I’m Sick of Watering My Patio Pots Already So I’ve Topped Planters With Cheap Clay Pebbles – and They’re Keeping the Compost Moist Much Longer
Put your watering can away and your feet up: no-chemical clay balls cut irrigation time in half.
Confession: I find watering patio planters such a chore. I adore sitting on the outdoor sofa, surrounded by pots spilling with flowers, and watching bumblebees and butterflies going about their day. But what I don’t love is remembering I've forgotten to water the containers when I’m mid-way through stacking the dishwasher at 9pm. Now, I’m a self-confessed lazy gardener and my pots are full of the most low-maintenance plants possible – but still, I’m sick of having to water them so often.
We all know that plants in pots need watering more than those in the ground, and my patio is sheltered and south-facing so bakes in the sun, exacerbating the problem. And for the most abundant blooms, the compost needs to be kept consistently moist. Dehydrated plants also produce less nectar for pollinators, which is a worry. And heaven forbid I go away for a long weekend in a summer heatwave: unwatered containers become a botanical graveyard to greet my return.
It was quite by chance that I found the solution to reduce watering, when I stopped to chat to an exhibitor at a garden show earlier this year. All his planters were topped with tiny clay balls. Why, I asked, thinking they were simply for earthy-toned aesthetics. You can imagine how my ears pricked up when I discovered it was so he didn’t have to water as often. Within a week, my pots had the same clay balls and guess what? He was right! Now I have planters of cascading stems and colorful flowers without any stress over every-day irrigation.
What are LECA Clay Balls?
These little clay balls are normally used to grow plants hydroponically without soil, as a biological filter in fish tanks or a drainage layer in terrariums. Little pellets of clay are flash-heated so moisture inside turns to steam, causing them to puff up into balls, rather like how popcorn is made. And the result is called LECA which stands for Lightweight Expanded Clay Aggregate, also known as Hydroton.
The clay's now sponge-like texture is extremely good at holding onto water. That’s why LECA is used to grow plants hydroponically: the clay pebbles suck water up from the base reservoir and deliver it to the roots. Used as a planter topper, the balls hold onto water when it rains or you irrigate, then slowly but surely release it to the soil. A layer of clay pebbles atop container soil also slows evaporation, further helping to keep hold of moisture.
Why Clay Pebbles Work for Patio Pots
As well as helping to maintain moisture levels in the potting soil, LECA balls also block sunlight, meaning fewer weed seeds germinate. Unlike bark and composted mulch, a layer of clay balls doesn’t offer a welcoming environment for damp-loving pests or fungus, either. A topping on the surface not only looks neat, but acts as an insulating duvet that buffers plants from temperature extremes.
The balls also stop soil from being splashed onto leaves in heavy downpours, which is super-useful if you're growing herbs. In my trough of strawberries, they’re doing a great job of keeping the fruit clean, too. And because they’re made of fired clay, the pebbles don’t break down so will last for years.
Where’s the catch, I hear you ask. And there is, of course, a downside. As they’re mostly made of air, dry LECA balls are lightweight so can blow away. If yours is an exposed garden, this isn’t the right solution to watering patio pots for you.
How to Use LECA Balls as Pot Toppers
You can buy pebbles of all sizes and for outdoor planters, bigger balls are better. You’ll need a layer that’s at least an inch thick to be effective – preferably 2 inches – so you may want to scrape a little soil out of your planters first. It’s also important that there’s at least an inch between the rim of the pot and the top of the clay pebble layer, too, to stop them blowing away. Very dry balls can also float if torrential rain floods the pot, so you need a buffer zone to keep them where they’re supposed to be.
Soak the balls for at least 12 hours so they’re fully hydrated and water your pots before adding the layer. And that’s it, you’re done!
If you find the clay pebbles do get moved by the wind, spreading a layer of grit over the top will weigh them down. I’ve used hessian to cover them on a tall pot that seems to catch the breeze, cutting a slit so the fabric was easy to slide around the plant stem.
Is LECA Good for Houseplants, Too?
If, like me, you’re an erratic irrigator of houseplants as well as patio planters, then topping pots with clay pebbles indoors will even out any over- and under-watering. This also creates an inhospitable environment for pests, making clay balls a natural solution to prevent fungus gnats. Standing humidity-loving plants such as ferns and peace lilies on a tray of clay pebbles and water also gives them the moist environment they need to thrive.
Some houseplants can be grown entirely in LECA rather than potting mix. Drought-tolerant houseplants that aren’t too sensitive to under-watering do best, such as snake plants, jade, hoya and spider plants. It’s best to only transition young plants, or propagate new plants with LECA, as roots that have grown in soil will find the move difficult.
I hope this solution works to cut watering frequency for you, too. My patio is now lush with cascading stems and hanging basket blooms, and I don't panic when I've forgotten to water.
