Tag Archives: glyphosate

The glyphosate debate

The visual and environmental scourge of the scorched earth roadside

Glyphosate has been much in the news of late and the calls to ban it are increasing in this country. I am no scientist so any opinions we have here are based on experience and observation. Because we ran a plant nursery for about three decades, our experience with sprays is greater than the average home gardener. You don’t think all those brilliant looking plants you buy from the garden centre are grown organically, do you?

Because of my lack of scientific background, I was pleased to find a post on the credible and independent Sciblogs site, written by scientist, Dr Grant Jacobs. If you have any interest in the use of glyphosate, I would urge you to read it in full here.

If you are not going to read it in full, the key points I have taken from it are:

  • The original probable (not definitive) link between glyphosate and cancer was made by IARC in 2015 (IARC being the International Agency for Research into Cancer which comes under the World Health Organisation). IARC’s role is to flag areas for further investigation and identify hazards, not to make definitive rulings. Even the term ‘probable link’ is an oversimplification of IARC’s findings.
  • The role of risk assessment on those potential hazards falls to regulatory bodies – the Environmental Protection Agency is a key body in NZ. And while IARC made the initial finding, subsequent investigations by scientists in such regulatory bodies around the world have not raised red flags. It appears that all such investigations have cleared it as safe when used according to instructions and with usual safety precautions. The difference between hazard and proven risk is important.
  • Any blanket ban on such a product comes down to a political decision and that is what we are seeing happening in Europe. A political decision is not necessarily based on science. It can often be based more in public opinion and political polling.
  • The court case in USA which triggered the recent round of debate (the school caretaker who contracted cancer) is based on a judge and jury trial in a courtroom and as such it is subject to the vagaries of a court system where the jury may or may not understand the science and where the directions given by the judge have a huge influence. This will all be tested further in the appeals process but a court case does not constitute rigorous scientific enquiry and risk assessment. While the case is certainly interesting, it is not proof of anything at this stage.

Jacobs also clarifies why we need to be talking ‘glyphosate’, not using the original brand name of Round Up. Indeed Round Up for Lawns contains no glyphosate at all. It is the chemical that is under scrutiny, not the branding. Round Up is a Monsanto product and while there are many concerns about Monsanto across a whole range of issues, the safety or otherwise of glyphosate should not be confused with a battle against Monsanto business ethics (or perceived lack thereof). Let us keep the arguments separate.

I was listening to a discussion on Radio NZ about all this and the host went on and on about the safety of glyphosate. “Is it safe? Can you guarantee it is safe?” he kept asking. Wrong question. How safe is it if used properly? Is the risk within acceptable limits? These might be better questions. Our lives are filled with hazards that we choose to manage. In the 44 years that glyphosate has been in use, it has proven itself to be safer than many other chemical sprays that are, or were, also used. Remember Paraquat? I don’t think there is any dispute that glyphosate is hugely safer than Paraquat but is it safe enough to continue using?

I worry about the nature of public debate that may see political decisions to ban what has so far been a relatively safe agrichemical, while leaving far more dangerous options on the market. Unless we have a change of heart, mind and practice on how we manage weeds and pasture, we run the risk of banning one option, only to have people substitute with another spray that could be way worse. We are a country that accepts a pretty high level of use of chemicals, toxins and sprays. While some are now controlled and you need to be an approved handler to buy them, the home gardener can still buy a fair number of products across the counter that are no longer available to their counterparts in the European Community.

The issue of the possible threat to human health underpins all this debate with IARC, cancer and banning glyphosate. It is separate to the issue of the impact on ecological systems. That is a whole different area to be considered. There are theories that environmental damage may be more to do with the surfactant (the sticking agent) rather than the glyphosate. We have also raised our eyebrows at the quick knockdown glyphosate products – the convenient aerosol or pump sprays that the home gardener can use to kill a plant more or less instantly. But again, that is a separate issue to fundamental matter of the claimed threat to human health.

It is complicated, not black and white. By all means, go organic and shun the use of non-organic sprays in your own garden. But maybe don’t cast glyphosate as the greatest villain of all the sprays and single it out for blanket bans while leaving the others on the market. I think that is called throwing the baby out with the bathwater.

Time will tell if we will face a future without glyphosate and that bears some thinking about for home gardeners, farmers and most landowners as well as the public sector which maintains the parks, reserves, road verges and playing fields. Our attitudes to weeds, to invasive plants, to long grass and to presentation standards which are widely held as desirable will have to change too. On the bright side, the scourge of the scorched earth roadside may disappear which would be hugely beneficial both environmentally and aesthetically, in my opinion at least.

My new weeding friend

The weed growth in this new area under development was scary after a few weeks of spring

I have a new weeding implement and a very good one it is too. Meet my little Wolf-Garten Multi-Star Cultivator Weeder LBM (I wrote the full name down from an internet search). It is my new best friend.

Having been away to Australia, then coming home somewhat unwell followed by other demands on my time, the weeds in my newly planted borders were threatening to get away on me. With my trusty weeding armoury, I made short work of quite large areas. It was the little cultivator on the long handle that covered the area quickly and efficiently. Unlike a hoe, it does not cut the plant off and being very narrow, it can get in close to plants without damage. It is only 7cm at its widest point.

My new Wolf-Garten cultivator, the modest Wonder Weeder and my short handled hoeing implement deal to most weeding situations

One weeding tool does not suit all situations. This cultivator makes short work of scuffing up the surface and dislodging the weeds where soil is friable or there is mulch. It is no good on compacted soil. It also needs to be used before the weeds have set seed and is best on a sunny day so the dislodged weeds shrivel and dry in the sun. As long as they haven’t reached the seeding stage, the weeds do not need to be removed. It is so easy to use, saving bending and stretching, that weeding is not something to dread. A quick follow-up the next day despatched the few weeds that had escaped the first round. If you have similar conditions, buy one is my advice.

Where the plants are closer together (these were newly planted areas that I was speeding around with my cultivator), I resort to the hooked wires known in this country as Wonder Weeders (cheap as chips at under $5 when I bought another three at the garden centre last week). In the case of compacted ground with club moss, liverwort or clover, I use the short-handled implement that looks like a small Dutch hoe. You can get long handled versions of the Dutch hoe to avoid having to bend or kneel, but I am fine with the precision of my short version.


The new baby cultivator and its full-sized companion on the left and the trusty old Planet Junior to the right

Mark is a push hoe man (the Dutch hoe is pulled towards the user whereas the push hoe is pushed away from the user) but it takes some skill to be a reliable operator and it is all too easy to accidentally sever desirable plants from their roots.  Where there is more space to move, such as in his vegetable patches (known here as Mark’s allotment), he will reach for his trusty old Planet Junior that makes quick work of surface cultivation or the big granddaddy cultivator relative of my new, small version.

What about weed sprays? Mark follows the international debate and research on glyphosate (the active ingredient of Round Up) with reasonably keen interest. When Round Up hit the outdoor maintenance world in 1974, it was seen as saving the equivalent of a labour unit and it changed attitudes to weeds in the garden. Being seen to be weed-free became mandatory for “good” gardening. Mark has used a fair amount of it over the years to maintain our gardens and wider property. With the huge volume of glyphosate that has been used throughout the world over 43 years, if it was the worst thing since Paraquat, DDT and the likes, we would expect there to be more compelling evidence but it is not an open and shut case. That said, caution is always advisable and I worry about its use as a desiccant on commercial food crops.  Certainly, Mark has hugely reduced how much he uses it, which has seen us returning to some older, tried and true methods of cultivation.

I would comment that with the amount of conflicting evidence on the safety of glyphosate, we are a little concerned about what is mixed with it to give the near instant knockdown capabilities of the over the counter, ready to use spray dispensers that are widely sold. Glyphosate used to take up to three weeks in cooler weather to kill weeds and there are various plants that are resistant to it. Those ready-mixed spray cans can kill within hours. When I used to write for the newspapers, I was sent samples of two different such sprays called “Weed Weapon” with ‘breakthrough technology’. I rarely use them but they are both scarily easy to use and efficient at killing plants, even ones that I would not expect them to knock out. The combined effects of glyphosate and saflufenacil are much greater than glyphosate alone.

Compacted soil, the result of years of no surface cultivation and likely use of weed spraying for maintenance – not our garden.

In terms of garden maintenance, repeated use of weed sprays as routine control leads to soil compaction and the growth of liverwort which we find unsightly. We are guilty of judging open gardens on their visible use of weed sprays for maintenance. But then we are subscribers to the school of soil cultivation and mulching when it comes to gardening.

With the growing antipathy to chemical controls for weeds, we may need to revise the aesthetic value placed on weed-free gardens. Even my new-found cultivator friend has its limitations. But weeding a little often is probably the best way to go for most keen gardeners.




The Terminator of the World of Weeds?

A free sample for review! The terminator of the weed world.

A free sample for review! The terminator of the weed world.

It is not in the job description for garden writers that freebies are included. In all my years of garden writing, excluding books for review, I could count such things on the fingers of one hand. I only mention this because I once found out that the wine writer for a provincial newspaper received boxes of samples to his door. I was so jealous.

Imagine my excitement when something arrived. Even more excitable was the accompanying publicity sheet which proclaimed “hasta la vista” to weeds when using (wait for the drum roll) Weed Weapon. Yes folks, I had a convenient spray bottle of weed killer in my hands.

First up, let us be clear. Despite the name of the company that produces this product being Kiwicare, which sounds so wholesome, there is nothing organic about it. It is a new twist on an old standby which is glyphosate (formerly sold only as RoundUp). Forty years of experience tell us that of all the herbicides around, glyphosate is as close to safe as you can get. It could be argued that it has revolutionised the way we think about gardening and lowered our tolerance for weeds. Glyphosate has often been described as the equivalent of a labour unit because you can whip around with a knapsack on your back and cover a large area very quickly.

We use glyphosate here and Mark has always dreaded the day that it may be found dangerous because we could not maintain the standard we want in our garden without it. He has kept an eye on the research and there is no hard evidence that it is damaging or dangerous. This is because it does not accumulate and it breaks down very rapidly on contact with soil or water. It does not cause cancers, it does not appear to harm insect life and basically you would have to swallow a fair amount of it undiluted to cause yourself any harm.

It was a very different story with earlier weed killers. Paraquat was and still is used in some quarters as an alternative to glyphosate. It knocks down plants within hours of application and its environmental bill of health is not too bad. It is also the main tool with which to commit suicide in third world countries because it is cheap, readily available, has no antidote and you need very little in order to cause a deeply unpleasant death. Its dermal toxicity (in other words the ability to be absorbed through the skin) is very high which makes it dangerous for gung-ho home gardeners.

Back to Weed Weapon, which gives the quick hit of Paraquat, apparently without the dangers. One of the problems with glyphosate is that it takes a long time to be sucked into the plant’s system and to kill it. This is temperature related so it can be about seven days in summer and anything up to three weeks in the depths of winter. In that time, some weeds have the capacity to set viable seed. Weed Weapon’s active ingredient remains glyphosate, at 7.2 grams per litre. As far as I can see from Monsanto’s website, this is at the weaker end of dilution rates best suited to quick growing annual weeds and grasses. What makes the difference is the combination with saflufenacil which is a recent addition to the weedkiller range. It is this that gives the knockdown, browning effect on weed leaves within hours. I did a bit of a search on this saflufenacil but the papers Google pulled up were all highly technical and well beyond my very limited high school science. The publicity from Kiwicare blinded me further with science (Protoporphyrinogen Oxidase inhibitor) but it will have been approved for sale by the appropriate New Zealand authorities. It is claimed that it is biodegradable in soil. I mention this because we know glyphosate is but sometimes, when different chemicals are combined, the result can be less predictable than just the sum of the parts.

At least the pesky equisetum is dying

At least the pesky equisetum is dying

What I can tell you is that Weed Weapon in its ready to use form is perhaps worryingly easy to use. It comes in a squirty bottle like window cleaner. It requires an accurate aim because if you catch other plants, you may kill them too. It certainly knocks down most plants quickly – the dying process is visible within hours. You will be paying for convenience. It retails for around $20 for a one litre squirt bottle. For me, its most useful application is killing out a nasty, invasive equisetum which wriggles out between rock walls but resists being pulled out with its roots. Paraquat users would be well advised to swap to this safer option.

If you are going to use it, you should always wear gloves and not just gardening gloves as shown on the little pic on the back of the pack. Most gardening gloves are absorbent to some degree. You should be using rubber, plastic or latex gloves which you can buy at the supermarket. While it may well be relatively safe to use with low dermal toxicity, good practice says to take precautions. Wearing impermeable gloves is one and never spraying on a windy day is another.

First published in the Waikato Times and reprinted here with their permission.

Weeding – just like outdoor vaccum cleaning, really

Edging tools, push hoes and our well-used petrol powered line trimmer

Edging tools, push hoes and our well-used petrol powered line trimmer

Weeding. It’s the garden equivalent of vacuuming really. Tedious, repetitive and while the place looks great when you have finished, all too soon you need to start again. I guess you could ignore the weeding part (if not the vacuuming) but most of us prefer a garden that is pretty much free of weeds. In fact most of us place a high priority on this state.

There is a much higher tolerance for weeds in some other gardening countries, particularly in Britain. This may well have something to do with the fact that the vast majority of our weeds in this country are imports and a fair number are in fact native to Britain and Europe – plants like dandelion and blackberry, for example. We are probably more tolerant of our self seeding native plants too. I don’t refer to the scores of nikau palms we pull out and dig out as weeds. They are merely self seeded plants in the wrong place whereas the buttercup and campanulata cherry seedlings are indubitably weeds.

I have to admit we weed spray here though Mark is trying to reduce the amount he does. Glyphosate is pretty much all that stands between us and claiming organic status, but in a large garden, glyphosate is oft described as the equivalent of a labour unit. It is much faster to whip around with the knapsack sprayer than to hand weed. Mark has spent the last decade gently worrying that research will come up with definitive arguments against the use of glyphosate. It hasn’t happened yet, to his relief. But in this day of heightened sensibilities, he is rarely to be spotted by any garden visitor with the knapsack on his back. He hides, dear Reader. True.

The rusted Niwashi, implement for flat weeds and aptly branded Wonder Weeder

The rusted Niwashi, implement for flat weeds and aptly branded Wonder Weeder

We have a repertoire of weeding implements here and do a fair amount of hand weeding too. Others swear by the Niwashi weeder, to the extent that Mark bought one and it was relatively expensive as I recall. I asked him this week if he had ever used it because I never have. Neither has he, apparently, but somebody here must have because it made the trip right through the compost heaps emerging after about a year at the other end. Mark is a push hoe man and keeps his favourite two well sharpened. However push hoes come with a warning – refer to the quote of the day below! I have heard of one public garden which banned push hoes in the hands of volunteers because they caused so much damage. I favour the precision of close up work with the cheap and cheerful Wonder Weeder – so cheap that I have several and so sturdy that they can emerge from the compost heap pretty much unscathed. These implements work best in loose, friable soil. It is much harder work in compacted earth but a breeze where it is easy to scuff up the surface and hook out or sever weeds.

We also have edging tools – ones designed for both hard edges (where grass meets a solid surface like a path) and soft edges. And let’s not forget the petrol powered line trimmer but that is excessive unless you have a large section. These are because of a strongly held opinion on Mark’s part that little looks worse than sprayed edges. You know that dead brown line others have? Not here. The lawn weeder is also well used since we made the decision not to spray the lawns. Nothing works as well on flat weeds as this handy implement.

The bottom line of weeding is that vigilance and early intervention lessens the task. There is an old saying: “one year’s seeding, seven year’s weeding”. You can never completely eliminate weeding but if you can stop seeding, you certainly lessen the load considerably. We are lucky in that we took over this garden from Mark’s father who was a vigilant weeder. True, he leaned towards the chemical arsenal to carry this out as so many of that generation did. But at least we don’t have soils jampacked with weed seeds waiting to germinate. Where a patch may have got away from us and set seed heads, we usually have a bucket on hand to receive them. If you cut them off and leave them lying on the ground, the seeds can still ripen and live to germinate another day. For the same reason, gardening clothes with pockets can be handy.

Spitting cress

Spitting cress

Get ‘em when they are small and much easier to deal with. Soon after germinating is the best time, before they have well established root systems. They are far easier to hoick out of the ground and far more likely to die instantly at that tender stage. While the saying that a weed is merely a plant in the wrong place is repeated so often it has become a cliché, I can not think that the nasty spitting cress fits this kind interpretation. Every gardener knows it – the little flat weed which can go from first appearance to setting seed in a matter of days in full summer. As soon as you touch it, it jet propels its seeds around to ensure immortality. Vigilance – that is the single most important mantra. Target the worst offenders and maybe be a bit more relaxed about some of the others.

First published in the Waikato Times and reprinted here with their permission.