? maybe 4 D's at 6 volts would be enough to repel without frying
mark_g,
Sep 28, 8:30pm
No I've tried nothing else yet. What I have definitely works - but has it's own maintenance issues.
To snoopy - yes - another fine idea! If the stainless wire looks like corroding I might try changing polarity. You are quite correct - I definitely noticed that on both of my beds one wire corroded much more than the other (I think it was the neg wire - electrons flow neg to pos from memory).
To ilvmuse - a similar theory was suggested; which was to add a third wire with a lower voltage on it. So 9v between middle and top wire, and 1.5v between middle and bottom wire. And this is on the cards as well.
There's two or three really good constructive ideas that have been suggested by posters in this thread - so I'm pretty happy about that.
I was briefly toying with the idea of low voltage AC on the wires, via a transformer from the mains - but of course when the power goes off then it's all on for the slugs so that idea is out.
snoopy221,
Sep 28, 8:34pm
To snoopy - yes - another fine idea! If the stainless wire looks like corroding I might try changing polarity. You are quite correct
So easy to have 2 plug ons for the battery and change them monthly
K
Further edit possibly a small zinc block on either wire (As with marine sacrificial anodes) may be worth a *crack* Nigel.
Edits to add done a LOT of marine stuff in my time and yip **spotted it**
sooby,
Sep 13, 7:40pm
Hey mark_g, loved hearing about your anti-snail electric fence in the other thread.
Any chance of some photos of it in action & perhaps more details?
I'm sure I'm not the only one interested in it!
tourer100,
Sep 14, 8:59am
It's on YouTube
mark_g,
Sep 14, 7:57pm
I've just received some stainless wire to replace the rusting galv stuff. So I'll do that - hopefully, weather and a few other things permitting - this weekend, and get you some pic's.
It's just two wire rings around the raised vege patch, stapled to the external sides of the wood. The rings are about 12mm apart. 1 ring goes to 9v battery pos and the other goes to battery neg. Battery housed in a little weatherproof (not really!) plastic box.
mark_g,
Sep 14, 8:06pm
Not very tech savvy these days. What/where is the easiest way to upload a couple of pics?
cleggyboy,
Sep 15, 1:19pm
So what do you use to insulate the wires from the wood, surely if the wood is damp it would short to earth. Yes I'm interested as well, got a raised garden to protect.
ira78,
Sep 15, 1:42pm
Even damp wood isn't very conductive and 9v isn't much voltage.
Yes, poster #7. Mine looks like that - but better (yes I'm serious - that's ugly).
Yes. I found the one 9v battery lasted all spring-summer. So I think the current drain when things get wet must be very very small. i.e. not worth worrying about.
The one pain in the whole system is that too many gastropods get fried, which means their remains get left sitting across the two wires. Which means I have to whip round the raised patch with a stiff brush every couple of days to remove them. It's easy but it P's me off and the prolonged current flow does mean more draining of the battery, but more importantly the prolonged electrolysis means more corrosion product at that point along the wire.
This is why I'm thinking of using a simple circuit in the battery box to 'chop' the DC - or pulse it. Or, to use AC, which will mean a mains transformer dropping to some low voltage, maybe 9v AC, and getting that out to the boxes at the end of the vege patches to attach to the wires around the patch. This would mean using some easy form of limiting current - cos we really don't want the possibility of things getting dangerous.
The thinking behind using pulsed DC or AC is that there is more chance of slugs being 'bitten' and then deterred (which means I don't have to clean them off the wires), as opposed to DC which bites and doesn't let go. This is one reason that standard stock electric fences are pulsed. You feel the hurt but kinda get kicked away by it, where with DC one could grip it until one dies.
trade4us2,
Sep 15, 8:36pm
That's why you should have the wires on a vertical piece of timber. Then the gastropods fall off!
mark_g,
Sep 15, 8:54pm
Sooby
These aren't great shots. This was when it was put in using 1.2mm galv "tie wire" a year ago.
One shot shows one end of a vege patch and the battery box and two wires quite clearly. The other shots you have to look closely to see the two wires going around the beds. Look for the white corner plastic bits. I used these to stop the slightly tensioned wires cutting into the wood corners. Staples pinning the wires are SS.
This weekend I'll replace the now badly rusted wire with 1.2mm SS (MIG Welding) wire and just get it going using a 9v battery, because I need it going fast.
Once the wire is live, this stops slugs and snails getting into the patch, but I still have to eradicate the majority of slugs & snails that are already in the patch. To do this I use beer traps. Marmite jars, filled maybe 2cm with beer, set half the jar height into the vege patch dirt. About 3 per patch (my patches are about 4.5 x 1.5m each). Eventually, after a week or so, the numbers of slugs floating in the beer traps diminishes rapidly and then you know you're onto a winner.
cleggyboy,
Sep 16, 8:50am
Thanks for the info, I have all the gear ordered as we speak.
mark_g,
Sep 16, 9:51am
Check the pics. It is on the vertical. Many do fall off, but quite a few don't - they stay there getting crispy!
mark_g,
Sep 16, 10:05am
In the 2nd of the 1st four pics I posted you can see the beer traps in the garden. They're under those upended plastic bottles, which are there to stop the rain getting into the beer and watering it down.
I stick 3 little sticks in the ground around the half buried beer jar and plonk the upturned bottom half of a plastic bottle onto the sticks. Arrange the height of the sticks so that there's a 2-4cm gap at the bottom - for the victims to get in, and not too high because you want to stop the rain getting in. If done right the bottles usually stay there in most high winds.
Then have three wires. 1.5 volts between the first two, and 9 volts after that.
jan2242,
Sep 16, 11:10am
Can I ask an off topic question? Love your raised gardens, but do they have a base? I have raised gardens at home and the soil washed away through the pebbles that surround. This caused mega weeds, and of course I am forever topping up the gardens- very costly.
mark_g,
Sep 16, 11:30am
That's a really interesting idea. Simple yet cunning! Pretty easy to do too.
First I'll just get the thing going on 9vdc because I need start reducing the slug numbers now. Then I'll try pulsed DC. If that doesn't reduce the crispies or if it has other disadvantages then I'll try a 3rd wire. It has the big advantage of being simple.
I already have waterproofing issues with the battery box so a few electronic components to chop the DC might not last long, unless I seal the whole component board in a resin or similar.
mark_g,
Sep 16, 11:57am
No base. The wooden box frames are just sitting on dirt, sunk into the original ground level a couple of inches - actually sitting on bits of brick/rock that I used to level them (my section has a slight slope on it).
It's completely normal for organic matter & aerated dirt to sink. So most years I'm topping up the raised beds a couple of inches. I usually grow a cover crop over winter and also mulch in summer so all this organic matter goes down into the soil over time. It makes for seriously good soil. At end of winter I Just stick 1-2 inch layer of compost on top and in spring mulch again over that. Can choose to garden "no dig" style, or not.
Wind blown dust, dirt, leaf matter etc. will settle in the stones surrounding the garden and start looking like good dirt. Can't avoid it. Also if you dig your raised gardens or are wheel barrowing dirt/compost in then you can't help get dirt on the ground. Wind blown or bird deposited seeds will eventually grow in this dirt in your stones. The driveway chip I used around those beds is reasonably deep and I find it pretty easy to either pull the odd weed out of the stones or just rake the stones over and this pulls/kills/buries the weeds and cleans things up nicely.
jan2242,
Sep 16, 1:59pm
Thanks. I might try a winter crop and see if that helps. Mine is L shaped and takes c15 bags every Summer. I am certain the builder has in low int he ground so no idea why the soil washes out. I am careful to pick up leaves etc so am a little stumped. Never mind, it's better than nothing. Thank for your help
sooby,
Sep 17, 8:46pm
Cheers Mark - appreciate the photos.
Would have thought with the frost cloth over preventing flying insects & your electric fence for crawlies you are onto a winner keeping veges pest free.
Thanks for another good idea to add to my to-do list
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