wood ash to fight slugs

richdelmoFebruary 25, 2007

I recall a recent suggestion to use fireplace wood ash in garden paths as a slug combatant. Based on outdoor elements I was curious how long it is effective and when it should be re-applied. Thinking about this it makes sense that after a good rainfall the ashes would depleted, or do they maintain themselves despite the washout.

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jean001(z8aPortland, OR)

Must remain dry.

Beyond that, the question is whether your soil will benefit or be damaged by the wood ash.

    Bookmark   February 25, 2007 at 2:59PM
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Wood ash, when wet, will become lye a very caustic substance and the minerals in that wood ash will go into your soil and may, temporarily, change your soils pH and cause growth problems in your plants.
A better method of detering slugs is to spray your plants with cold, caffienated coffee.

    Bookmark   February 26, 2007 at 6:50AM
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kqcrna(z6 SW Oh)

Can anyone tell me at what soil temperature slugs become active? I want to get out in spring and fling some Sluggo into my planting beds asap before planting flowers, but I don't want to waste it.

I hope to have many wintersown seedlings which I'll plant out very early, like at the 2 true leaf stage. Those !#^*! slugs tend to treat such tiny seedlings as a smorgasboard just for them.


    Bookmark   February 26, 2007 at 7:34AM
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kimma, what does the cold coffee do to keep slugs away, and how often does it need to be re-applied.

    Bookmark   February 26, 2007 at 9:54AM
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Ashes turn to lye and thus becomes caustic?

Oh dear, and I just spread some ashes under my tires to get me out of a snowpile. Does that mean my tires are going to deteriorate from such causticity.
And I spread ashes around my clematises and iris and peony in the spring. Have I done them in?

I've heard of caustic soda....or lye and know it has particular properties:

Specific foods processed with lye include:

The Scandinavian delicacy known as lutefisk (from lutfisk, "lye fish").
Hominy is dried maize (corn) kernels reconstituted by soaking in lye-water. These expand considerably in size and may be further processed by cooking in hot oil and salting to form corn nuts. Nixtamal is similar, but uses calcium hydroxide instead of sodium hydroxide.
Hominy is also known in some areas of the Southeastern United States, as the breakfast food grits, dried and ground into a coarse powder. They are prepared by boiling in water, with the addition of butter and other ingredient to suit the tastes of the preparer.

Sodium hydroxide (lye)...(caustic soda) is also the chemical that causes gelling of egg whites in the production of Century eggs.
German pretzels are poached in a boiling sodium hydroxide solution before baking, which contributes to their unique crust.

Seems the lawn is wasting a good product that can be better used in the kitchen.

Kimm, we're talking a little residue from burning wood...and if one wishes to read about the specifics of wood ashes, one will see it has goodness in its use in the garden.

    Bookmark   February 26, 2007 at 8:36PM
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Jeannie7, your lack of knowledge is totally amazing. Most of us have known for many years that running water through wood ash would produce lye, I even remember my grandmother doing that to make soap. Check the link below to learn about lye.

Rich, a few years back on the island of Hilo some USDA researchers found that spraying cold caffienated coffee on plants detered slugs. Shortly after reading that I put the wee bit of leftover morning coffee in a spray bottle and went out and sprayed some slugs and watched them writhe and wriggle and (for them) rapidly leave that area. For several weeks no slugs reappeared, but like many other things you would need to reapply that each time it was washed off the leaves, ie. after a rain or after you hosed the plant down.

Here is a link that might be useful: Lye

    Bookmark   February 27, 2007 at 7:59AM
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I've used the wood ashes, but it was a no-go. Had to be reapplied after raining and sometimes they simply ignore it. No detrimental effect on the plants in the area.

I have had some success with spraying a very - note VERY - strong brew of coffee on hostas. It's the caffeine which they don't like and if they are sprayed directly it supposedly acts as a neurotoxin and kills them. Posted a link which might help. At the bottom, they discuss this coffee thing.

One thing I've done which has also helped is after the ground has thawed I've watered the gardens with a solution of 1 part amonia/ 10 parts (or more) water. Amonia kills slugs and their eggs and if you can get their eggs you're ahead of the game. Amonia = Nitrogen.

Not sure if you live close to the ocean but I also use seaweed as a mulch. The small amount of salt on the seaweed will kill them and when it dries they don't like to travel on it because it's sharp.

Best of luck in this ongoing gardeners battle!

Here is a link that might be useful: Anti-Slug Stuff.

    Bookmark   February 27, 2007 at 9:45AM
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I've had excellent results with diatomaceous earth to kill slugs. I use it at the first sign of slug damage (soil surface should be moderately dry) and then a couple of weeks later to get the new hatchlings. I've seldom had to use it any more during the season. Be sure it's the type for garden use, not for pools.

    Bookmark   February 27, 2007 at 1:49PM
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kqcrna(z6 SW Oh)

tiffy: I know that ammonia is nitrogen, but it stinks to hell and back. Hard to believe that it could be beneficial! Is it detrimental in any way to plants or soil life? Will it burn if splashed onto existing plants? How often do you use it?


    Bookmark   February 27, 2007 at 2:48PM
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Kimm, you take a line from a reference to a subject and from it decide that speaks for the whole.

Yes soap is made using caustic soda...with chemicals.
Yes lye comes from such material as wood ash....but not simply by running water through it.

Wood ashes are commonly spread on ice to give traction.
Wood ashes are commonly placed into and around the garden to do in the grubs, the slugs and snails and to give a slight alkalinity to the soil there.

Spreading wood ashes is commonly given in lieu of lime and to suggest such use will harm the grass/soil due to its changing its chemical composition is bunk....pure bunk.

I invite you to read the article on wood ashes, let your eyes be your guide. I'll speak no more on the subject

    Bookmark   February 27, 2007 at 4:02PM
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buffburd(z5 NY)

Or, if you have too many slugs and snails, you could encourage snakes, frogs and toads to move into your garden, and eat them up.

Frogs and toads (and I would expect snakes) like to have a source of water and a covered area that will keep cool and moist. So you could add small shallow containers of water, or a pond feature along with half buried terra-cotta pots around the garden, as little frog-houses. Perhaps a log or two, artfully arranged, for another place for little slug eating critters to nap.

    Bookmark   February 27, 2007 at 7:07PM
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I apply only once a year in the spring as soon as I see the nibs of the hostas breaking ground. I've seen a major decline in slug population since I've been doing this compared to the years I didn't.

The smell isn't that strong and dissipates quite quickly. The dilution also helps. I should also add that sometimes my compost stinks to high heaven too but after a while it turns out to be pretty good stuff. :)

No bad effect on the nibs of the hostas that I've seen and all the Astilbes, Columbines, Eupatoriums, etc do fine as well although at that time some have yet to break ground. If some have - sometimes the Columbines are up - I just pour it around the plant and not on it.

    Bookmark   February 28, 2007 at 7:52AM
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kqcrna(z6 SW Oh)

Thanks, Tiffy. Maybe I'll try that this year. It sure would be a lot cheaper than all that Sluggo.


    Bookmark   February 28, 2007 at 10:03PM
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led_zep_rules(5 WI)

Hello, this is a repost from last fall: I can't believe that no one has mentioned beer! I have in the past used shallow tin cans (like tuna or cat food comes in) with the lid partly attached, so that the top of the can is flush with the soil. Fill can with beer. Slugs will rush in to a happy death.

My brother gave me some Slug Saloons, little green jobs with slightly elevated caps (to keep out rain.) I hadn't used them before because I haven't had slug problems for years (good organic soil!) Then this year was wet wet wet and they came out in force, especially attacking my wax beans. I put out the Slug Saloons, they quickly became filled with dead slugs. Disgusting, but easy, cheap, and organic. And if there is extra beer left you can drink it. :-) It is important to have the container only slightly open, so that slugs can crawl in, but not larger things. I found a drowned toad in the beer once years ago, felt dreadful about it. If you don't have any beer (you poor thing!) or don't want to share it with slugs, you can just mix a little yeast and sugar in some water, they like that, too.


    Bookmark   March 2, 2007 at 3:29AM
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I tried the beer and it does work. But then the dogs discovered they love beer and at night the racoons think I've set up a bar for them...

    Bookmark   March 2, 2007 at 5:53PM
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led_zep_rules(5 WI)

Ah, that is where the Slug Saloons come in handy vs. a tin can with cover partly attached. The Slug Saloon roof fits pretty tightly, in fact it is hard to pull them apart sometimes, so that would keep your dogs out. The covers extend over the side so animals can't drink out of them at all. Racoons are a little more dextrous but would probably spill the things before they got at any beer, so at least you wouldn't have drunk racoons in your yard . . . Although that might be a funny sight.

I am sure you could find Slug Saloons for sale someplace, I think the company name is printed on the bottom if anybody wants me to go and look for mine in the basement. I don't usually buy gardening things, I like FREE, but these have been so great I actually recommend buying them. My brother's wife doesn't let him garden or compost, so I get all his gardening stuff. Lucky me.


    Bookmark   March 3, 2007 at 2:43AM
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brdldystlu(5b Mo)

question for you all that use beer traps, I am going to do more with them this year. Can I just throw the sludge into my compost? I know beer would be ok, and think the slugs would not hurt anything. I am temped to just use my sons empty water bottles, make slits in the sides big enough for the slugs to get inside, leave the cap on them, and just replace them as needed. I was thinking of just throwing them away, but hate to waste any good OM.

    Bookmark   March 3, 2007 at 7:03AM
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Jeannie, I have supplied you with this link before about wood ash and Ms. Lerner does a good job of explaining what it does in the soil, and if only a reasonable attempt at reading it is done you will see that she says to not add wood ash without a soil test.

Here is a link that might be useful: Wood Ash in the Garden

    Bookmark   March 3, 2007 at 7:10AM
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tomatobob_va7(z7 VA)

I regularly use small quantities of wood ash to deter slugs.
I apply it lightly, as a dust. Keep the ashes in a waterproof container. Scoop out a juice can full of ashes on a windless morning, and sprinkle a little around lettuce plants, lightly. I've also used ashes (as a dust) on strawberry beds, before the berries ripen. I also use them as a border on the lawn surrounding a bed.
The key here is "light use." Avoid the "if a little is good, more would be better" attitude.
An excerpt from kimmsr's cited article is worth a close look. Don't use your garden as a way to dispose of your wood ashes, but:
"Applying small amounts of wood ash to most soils will not adversely affect your garden crops, and the ash does help replenish some nutrients. But because wood ash increases soil pH, adding large amounts can do more harm than good. Keep in mind that wood ash that has been exposed to the weather, particularly rainfall, has lost a lot of its potency, including nutrients."

"Crop tolerance to alkaline soil also should be considered. Some plants, such as asparagus and juniper, are more tolerant of slightly alkaline conditions than "acid-loving" plants, such as potatoes, rhododendrons and blueberries. Wood ash should never be used on acid-loving plants."

    Bookmark   March 5, 2007 at 11:31AM
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franktank232(z5 WI)

IMO, i wouldn't hesitate throwing wood ashes in the garden. Not sure if they'll fight slugs, but doubt if you spread it around, that wood ashes would really do much to harm your soil. I'm going to have a 5 gallon pail worth of wood ashes and i plan on sprinkling them on my lawn.

    Bookmark   March 6, 2007 at 12:01PM
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bean_counter_z4(Zone 4, Rkfd,IL)

Kimmsr's link suggests the use of 20-pounds of wood ash on a 10 X 10 area may change the soil PH. I don't think Jeannie is talking about nearly that much--just a surface sprinkle, right? Soil PH is not easy to change and only temporary at best. Even repeated applications at say 5-pounds (or less) per 100-sq ft would not change the PH. 20-pounds would be a lot of ash.

    Bookmark   March 23, 2007 at 10:12AM
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