We have several peace lilies indoors with leaves that first brown at the tips, then the brown extends up the leaf with yellow margins. We are having the same problem with an anthurium. It makes them look quite tatty. Why is this happening?
A few factors can cause this. Dryness is one. If the potting mix dries out for an extended period, it can develop dry pockets that repel rather than absorb moisture, leaving roots permanently dry. If you suspect this is the case, dunk the plants in a bucket of water for 10 minutes or so to rehydrate the mix. Following this, each time you water, take the plant to the sink and give it a good soaking.
Plants that are pot-bound also suffer from dryness issues. Pull plants out of the pot every so often to check the root ball and give them a bigger pot if the roots look crowded. Overwatering can cause similar symptoms. When roots are permanently wet, they rot and can’t take up water. It’s important to get the balance right when watering indoor plants. While it’s good to soak the mix, wait until it’s almost dried out before soaking it again. Don’t leave the pot sitting in a saucer of water permanently – this is a sure recipe for root rot.
A water supply high in sodium will also cause these problems. Your local water authority, or gardeners in the area, may be able to confirm if salt is an issue. If so, rainwater may be your best option. Overfertilising with synthetic fertilisers high in salt will cause plant leaves to burn. If this is the case, shake off old mix and re-pot with fresh mix to give your plants a fighting chance.
For more solutions to gardening problems, including how to get a good, tight head on Iceberg lettuces, pick up the May 2021 issue of ABC Gardening Australia magazine, out now.