Hi, My peace lily is flowering but the leaves are mostly yellowish. It sits by north east facing backyard glass door. I water it every 1.5 weeks and let water drain out of the pot. It’s a large pot not sure of the size. I potted both my peace lilies together about two months back. Can you please suggest how to get lush green leaves back?
Thank you for contacting Toronto Master Gardeners for help with your Peace Lily. And thank you for your excellent photos. They help rule out some possible reasons for the yellowing.
First a note: yellowing of some leaves is normal for Peace Lillies. It is normal aging and occurs in the older leaves around the bottom of the plant. From your photos many of the yellow leaves are at the bottom, but I also see others in the middle of the plant. Perhaps age is the culprit, perhaps not. If they are bothersome to you, cut them off (don’t pull). However I discuss some other possible reasons for the yellowing of leaves below. And here is a link to UBC Botanical Gardens that also gives a great overview of yellow leaves on the Peace Lily. yellow leaf
I see that your plant is close to the NE window so it is likely that it is receiving sufficient light for normal photosynthesis. However if your plant receives direct sunlight in the morning through that window please move it away from the window so it receives indirect light. And there appears to be no brown leaves. This fact, according to UBC Botanical Gardens reference, suggests it is not overwatered. Your method of watering sounds excellent.
Peace Lily likes to dry out before watering: you can determine when to water by sticking your finger into the soil to your first knuckle. If the soil is dry at this point it is time to water. However they do not like to be bone dry and this might cause yellow leaves that eventually turn brown. Please check soil every time you water.
If you repotted two months ago, the plant is likely not rootbound, which is a common cause of yellow leaves. A sign for this is that the new growth sprouts at the edges of the pot.
Here is the process of replanting into a larger planter. If you did all this when you combined the two plants it is unlikely that repotting is the cause of the problem. To replant choose a larger pot than the existing pot(s) and fill about half with indoor plant potting soil (don’t use soil for outdoor gardens). Some plants don’t thrive in pots that are too large for them, but your pot looks about right. I suggest you add a slow release good quality fertilizer for indoor plants to the potting mix soil if the soil does not have it in it already. Remove your plant from its existing pot, shake some of the dirt off and look at the roots. If they appear densely packed, tease them apart. The smaller roots with tiny hairs are the most active so be careful not to damage the rootlets. Return the plant to the new pot. (You may need to add more soil under the plant, as the soil should be at the same level on the plant as it was in the previous pot). Don’t forget to leave 3-5 cm (1-2″) above the soil to the top of the pot to allow sufficient watering. This method and some other useful information is describe here. Poorly Peace Lily
Finally, yellowing might be a sign of an infestation. Lily Pests Look carefully at the yellow leaves to see if you see any signs of insects. Mealy bugs look like small clusters of cotton and may be seen at the leaf axils. Treat with horticultural oil. Scale can be a cause of yellowing leaves in houseplants and appear as brown blisters or white scales. Spray with a insecticidal soap but this may be ineffective. Aphids can cause yellowing and are also treated with insecticidal soap.
If none of the above is applicable to your combined plants, it may be that they have yet to adjust to their new pot and soil. Time will tell.