Your small potted plants won't survive a hot summer if you use the wrong soil – this is the mix experts recommend
A healthy foundation is *everything* if you want your plants to thrive
Wondering how to fill small pots in the garden? It isn’t as simple as gathering soil from the border – but there is a right way to top them up.
There are plenty of ways to fill the bottom of a large planter, but small pots don’t have as much room for trial and error. They’re far more susceptible to drying out, and because space is limited, it isn't unusual for heavier soils to suffocate the plants growing in them.
I’ve got a few small pots to fill in my own garden, so I set out to find out the best ways to fill them (and ensure I don’t accidentally kill my plants!). Here's what the experts recommend.
What you'll need
This 20kg bag of horticultural grit is a bargain for £6. It's a superhero for improving drainage in small pots.
Perlite is brilliant for drainage and aerating the soil, too, and this 50-litre bag will last even longer.
A peat-free compost provides a lighter base for small potting mixes, and this one's highly rated on Amazon.
If your container garden ideas revolve around small pots, knowing the best way to fill them is more crucial than ever.
You’ll need to make sure you’re giving your plants the breathing space and nutrients they need to thrive. That's why it’s wise to distinguish between garden soil and potting mixes.
‘For small pots, skip the heavy garden soil and go for a light peat-free potting mix,’ advises Julian Palphramand, head of plants at British Garden Centres. ‘Small containers can compact quickly, and thick soil or straight compost can end up choking roots.’
Jamieson Brothers Professional Preat Free Compost, which you can order from Amazon, includes John Innes and feeds plants for six months.
Chris Bonnett, horticulturist and founder of GardeningExpress.co.uk, agrees that using garden soil instead of potting mix is one of the most common container garden mistakes.
‘In containers, garden soil can compact and suffocate roots,’ he says. ‘Proper container mix will remain airy, stay dry, drain well and hold moisture more evenly, supporting plants in their growth.’
Julian already told us that a peat-free potting mix is the best option – it's generally lighter (and a lot more sustainable) than peat-based composts – but it’s a good idea to improve drainage in other ways, too. Pot feet are brilliant in heavy rain, but comfortable conditions for small potted plants start with the potting mix itself.
‘A good all-purpose peat-free mix works best, and if you're growing herbs or plants that hate sitting wet, add a bit of perlite or horticultural grit,’ says Julian. ‘It helps water drain properly and keeps the root zone airy, crucial when you're working with such limited space.’
You can order a 20kg bag of Westland Potting Grit from Amazon, or buy a large 50-litre bag of Hardys Perlite from Amazon.
'Fill your small pot and leave a gap at the top so water doesn't wash compost over the edge,' Julian adds. 'Water slowly at first to let the mix settle. It keeps things tidy, avoids waterlogging and makes maintenance much easier.'
So, garden soil is out when it comes to filling small pots in the garden, but a peat-free, multi-purpose potting mix (ideally, mixed with horticultural grit or perlite) gets the green light from the experts.
Just make sure you keep them well-watered – especially during hot weather!
