Go organic to kill off weeds

Weedkillers can damage health, so it’s time to make the switch to natural products, says Fiann Ó Nualláin

If you are a gardener and you are still using glyphosate and other human toxins as a weed killer it’s high time you changed.

Don’t give me ‘effectiveness’ and ‘convenience’ as an excuse – sure those products kill your weeds quickly but they kill you slowly. We have known the science of it for years, some of us have been shouting about it for decades, the headlines have been full of it for weeks now. Now there is no excuse to drop the over-the-counter lethals and come over to the organic side.

OK, that said – what is on the organic side?

Well we have quite effective organic acids that will kill a wide range of the most common weeds and we

heat treatment from boiling water, steamers or weed flamers to damage the weed beyond a capacity to photosynthesis and so spend enough stored root energy in attempted regeneration that a second passing a few days to weeks later will tip it beyond viability or if an annual destroy it instantly.

We also have manual means – yes, hand weeding and digging out.

There are several alternative weedkillers on the market (including some fine Irish made ones) that utilize the acidity of citric acid, ammonium or acetic acid (vinegar) to destroy the structure of foliage and interrupt normal metabolic functioning of the plant to such a degree as to be fatal to its continued survival. Just like some weed killers but without the damage to human health, they are still chemical in nature so you don’t want to be bathing yourself in it or gargling with it or letting it splash willy-nilly into your eyes.

This ‘disruption burn’ was how the generation of old weedkillers worked before Roundup and other systemic killers — then weedkills became more toxin based and the aim was to get the poison into the leave and carried to the roots and kill it from root to tip.

Glyphosate and some other chemicals in various killer products work by blocking plant enzymes vital to plant metabolism and survival — hence the couple of days to kick in before the plant starts to discolour and die. The organic herbicides will not be a one- application dose in all instances. So the price of your health is patience and perseverance and little extra elbow grease — worth paying.

There are some fine recipes from making your own weed killer — I have put a few out there in the past but I always remind that just because vinegar-based products are having a lot of popularity and success it doesn’t mean that a dash of your kitchen cupboard vinegar will be as effective.

Don’t give up at first go. It will do some damage but may take a few more repeats than commercial mixes— our table vinegar is generally around 5% acetic acid while the commercial product is more industrial at 15-20% acetic acid.

These organic acid treatments are great as spot treatments on individual plants – not as a way to clear an allotment or field. They are ideal to get the weed between the cracks in the patio and pavements. Their drift may damage nearby so always use on a calm day.

With pavements and patios, I favour boiling water to cook the weed and commence it into rotting at the root. Some favour sprinkling salt between this slabs and cobbles.

Salt will draw water out of plant cells and dry them out beyond recovery. The residual salt with make the soil or sand between each slab or cobble more saline and inhospitable to germination and root growth.

The only problem is accumulations of salt will not biodegrade quickly, so be very judicious as to its use. I would not use it between raised beds, border edges or in the veg patch as salinity also damages micro bacteria and earthworms that balance the health of your whole garden. But on a patio — fine.

My heat treatments come when I have overfilled the kettle on a cup of tea and I nip outside with the excess and use it on a weed. Those steamers seem really good but expensive. Flameburners will kill all in path but I’m not a fan. And burning, in general, is not great for our air quality.

If you have a large patch you need weed-free then it is possibly not too late to solarize – a heat treatment to cook off the weeds. Simply covering the area of weeds with a heavy plastic sheet to raise the temps to intolerable over the next four to six weeks. It is traditionally done in July and August but Indian summers are good to go too. If it is gloomy next few weeks, then barrier methods with light depriving membrane will starve the roots of the sun and its role in keeping plants alive. Again, about four to six weeks should do the trick.

Those last methods also have a trick up their sleeve in that by not turning soil you are not turning buried seed up to viability environment and you are not tilthing soil to facilitate germination from blowing-in seed.

The less you disturb the less weeds — this is one of the prime advantages of no dig.

All that said some weeds just need to be pulled by hand and, to be honest, there is a bit of comeuppance in that, making the job a stress buster rather than a stress factor.

I often say gardening is prayer and I do rejoice in all the pleasant parts but to let you in on a secret, I do weed weeds as an offering to the gods — an offering or ridding of my failings and the failings in my life. I weed like I am sacrificing my problems — shedding myself of life’s other nuisances too. Two birds, one stone but why not.

Relax – I don’t do the Azetc face paint or wear a special robe – that’s reserved for planting the shallots and runner beans.