The gardening folklore that’s actually bad for your blooms

WHEN it comes to nuggets of advice for nurturing your plants, there are many hardy perennials which have been tried and tested by generations of gardeners.

But some well- used practices are nothing more than myths, according to experts.

In fact, New Scientist magazine says that several of the most common pieces of advice should be weeded out altogether – as they could actually harm your garden.

For example, it is increasingly fashionable for eco-friendly latte lovers to reuse coffee grounds in the garden. This is because they contain a small amount of nitrogen, which can act as a fertiliser.

But studies suggest the caffeine and polyphenols the grounds contain may be toxic to plants and earthworms in high concentrations.

The New Scientist says it may be a better idea to compost coffee grounds, to reduce the levels of the chemicals they contain.

Another gardening old wives’ tale is using vinegar to turn hydrangeas blue. The flowers are known to act as a litmus test for the soil, with blue ones meaning the soil is quite acidic while pink means a pH of 5.5 or higher.

But it only works in two species, with most hydrangeas having white blooms which go green or pink as they age, regardless of the soil’s acidity.

A sprinkling of aluminium sulphate is recommended instead.

The New Scientist also debunks advice to improve water drainage by covering holes at the bottom of plant pots with broken pot shards called ‘crocks’ or a layer of gravel.

It states that the advice ‘disobeys the laws of physics’.

This is because water will not move easily from narrow spaces between particles of compost to the wider ones which separate gravel, according to the experts.

This may slow down its flow, so that water is trapped in a pot and air cannot get to the roots, suffocating the plants.

Meanwhile, many gardeners stake newly-planted trees to protect them from the wind.

However, Linda Chalker-Scott from Washington State University, told the New Scientist that wind stress can be good for them, as it ‘ encourages root growth and trunk thickening’.

As for tying up daffodil leaves, the magazine advises: ‘Leaving them in place ... is a must – they will carry on photosynthesising and storing energy in the bulb.’