Sago Palm is Yellowing

I have had a large Sago Palm since the spring that has been very happy soaking up the morning sunshine near our sliding glass door. Now, his leaves are turning yellow.

We recently got a new well. The water is free of contaminants, metals, and minerals with no hardness at all. The pH is high, though.

Recent changes include:
Cooler temperatures
Less morning light
High pH, mineral free water

I have tried to dilute the high pH water somewhat by adding pH balanced water, but Sago doesn't like to be watered so much. Can any of these factors be causing the yellowing and is there anything I can try to save Sago?

They do prefer the pH slightly acidic, so if you've got pH balanced water on hand I'd water with that instead of the high pH well water. I'd also check whether you're watering too much overall--in cooler weather plants don't go through water as quickly, so if you're watering it at the same frequency you did all summer it could be too much. And I'd also check and see if it's getting cold drafts from being so close to the door.

Sago is watered very little usually. I choose plants that prefer dryer conditions in general.

He seems very attached to the morning sunlight. If the area at the window is too chilly, will he be ok moving out of the sunshine?

I've had a Sago Palm for about 7 yrs as a indoor plant, of course its never going to get as big as they do down south. I do put mine outside during the warmer months but as soon as the temps are consistanly staying below 50 F. I give it a good watering and bring it in for the winter, it stays by an east facing patio door, I wouldn't call it good light but its the best I have for its size. I keep it dry during the winter months, I drag it to the shower in Feb. and water it and clean the fronds at the same time. Make sure when you do water yours you don't water the middle part always water around the trunk the caudex can rot if it stays to wet. I would also check for spider mites. Just hang in there with it and it will do fine. There is a Palms & Cycads Forum with alot of people that have Sagos you might go there and get some info. Good Luck

Plants are a learning experience for me. My sago is a little asymmetrical now because I didn't realize I needed to turn him frequently when he sprouted fronds. He has a few that grew very large on his darker side. He has a lot of character and is my favorite plant. I do know to water him less now that the temperatures are dropping.

The temps here are mostly down in the low 60's lately, though the nights have been colder. Do you leave yours by your window even at night when the temps drop?

I'm pretty convinced it was the high pH water. I don't pour water over him, just into the pot.

As long as it stays on the dry side during the winter it can take the cooler temps inside by a window. My Sago is one of the favorites around here too. As long as the base is healthy it will throw another set of leaves next year.