Sciencemadness Discussion Board - Plant killer

Plant killer

urenthesage - 19-10-2021 at 12:48

Im looking for a metal salt or complex that can act as a long term biocide for plants and mosses. Any suggestions that arent a long term concern?

B(a)P - 19-10-2021 at 15:05

Sodium chlorate will do the trick.

Fery - 19-10-2021 at 20:49

as B(a)P wrote, NaClO3 is very effective and long lasting
for short term just spray plants with vinegar (not the soil, spray plants, their leaves, in dry days, not before raining)
for getting rid of mosses use FeSO4*7H2O

zed - 20-10-2021 at 00:06

CDX Plywood. Older stock is better. Got any surplus plywood? It isn't a metal salt, but it sure works.

Just lay it down, and forget about it. CDX in soil contact usta last 15 years or so. Want things to grow again?

Just remove the plywood.

The old Italian ladies usta devitalize the soil of their parking strips with Lye. Drano will do.

After treatment, the soil becomes rock hard. A concrete-like moonscape, that can be maintained in sterile

order, by an occasional sweeping.

macckone - 20-10-2021 at 08:30

sodium chlorate is the classic.
most chlorates would work.
copper chlorate might be more effective.
copper sulfate kills roots.

edit:
copper naphthenate

[Edited on 20-10-2021 by macckone]

draculic acid69 - 21-10-2021 at 21:30

Read somewhere recently sugar was used as a weed killer

barbs09 - 22-10-2021 at 00:36

Roundup!!

Fyndium - 22-10-2021 at 02:07

Doesn't ordinary sodium chloride do the trick? Plants hate sodium, anyway.

B(a)P - 22-10-2021 at 02:26

Quote: Originally posted by Fyndium

Doesn't ordinary sodium chloride do the trick? Plants hate sodium, anyway.

You need a lot more sodium chloride than chlorate. If you want a permanent dead patch devoid of vegetation sodium chloride could be a good option.

Fantasma4500 - 22-10-2021 at 03:55

interesting Zed with the NaOH thing
soil contains a lot of aluminium oxide, which is soluble in NaOH
i have thought of using dirt to make cement for a while, and i suppose this might be hint that it could be pretty great idea
might also be doable to use dirt for polishing as aluminium oxide is quite hard, or even for paint removal, with high pressure air or water jet

i recall hearing plants dont like HCl either, it seems anything to skew the pH might work, maybe calcium hydroxide can do too?
or maybe dig down some detcord and have a go with it

Fyndium - 23-10-2021 at 02:28

Quote: Originally posted by B(a)P

You need a lot more sodium chloride than chlorate. If you want a permanent dead patch devoid of vegetation sodium chloride could be a good option.

Since sodium chlorate is completely banned in Europe nowadays and it would cost tons to make a little, meanwhile sodium chloride is available dirt cheap in large bags, I wouldn't mind compensating. Some areas, like gravel yards are places where you don't want any plants, so longer term devoidness would be desirable. It would quickly drain off by rainwater, so likely it needs to be reapplied once or twice a year, perhaps.

[Edited on 23-10-2021 by Fyndium]

phlogiston - 23-10-2021 at 11:49

Considering the high solubility of sodium chlorate, why does it last so long? Wouldn't rain wash it away pretty quickly?

[Edited on 23-10-2021 by phlogiston]

katyushaslab - 23-10-2021 at 13:00

Quote: Originally posted by Fyndium

Producing lots of sodium chlorate from sodium chloride is pretty cheap? Just run some current through it for a few days to a week, keeping it warm, and it will form chlorate.

If you don't care about the product being clean enough for further synthetic use or pyrotechnic use, you don't even have to be particularly careful about current control, electrodes, etc. A couple of graphite welding rods will do the trick just fine.

draculic acid69 - 25-10-2021 at 04:53

Quote: Originally posted by Fyndium

Quote: Originally posted by B(a)P

You need a lot more sodium chloride than chlorate. If you want a permanent dead patch devoid of vegetation sodium chloride could be a good option.

I tried using nacl to kill some seeds and it worked but exactly as pointed out above
it doesn't last as it washes away.weeds are growing back right where the salt was applied a month or two later.

Bedlasky - 25-10-2021 at 05:46

Sodium chlorate is available in a 40 % mixture with NaCl.

katyushaslab - 25-10-2021 at 08:22

Quote: Originally posted by Bedlasky

Sodium chlorate is available in a 40 % mixture with NaCl.

Unfortunately those weedkillers have been outlawed for quite some time in the EU

Fery - 25-10-2021 at 10:42

katyushaslab - as Bedlasky wrote, 39,9% NaClO3 + 60,1 % NaCl is legal
no restriction in selling, see this:
https://www.funchem.cz/www-funchem-cz/eshop/1-1-ANORGANICKE-...
in comparison with pure NaClO3 which is restricted (concentration 40% and more is restricted)
https://www.funchem.cz/www-funchem-cz/eshop/1-1-ANORGANICKE-...
When I was small boy my good grandma sometimes bought a 1 kg can of Travex which was approx 50:50 mixture of NaClO3:NaCl
She also used CaC2 to get rid of rodents digging tunnels in her garden (the active product was phosphine), that was another cool compound for my chemistry experiments. Naphthalene balls into pockets of coats in the wardrobe. Happy childhood.

katyushaslab - 25-10-2021 at 23:06

The argument to relocate to .cz keeps looking more and more compelling every time I look at it! Not an option for the foreseeable though, and the language is bloody hard.

Does that site (funchem) sell to the rest of the EU? Looks super useful.

Fery - 26-10-2021 at 04:29

Hi katyushaslab, funchem is a company in Czech republic but it sells also to the neighboring Slovak republic. They have a bank account also in EUR currency. I was buying from them more than 2 years ago, maybe 3y, or 4... time passes quickly. You can probably sent them an email with your question. The email addresses are available at this page:
https://www.funchem.cz/www-funchem-cz/2-O-NAS
there are these 2 emails:
funchem@funchem.cz
ucetni@funchem.cz
IIRC whenever I sent an email to the first address they always answered only from the second one.

AJKOER - 1-12-2021 at 08:11

OK, while chlorates work here, be aware that they are also the center of law suits for cancer in people as a result of exposure during application (see, for example, https://www.klinespecter.com/roundup-cancer-lawsuits.html?gc... ).

Advice, AVOID. Do use compounds that are more people friendly (meaning possibly don't kill you also in the long run).

Note, copper salts are more people friendly at low concentrations but also highly effective here (and perhaps overly so, capable of killing trees including your neighbors from water runoff).

My advice, make a copper salts in a galvanic reaction with a carbon source, copper metal, sea salt, dilute 3% H2O2 and lemon juice. Jump start the reaction for a few minutes in a microwave. Intense coloration will become apparent for your copper citrate/ascorbate mix.

I would extensively dilute the mixture and cautiously apply to areas where rain induced runoff will not cause a major concern.

Note: Small animals, fish, worms,..., are likely to be impacted (as in killed,...). Also, application of Baking Soda (NaHCO3) could form an insoluble copper carbonate that may mitigate/reduce the toxicity of the copper mixture if deemed necessary.

In summary, in my opinion (noting that I have not actually used it in practice in a garden setting, only for insect control), an inexpensive powerful but mostly people friendly agent that must be applied prudently and an associated possible remedy to mitigate effects. I suspect also that the copper salts can cause the incidental killing of shrubs

[Edited on 1-12-2021 by AJKOER]

Tsjerk - 2-12-2021 at 02:29

You are confusing chlorate with glyphospate.

AJKOER - 2-12-2021 at 03:33

Yes, thanks, the alluded to lawsuit relates to ROUNDUP, as mentioned in this thread, with claimed problematic active and allegedly 'inert' ingredients as well.

Here is a reference more precisely on NaClO3, "Acute renal toxicity of sodium chlorate: Redox imbalance, enhanced DNA damage, metabolic alterations and inhibition of brush border membrane enzymes in rats" at https://pubmed.ncbi.nlm.nih.gov/30144278/ .

Potentially people unfriendly, in my opinion.

My advice remains: avoid exposure.

[Edited on 2-12-2021 by AJKOER]

Sulaiman - 2-12-2021 at 03:42

For large areas I would not want copper salts as they are too long lasting,
and toxic to many lifeforms.
I would not use any heavy metal salts.

For my gravel drive glyphosate works on most weeds, but needs two or three applications per year.
Acids did very little, (except maybe neutralising themselves by dissolving a little gravel

sodium and/or potassium hydroxide really keep the weeds down for a long time, and have a small cumulative effect.

I've been away from my house for over two years now and photos show some weeds have grown in/through the gravel.

to clear an area of weeds I have used black plastic sheets to deprive the soil of water and reduce sunlight.
100% effective and eco-friendly (except that the plastic is not really re-usable)

[Edited on 2-12-2021 by Sulaiman]

AJKOER - 2-12-2021 at 04:01

Quote: Originally posted by Sulaiman

For large areas I would not want copper salts as they are too long lasting,
and toxic to many lifeforms.
I would not use any heavy metal salts.
.....
[Edited on 2-12-2021 by Sulaiman]

NEW RECIPE

Perhaps a long strip of exposed copper wire (or copper coins) placed over the treatment area?

To expedite results, add a mix of vinegar, dilute H2O2 and sea salt together with crushed charcoal onto the copper source.

When issued resolved, as you pull up the wire, add Baking Soda.

This path likely constitutes a slower/moderated transition of copper ions and a targeted treatment to basic copper carbonate upon project completion.

As such. this process may offer more treatment control over, say, a quick administration of a soluble copper salt (which otherwise could be created rapidly in a microwave assisted process with the cited agents).

[Edited on 2-12-2021 by AJKOER]