After spraying weeds and grass with paraquat - how long is it
before one notices whether it has worked? And what happens to
the plants? Do they turn yellow first? My plants don't look any
different to how they did 2 days ago when they were sprayed.

On Mon, 06 Mar 2006 14:50:26 GMT, Jasbird wrote:

... After spraying weeds and grass with paraquat - how long is it
... before one notices whether it has worked? And what happens to
... the plants? Do they turn yellow first? My plants don't look any
... different to how they did 2 days ago when they were sprayed.

What sort of ground temperatures have you?
If it is working, four days should see a difference

Mike P

Jasbird wrote:

After spraying weeds and grass with paraquat - how long is it
before one notices whether it has worked? And what happens to
the plants? Do they turn yellow first? My plants don't look any
different to how they did 2 days ago when they were sprayed.

They are probably ice cold and barely metabolising. Paraquat and most
other weedkillers only take effect when plants are in active growth.

If I tried spraying my plants now it would freeze on contact - the soil
is like concrete.

You might see something happen eventually when it warms up a bit and
growth restarts but the active ingredients will lose some potency in the
meantime. Using weedkiller during cold snaps or immediately before heavy
rain is wasteful! The instructions should advise minimum temperature for
effective use.

Regards,
Martin Brown

wrote in message
ups.com...
Depends where you are, assuming the UK it will take quite a while at
this time of the year. It is much more effective when plants are
growing strongly. Toips will turn yellow, and then start to die, the
die back will move down the plant till it all dies. Paraquat is
systemic and kills the roots as well as the tops. Much better to
spray
when it is a little warmer and plants are really beginning to grow.

Paraquat is *not* systemic - it kills top growth only, that's
sufficient to see off annual weeds but perennials will regrow.
It is still a bit early for using Paraquat - it does need some foliage
to work on. Results are seen more quickly in sunny weather. A few
hours for first signs and a day or two for obvious damage if used in
good conditions.
I haven't used Paraquat for many years - there are much safer and more
effective materials available - Glyphosate is the active ingredient
to look out for as in the various incarnations of 'Roundup' That *is*
systemic and will see off perennial weeds. (Particularly good against
perennial grasses and stinging nettles) Works more slowly than
paraquat.


--
Rod

My real address is rodtheweedygardeneratmyweedyisp
Just remove the weedy bits
and transplant the appropriate symbol at.

On Mon, 6 Mar 2006 18:17:37 -0000, "Rod Craddock"
wrote:

wrote in message
oups.com...
Depends where you are, assuming the UK it will take quite a while at
this time of the year. It is much more effective when plants are
growing strongly. Toips will turn yellow, and then start to die, the
die back will move down the plant till it all dies. Paraquat is
systemic and kills the roots as well as the tops. Much better to
spray
when it is a little warmer and plants are really beginning to grow.

Paraquat is *not* systemic - it kills top growth only, that's
sufficient to see off annual weeds but perennials will regrow.
It is still a bit early for using Paraquat - it does need some foliage
to work on. Results are seen more quickly in sunny weather. A few
hours for first signs and a day or two for obvious damage if used in
good conditions.

It will be illegal soon - so I'm told. New EU regulations were
passed last year and I think they come into force in the UK next
month. I got my week-killer cheap at B&Q when they were selling
it off.

I haven't used Paraquat for many years - there are much safer and more
effective materials available - Glyphosate is the active ingredient
to look out for as in the various incarnations of 'Roundup' That *is*
systemic and will see off perennial weeds. (Particularly good against
perennial grasses and stinging nettles) Works more slowly than
paraquat.

Unless Glyphosate can be used in this kind of weather it is no
good to me.

I want to kill off my weeds before I dig the ground over because
I don't like having to hoe tough weeds with deep roots (which
have a tendency to re-grow even when dug over - especially couch
grass.

The ground is being dug over so I can plant my veges - I've
never used weed killer before.

Paraquat has arsenic in it and it can sterilize the soil it is used
for clearing lanes and sidewalks.

Derryl Killan
Calgary, Alberta, Canada.


Most weedkillers are ineffective in the kind of weather you have in the
UK at the moment. they all need active growth of the weeds to work.
Glyphosphate will kill down to the roots, but wiill only work very
slowly, and lose its effectiveness in the cold weather. Weedkiler
containers usually state to use when weeds are in active growth, and
usually state in Spring and not if it is likely to rain as they only
become effective once they ahve been absorbed by the weed. The
advantage of glyphosphate is the once the weeds have been killed it is
safe to plant seeds and plants as it is not retained in an active form
in the soil.

"Derryl" wrote in message
...

Paraquat has arsenic in it and it can sterilize the soil it is used
for clearing lanes and sidewalks.

Derryl Killan
Calgary, Alberta, Canada.

Unless they have changed the formulation for Canada then it does not and
never has contained Arsenic.
FWIW Paraquat=1,1'-dimethyl-4,4'-bipyridylium dichloride)

Derryl wrote:

Paraquat has arsenic in it and it can sterilize the soil it is used
for clearing lanes and sidewalks.

This is complete and utter ********. Paraquat is a fast acting knock
down contact weedkiller of the bipyridine family. It is most notable for
the tendency of would be suicides to drink it (a horrible way to go).

There are far better formulations like "Pathclear" for clearing paths
that include a long acting pre-emergent herbicide like Simazine.

Paraquat binds strongly to clays and is inactive by physical adsorbption
on most soils. I cannot offhand think of any modern herbicide that
contains arsenic. Glyphosate is usually preferable on toxicity grounds
though especially if you have small children or pets.

Most weedkillers are ineffective in the kind of weather you have in the
UK at the moment. they all need active growth of the weeds to work.

The thing it demonstrates ever so clearly is that the average user
cannot be trusted to RTFM with potentially dangerous garden chemicals.

Regards,
Martin Brown

Jasbird writes
Unless Glyphosate can be used in this kind of weather it is no good to
me.

I want to kill off my weeds before I dig the ground over because I
don't like having to hoe tough weeds with deep roots (which have a
tendency to re-grow even when dug over - especially couch grass.

I'm not sure anything is going to be much good to you then ;-)
A weedkiller which works on the active growth is not going to be of use
at the moment, and anything which prevents re-growth will have adverse
effects on your veg.

What have you done in previous years? - hand-picked the couch roots as
you dig?
--
Kay

"Martin Brown" wrote in message
...
Derryl wrote:

Paraquat has arsenic in it and it can sterilize the soil it is used
for clearing lanes and sidewalks.

This is complete and utter ********. Paraquat is a fast acting knock down
contact weedkiller of the bipyridine family. It is most notable for the
tendency of would be suicides to drink it (a horrible way to go).

There are far better formulations like "Pathclear" for clearing paths that
include a long acting pre-emergent herbicide like Simazine.


I think that simazine has now been removed from the formulation
snip

The thing it demonstrates ever so clearly is that the average user cannot
be trusted to RTFM with potentially dangerous garden chemicals.

Even when folks do read the instructions they still get it wrong. Thank God
a majority of the lethal garden formulations have been removed from the
hands of idiots.
Regards,
Martin Brown

"Martin Brown" wrote in message
...
Jasbird wrote:

After spraying weeds and grass with paraquat - how long is it
before one notices whether it has worked? And what happens to
the plants? Do they turn yellow first? My plants don't look any
different to how they did 2 days ago when they were sprayed.

They are probably ice cold and barely metabolising. Paraquat and most
other weedkillers only take effect when plants are in active growth.

If I tried spraying my plants now it would freeze on contact - the soil is
like concrete.

You might see something happen eventually when it warms up a bit and
growth restarts but the active ingredients will lose some potency in the
meantime. Using weedkiller during cold snaps or immediately before heavy
rain is wasteful! The instructions should advise minimum temperature for
effective use.

Regards,
Martin Brown

************
Do not meddle with paraquat and don't have bottles sitting on a shelf in
your shed or anywhere else..
It attacks the plant systems with very effective surety.
Even a small amount introduced into the human system is serious and there is
no known antidote. You'll die just as surely as the plants.
Doug.
YHBW
************
Doug.

On Tue, 7 Mar 2006 18:03:03 +0000, K
wrote:

Jasbird writes
Unless Glyphosate can be used in this kind of weather it is no good to
me.

I want to kill off my weeds before I dig the ground over because I
don't like having to hoe tough weeds with deep roots (which have a
tendency to re-grow even when dug over - especially couch grass.

I'm not sure anything is going to be much good to you then ;-)
A weedkiller which works on the active growth is not going to be of use
at the moment, and anything which prevents re-growth will have adverse
effects on your veg.

The weed killer was fairly effective. Not perfect but 90% OK.

What have you done in previous years? - hand-picked the couch roots as
you dig?

More or less.