I have just been given an urn plant but notice there are now brown patches on the leaves. What would be the cause of this?
Aechmea Fasciata – the Urn Plant
Certified GKH Gardening Expert
It could be developing a fungus. Treat the plant with fungicide and see if this helps.
If they turn brown completely, then it is likely a small pest attacking the plant. There are several it could be, including scale, aphids and mealybugs. If you treat the plant with neem oil, it will correct both the pest issue and the fungal issue. Here is more information on neem oil: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
It could also be sun-scorch; if you just got the plant, it could have been left in the sun too long - even 15 mins can burn the leaves of plants used to shade - before it came to you. This will not harm the plant as a whole, but it certainly makes it unsightly. If not too many leaves are affected, you can cut off the brown parts. If the patches keep growing, treat for fungus as recommended above. Just be sure to not let spray stuff accumulate in the "cup" of the plant, as this will cause the plant, which is a type of bromeliad, to rot. After you have sprayed, tip the plant upside down to empty it. By the way, many bromeliad growers still put instruction cards into their plants telling you to water the cups; this is entirely wrong, if you keep the bromeliad in the house. OK for outside, wrong for inside. Water the plant on the surface of the soil, as you would any plant, and allow the soil to become fully aerated to the bottom of the pot between waterings.