I have had a Calla Lilly for about 5 years now. No matter where I put it, lounge, utility room, hallway, it just doesn't thrive. There are (and always have been) a few straggly leaves, which eventually go brown. The leaves never grow very big. I've had one weedy flower a couple of years ago. I believe it needs indirect sunlight, fairly warm temperature, and I only water it once the soil in the pot starts to feel dry, as per the instructions I read once. My son has a beautiful, thriving Calla Lily tucked away on a window sill in their kitchen that they utterly neglect, and it puts mine to shame. If anyone has any tips, they would be gratefully received!
I live in Leicester, East Midlands, UK.

I think the primary problem for your Calla Lily is that it has not gotten enough light. Indoors they need to be very close to a sunny window.

Normally Calla lilies are spring bloomers. Yours and ones that are sold now are hybrids that have been forced. That makes future flowering problematic.

For now, provide as much light as possible to extend its longevity, do not repot it, and water the soil thoroughly as soon as the surface of the soil feels barely damp to the touch. Never allow the soil to become completely dry.

Normally, Callas need a dormancy or semi-dormant period after they finish flowering. But because yours may be a forced hybrid, there is no guarantee that it will flower again. During a dormant period of several months, keep it cool and allow the soil to dry out very deep into the pot. Some of the leaves will yellow, but that is expected. Eventually, you should see some healthy new growth. At that time you can resume normal watering and start fertilizing.

Getting Calla hybrids to rebloom is a lot of work and often doesn't work. That is why most people discard their Callas after they have finished flowering.

I have several containers of Calla Lilys, there are located outside during the spring, summer and fall, they get 4-5 hours of sun, watered when it rains and fertilized when I can remember. I try to thin out the rhizomes when they look like they are declining. During the winter, I put the containers in a cool basement and provide minimal water than start the process all over in the spring. The soil is a mix of potting mix and Bob's special compost.

https://www.rhs.org.uk/advice/...

Hello StepSmith, I don't grow them, but I saw them growing in the wild along the bay in San Francisco, in full sun, and weather there is always cool from the ocean breeze. You may want to augment the light in your place and keep it in the temperature range of 15C to 21C if you can. Bay area here is warmer than my side in winter, and cooler there when it goes summer here due to my inland location. You know your place better so see if you can tweak your indoor set-up to help your plant based on this observations that I have seen.

Maybe try if you can to position your plant in an east/southeast facing window during your winter months. Window light orientations differ, north side is always too weak for flowering plants. So often times if I have flowering plants, I position them by my east or west facing window during winter so they can take advantage of the light and warmth. Then as seasons change I just draw the sheer white curtains to protect them from summer heat passing through the glass. Low light does not mean no light. Light helps trigger flowering along with temperature cool downs for some plants. Cool down does not mean either to expose them to freezing temps.

Good luck! Hope your plant can recover.

Thanks everyone! I'm impressed by the speed of response and the quality of all your excellent advice. I'll definitely have to re-think where my Lily is. The utility room it's in has a translucent dome for a roof which gives a diffuse, but not direct light. Since my son's Lily is totally indoors, on an internal window sill (so gets not much light), I thought the dome room (as we call it) would be suitable. Clearly it's not, so I'll move it. Am going to completely dry out the soil too, for the rest of the winter/early spring months. I wasn't aware there could be a dormant period. I manage my indoor cyclamen like this perfectly well every year, so I am familiar with this. Thanks again everyone.