Expert warns against houseplant hack using sponges to retain water

If you often forget to water your houseplants, you might be tempted to try this new hack we've spotted online. The trick is to put a kitchen sponge at the bottom of your plant pot when repotting. 

This creates a reservoir of water for the roots to drink up when the soil runs dry. Intrigued, and a little dubious, we asked an expert what they thought about this tip... And it looks like it's one to avoid when caring for your best indoor plants.

'To be honest, this is the first time I've heard about this! I never came across sponges when repotting plants,' says Anna from Plant Pet Club (opens in new tab).

'And it raises more questions for me, like: if you have a reserve of water at the bottom of the pot, how do you know when to water? Do you wait for the sponge to dry completely (but how do you know when it is dry)? Or do you keep topping up?'

Anna says that it's likely to create a permanent pool of water that will prevent the free flow of excess water out of the drainage holes. The stale water is then likely to breed fungus and bacteria, smell and prevent aeration of the soil.

'We believe to succeed in plant parenting you have to choose plants suited to your lifestyle and level of commitment,' says Anna. 'You are unlikely to tame such demanding divas as Maiden Fern and some varieties of Calathea by simply placing a sponge at the bottom of the plant pot. 

'You have to interact with plants to understand their needs and meet them regularly,' she adds. 'And isn't it the reason why we choose this hobby – an opportunity to connect with nature, slow down and recharge?'

The sponge trick is also meant to prevent root rot, but Anna points out that roots will end up penetrating and growing into the sponge. This will result in roots sitting in the permanent pool of water. As indoor garden ideas go, we think this is one that will be more trouble than it's worth.

You could try it with a small houseplant that needs plenty of water, such as a small peace lily. These plants will wilt dramatically if not given enough water, but bounce back to life when hydrated.

However, since you can't see what's going on inside, it's quite an impractical idea, and could spark new problems, as Anna explains. Houseplants all need a level of care, and there are always low-maintenance options like succulents, monsteras and snake plants if yours are proving too needy and you want to change up your indoor plant ideas.