This is the secret potting ingredient I use to water my plants less – and it keeps slugs at bay, too
It's become a gardening staple
If there’s one potting ingredient I swear by, it’s an unlikely one: sheep’s wool.
My potted plants have thrived every year since I discovered it for gardening, and it’s all thanks to its water-retaining benefits. Even in peat-free composts, which tend to dry out quicker, I’ve found I can water my plants less than I usually would – and that’s especially handy in hot summers like this one.
There are several ways you can use wool in potted plants, so I’m about to break down the ready-made composts I use and the pellet method I just discovered on Ish Kamran's (@gardening.with.ish) Instagram reel.
What you'll need
I have great success growing my potted plants in this compost every year.
Mix these wool pellets into your compost to improve water retention.
I also use this peat-free wool seed compost to start my plants from scratch.
When I first stumbled upon Dalefoot Wool Compost for Potting (which you can order from Crocus) back in 2021, it completely changed the way I garden. Initially, I chose the brand because it specialises in peat-free composts (I’m a huge advocate for their environmental benefits), but I was pleasantly surprised by the ingredients: nutrient-rich bracken and comfrey, which feed the plant for up to 12 months and, of course, sheep's wool.
Dalefoot Composts claims that plants require 50% less watering in this compost, and I found that to be pretty true. I’ve actually planted all of my tomatoes in Dalefoot Wool Compost for Tomatoes (also available at Crocus) this year, and they managed to survive the few days I was away while there was a heatwave here in the UK (even if the tomato leaves looked a little yellow and droopy when I first came home!). The plants are still pumping out tomatoes, which is so impressive considering the fact that A) it’s been sweltering, and B) they’re in relatively tiny pots.
You don’t have to buy pre-mixed wool compost, though, thanks to the existence of wool pellets.
It’s common knowledge that wool can deter slugs, since the critters hate anything that wicks water out of them, but I’d never really considered adding it to my potting mixes. Until I saw Ish’s Instagram reel, that is.
‘Add them to a tub of water or some really wet compost, and all of a sudden it makes this fantastic little slurry which is soaking in the moisture really, really well,’ says Ish.
‘I’ve been mixing this in with my multi-purpose compost or peat-free compost, which is not very good at retaining moisture anyway, and as a result, it’s been holding onto that moisture just a little bit longer, meaning that I don’t have to worry about my plants drying out so quickly.’
Besides their moisture-retentive and slug-deterrent properties, wool pellets have a few more benefits – and mulching is one of them.
‘If you place them on top, it actually works as a really good mulch layer, too,' Ish says. 'Any sun rays during a heatwave are reflected off of the soil, meaning the soil dries out slower.'
You can buy a top-rated pack of wool pellets from Amazon for £13.99.
‘A double bonus is sheep’s wool is naturally full of nitrogen, meaning when this breaks down, it’s also a slow-release food,’ he adds.
I'm sticking with my sheep's wool compost for the foreseeable – but wool pellets are something I want to try as a layer of mulch, or mixed into other wool-free composts I have lying around.
