Hi. Two years ago I bought a yucca plant and everything was perfect until May this year. Plant is getting yellow/green leaves and thin. So I added plant food spikes and I still see no difference. Besides that, the plant was outside over 2 months, still nothing. A year ago, I found worms in the pot but they look like they’re gone. What can I do to fix my plant? Thanks.
Plant food is not medicine and is intended only for healthy, vigorously growing plants, so remove the spikes because they will only aggravate the problem. If you repotted or are considering repotting, that also will not help.
Your Yucca should be located indoors in front of a sunny window that is completely uncovered throughout the daylight hours. It is also best not to move it in and out as that forces it to adjust to the change in light intensity each time it is moved. Plants react slowly to changes in light. It is possible that yours was not receiving enough light for a couple of years and then only recently starting showing symptoms. Moving it outside would not help.
Yucca root systems are designed to survive periods of drought, but cannot tolerate soil that is constantly moist. Either extreme of watering can cause the symptoms that you are experiencing, but not allowing the soil to dry at least a quarter of the way down into the soil is the most common problem. So you may need to adjust your watering.
Even with improved light and proper watering, you will not be able to reverse any damage that has already occurred. It will take some time, but in good light and with proper watering, healthy new growth should slowly emerge.
The worms are not very pleasant aesthetically, but they are not harming the plant.