Should we be watering our plants with coffee?

·Contributor, Yahoo Life UK
·5-min read
Should we be putting our left-over coffee dregs on our plants? (Getty Images)
Should we be putting our left-over coffee dregs on our plants? (Getty Images)

Coffee is life for many of us. From waking us up in the mornings to giving us a boost when we hit the 4 o' clock flop, a caffeine hit can be essential for pepping us up when we need it.

But turns out the brown stuff could also help to perk up our plants, particularly in the winter.

"Coffee can be a great fertiliser for your plants because it contains some of the essential nutrients that they need, such as nitrogen, potassium, calcium and magnesium," explains Nick Drewe, a gardening expert from WeThrift.

Coffee is an especially great source of nitrogen, which your plants need to produce greener, healthier and stronger stems.

"While your plants may not exactly crave a cappuccino, coffee acts as a source of nitrogen for plants which contributes to healthy, green stems," explains Evie Lane, gardening expert at Primrose.

"It also contains calcium and magnesium, both beneficial for overall plant health."

Read more: Best time of day to water plants, and other beginner gardening questions answered

Using coffee to give your plants a pick-me-up is sustainable too. (Getty Images)
Using coffee to give your plants a pick-me-up is sustainable too. (Getty Images)

As well as helping your plants to thrive, giving your plants a caffeine pick-me-up could also up your sustainability credentials.

That's because despite its brown colour, coffee is considered to be a ‘green’ compost material because it is essentially kitchen waste.

"A healthy compost mix should contain even amounts of both greens and browns," Drewe explains.

According to Drewe, greens include kitchen waste products such as coffee or eggshells, as well as any other fresh or ‘green’ products like fresh grass, clipped flowers or even weeds.

Browns, on the other hand, include any carbon-rich products such as fallen leaves, dried grass, wood chips and paper - including paper coffee filters.

And fertilisation is not only the benefit that coffee can bring to your plants’ health, the morning pick-me-up is also a great natural pesticide.

Coffee ground, Coffee residue is applied to the tree and is a natural fertilizer, Gardening hobby
Want a coffee? Giving your plants the grounds will help them thrive. (Getty Images)

"Spreading coffee grounds around your plant will make them less susceptible to damage from pests such as slugs," Drewe says.

"It is thought that a combination of the high caffeine content and the abrasive texture of coffee is off-putting to slugs and may be enough to deter them from munching on your plants."

A particular benefit of feeding coffee to your plants during winter is that you are naturally going to find fewer ‘green’ products for your compost since there is less growth of natural products like fresh grass and flowers outside.

"So coffee is a natural and organic way to get ‘green’ fertiliser into your compost when other products such as fresh grass are less readily available," Drewe adds.

"Coffee is also a particularly useful fertiliser in the winter months because coffee grounds will still work their way into the soil during freeze-thaw cycles, whereas other products may end up freezing in cold or snowy conditions."

Read more: This ice cube watering hack could help keep your house plants alive

Coffee can perk up your plants. (Getty Images)
Coffee can perk up your plants. (Getty Images)

If you don't have a garden, the good news is that most indoor plants will benefit from the extra boost in nutrients that coffee grounds provide too.

"Coffee grounds can be used for most houseplants for very similar results," Drewe says. "Diluted coffee will continue to work as an efficient and organic fertiliser for a much healthier looking houseplant."

"However, the plants that find coffee grounds particularly beneficial are typically outdoor plants which include blueberries, hydrangeas, hollies, azaleas and the vast majority of trees," Drewe adds.

Interestingly, when coffee grounds are introduced to soil, they will naturally create a more acidic pH which will encourage flowers to bloom blue rather than pink, red or white.

"It is not hard to see why blueberries and blue hydrangeas benefit so much from having coffee in their diet," Drewe explains. "Hydrangeas specifically will bloom better in soil that is consistently moist, so you may want to consider using diluted coffee grounds to get the most out of this plant."

Watch: Money-saving gardening hacks

How to 'water' your plants with coffee

Whether you are sprinkling coffee grounds or pouring diluted coffee into your plant fertiliser, Drewe says you'll get the best results if you apply the coffee thinly to the soil and at least a couple of inches away from the plant’s stem.

"This will help to avoid the stem being damaged as the plant won’t soak up too much of the acidic coffee too quickly," he explains.

If you are using coffee grounds, be sure to rake them into the soil to avoid clumping, as the coffee will be more effective the more it is spread out.

"You may find that you see the most benefits if you dilute your coffee before feeding it to your plant, approximately a quarter cup of ground coffee to three-quarters of water is thought to be the optimum solution," Drewe continues.

"Diluting your coffee will naturally help it spread, and introducing it to your soil as a liquid may help it to soak up quicker."

Read more: Easiest ways to get children into gardening

Coffee isn't just a good pick-me-up for people it's also good for your plants. (Getty Images)
Coffee isn't just a good pick-me-up for people it's also good for your plants. (Getty Images)

But before you fling the dregs of your coffee at your favourite houseplant, it’s also important to remember coffee grounds can be acidic, so you shouldn't use coffee on your plants daily.

"You also need to ensure you’re diluting it in enough water," says Lane.

"Diluting coffee grounds or a shot of espresso in a litre of water gives it the caffeine kick it needs. A good rule of thumb is to feed and water your plants once a week with the weak coffee solution."

And while you'll struggle to find any plants that will not benefit from being fed coffee, certain plants should only be fed coffee in moderation.

"While azaleas, hydrangeas and bromeliads are all acid-loving plants that cannot get enough coffee, roses are not so keen and can sadly end up with a burnt stem if they are overfed," Drewe explains.

Watch: Top gardening hacks you all need to know