Should you really give your plants leftover pasta water? A horticulturist explains the risks of this viral trend

TikTok is full of handy hacks, but when influencers started sharing the latest house plant hack it left us wondering: 'should I be giving my plants pasta water, too?'

It's suggested that the starchy pasta water can be a way to fertilize your houseplants naturally.

'There are a number of everyday household items (such as banana peels and eggshells) that can theoretically be repurposed as feed for your growing houseplants; pasta water falls into this category,' says Andrew Gaumond, horticulturist and editorial Director at Petal Republic.

'The theory goes that pasta water retains some of the starchy nutrients derived from the boiling of pasta which typically comprises eggs and flour.' But is it something we should all be doing to keep our houseplants happy and healthy? Andrew lifts the lid on the popular hack below.

Should you be giving your plants pasta water?

'Some studies indicate that the addition of starch to a soil base can help to accelerate the growth of microorganisms that in turn support the growth, development, and general health of plant life,' says Andrew of Petal Republic.

So starchy water from pasta can be beneficial to your plants, but shouldn't necessarily be given on its own without other proprietary fertilizer designed for houseplants.

Andrew adds: 'Pasta water (unsalted if possible) might be one option you rotate into your seasonal fertilizing schedule alongside a standard, pre-made, plant-appropriate feed.'

What are the benefits of using pasta water on plants?

By reusing water you're saving money and repurposing household waste. 'Pasta water is a byproduct of a process you've already undertaken, so in essence, that makes it eco-friendly and very cheap,' says Andrew. Plus, you can think of it as a way to fertilize your houseplants naturally.

(Image credit: Ivyline)

What type of pasta should you use?

If you are using pasta water on plants, you need to remember that it must be unsalted.

Andrew says: 'A crucial point to be aware of is that pasta water is typically salted (often quite heavily). If plants are given too much sodium it can immediately affect the nutrient base in the soil in a negative way and also cause your plants to quickly dehydrate as the salt sucks out the moisture. 

'However, boiling pasta without salt is a big no-no though, so it's a slight quandary. One option might be to water down your pasta water, but I'd be very cautious.'

Where possible, you'd also ideally want to utilize byproducts from an organic source that is free of any potential additives or preservatives. 

'Pasta that's made from strong, organic white or wholemeal flour and organic eggs would be preferable,' suggests Andrew, adding: 'It's best to avoid any dyed kinds of pasta.'

How should I apply pasta water to plants?

'Simply allow the pasta water to cool to room temperature and pour in and around the base of the plant with a watering can,' advises Andrew.

Is pasta water more beneficial for certain types of plants?

With any homemade fertilizer or plant supplement, it's tricky to ascertain the amount and balance of nutrients you're supplying. 

'Most plant fertilizers are specifically engineered to meet the inherent needs of a certain type of plant and follow a precise ratio of nitrogen, phosphorus and potassium (NPK),' explains Andrew.

'It would potentially be more helpful for larger-leafed tropical plant specimens such as a Monstera, Bird of Paradise, or Areca Palm. 

'I wouldn't recommend it for delicate, flowering plants such as orchids which can be very sensitive to inappropriate nutrient supplements.' 

Is it true that pasta water is good for plants?

Yes, it's true that starchy nutrients derived from boiled unsalted pasta water can be good for plants.

However, instead of using it as the sole fertilizer for your plants, you could instead rotate into a fertilizing schedule that also includes a standard, pre-made plant feed.