The days of trying to solve all garden problems with a quick chemical blast are, thank goodness, long since gone. However there are still occasions when something in a bottle can make a huge amount of difference. Which is why I wrote a 'Talking Point' in Gardens Illustrated magazine on the use of RoundupTMa while ago. Only one letter of objection to the magazine so far. Whew!
Here I'd like to revisit the issue, and pull a few skeletons out of the cupboard. To recap – Roundup is an enormous help in weed control in a new garden, especially one in a climate which favours the growth of a limited number of aggressive weedy species, and in dealing with invasive aliens, like Japanese knotweed. Conservation organisations have long recognized its value in vegetation management, and without it the battle against invasive species would be, quite honestly, hopeless.
We live in a world saturated with toxins. Overwhelmingly natural ones, but a poison is a poison is a poison. Plants, including the veg we eat, produce a formidable array of toxins to dissuade animals from eating them. Certain preparation techniques enhances the impact – a cup of coffee apparently contains more carcinogens than an annual average intake of pesticide residues (http://www.ncbi.nlm.nih.gov/pubmed/9677052).
On the subject of bad stuff, I think we need a bit more honesty about the chemicals used by organic producers. I have heard it said that the most frequent source of chemical injury suffered by US farmworkers (many illegal migrants from Latin America) is sulphur, used as a fungicide by organic growers. I couldn't find a recent reference but here is one for a 2001 study which gives some indication of the problem a few years ago: (www.cdph.ca.gov/programs/ohsep/.../migrantfarmworkers.pdf), and oil and sulphur (both ok by US organic standards) are the most widely used (Roundup is no.8). Regulation of dangerous chemicals used by organic producers is much lower than for conventional. Statistics on use are less well kept too.
How do we find sound information on garden and agricultural chemicals? It is actually quite difficult. Scientific papers are hard to follow without specialist knowledge and often do not give any kind of clear result. The use of technical language can also be misinterpreted; the word 'acute' for example means something quite different to its everyday use. There is ample scope for those with an entrenched, ideological, position to misinterprete the language of these scientific papers. On the subject of Roundup/Glyphosate, I do try to keep up with research, and i have not seen anything seriously untoward about it; and it has been quite intensively studied.
The one place not to look for objective information is anything published by the organic movement or environmentalist campaigning groups. It is obvious that the former have a vested interest in scaring us; this is business after all and they want to increase their market share (currently declining here in the UK); and it is a sad fact for those of who care about environmental issues that many campaigning organizations have a history of putting the campaign first and objectivity and accuracy last – the myth of the 'terminator GM gene' being a good example. At the end of the day, regulation is science-led; newspaper and campaign group literature very often isn't.
As a final shot, here's a very good, and balanced, non-rhetorical sceptical piece on organic farming from Scientific American.
This is what I originally wrote for Gardens Illustrated:
Weed control in the garden can take up a huge amount of time, particularly in mild climates when creeping buttercup and many grasses can grow 365 days of the year. Correctly used, Roundup ™ is a very effective tool for dealing with weeds, especially when creating new areas for planting, when total clearance of existing vegetation is vital, and for large gardens with a persistent weed problem. The beauty of Roundup, perhaps the most successful crop protection chemical ever, is its excellent safety record. It is absorbed very quickly by the soil, inactivating it - bacteria then biodegrade it. This means that it can be used to control weeds amongst the plants you want to keep. The only proviso is that it may last longer in the ground on very sandy soils, and like any herbicide, should not be used where there is a risk that spray could blow into water.