Monday 17 June 2019

Diarmuid Gavin: 'Ditch the chemicals and tackle garden weeds and disease with these eco-friendly practices'

Natural born killers

Alyssum Flowers
Alyssum Flowers

Diarmuid Gavin

We've got used to gardening in a certain way. We follow styles and a desire to tame nature, to grow perfect plants while valuing precision and a neat and tidy aesthetic. We hold these gardening principles dear and many of the chemicals which we use to kill weeds, green up lawns, eradicate moss, promote growth, extinguish insects or tackle diseases with have been our gardening aides for generations. Not all of these products are good for us or our planet.

Glyphosate, the main ingredient in Roundup and other weedkillers, was given another five-year license by the EU in 2017, despite concerns being raised over its potentially carcinogenic properties. However, as we become more environmentally-aware it will become obvious to us that the use of many products which we purchase liberally is unsustainable.

Another threat to traditional gardening is the increase in plant diseases and pests arriving into Europe. Xylella fastidiosa is the latest bacteria to represent a potential major threat to the horticultural industry. Outbreaks so far in continental Europe have caused destruction to olive trees in Italy and it has spread to France and Spain. Many of our old favourites such as lavender and rosemary may also be at risk from this disease. Box blight has been a plague for some time now and if a plant cannot be grown without chemical intervention, should we drop it from our planting palette?

What will this mean? It will mean embracing gardens that aren't perfect. I forecast that habits and practices which are widely accepted now will be increasingly challenged.

In the meantime, we can do our bit in our own plots and reduce our reliance on chemical warfare. Here are some ways to go greener this year:


Exchange chemicals for home remedies

There are a number of tried-and-tested and surprisingly effective home-made remedies for common garden problems, and they're easier on your pocket too! Recycle a kitchen spray and get mixing. For example, one part cow's milk to two parts water can be effective against blackspot which can plague roses in warm, wet conditions. Chamomile tea makes a safe fungicide and can be used to prevent damping off disease in seedlings.

You can also sprinkle cinnamon powder around seedlings. Baking soda mixed with some veg oil and water can be used on leaf blight, powdery mildew and as a general fungicide. Similarly an infusion of chopped garlic, veg oil and water can be a good insecticide. Methylated spirits can be used to remove woolly aphids from the trunks of fruit trees. Just soak a cloth and vigorously rub the insects away.


Hand-pick or hose

As gardeners of relatively small plots, we have a big advantage over the large commercial growers. Simply picking off aphids as they appear and crushing them, or hosing down affected plants, will reduce the need to spray.


Strategic weeding

The best way to keep weeds under control is by hoeing annual weeds and digging up perennials. A good thick mulch, several inches ideally, will also suppress weed growth as well as retaining moisture in the soil. Plant ground covers such as pachysandra, ajuga or alchemilla in larger areas. Use boiling water on weeds in gravelled or paved areas or a flame gun.


Adopt a more relaxed approach to what you might otherwise think of as weeds. For example, nettles are a wonderful breeding ground for the larvae of butterflies as are thistles, docks, sorrel weed and meadow grasses. So consider leaving a little patch of your garden uncultivated, which the weeds will colonise quickly.


Attract natural predators


Natural predators such as the ladybird (above) will hoover up aphids. They like herbs such as mint, chives, coriander, fennel and dill and flat-topped flowers such as yarrow. Include calendula, statice, alyssum (pictured above) and cosmos in your flower beds. They (and hedgehogs) need places to hibernate in winter. They naturally overwinter in crevices of bark on trees and in piles of leaf litter. You can create your own ladybird house by using a simple wooden box and adding bits of bark and leaf litter. Or make a log pile using a few branches, logs and twigs in an out-of-the-way area where they won't be disturbed.


Clever cultivation

Good cultivation practices such as crop rotation, companion planting, choosing the right species that will thrive in your particular micro-climate, growing disease-resistant cultivars, best practice hygiene (cleaning tools etc) and maintaining plant health with correct planting, nutrition and watering will all reduce the requirement for chemical intervention.



Slugs and snails are the bane of every gardener's life but use up your leftover coffee beans and crushed eggshells to create rough barriers around precious plants. Copper bands are also effective around pots, giving snails a mild electric shock if they try to cross.


Biological controls

Nematodes are tiny parasitic creatures which burrow into other slightly bigger creatures such as vine weevil and slugs and release harmful bacteria and destroy them within a day or so. They are not harmful to humans, pets or plants but only work when the soil temperature warms up. August and September are ideal months for application. You buy the nematodes in powder form and dissolve in water and spray affected areas.


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