Question
I have 5 year old Christmas Cati I love. Yesterday I water the plant and was shocked to see the castus covered with brown raised bumps - lookong like round and oval scabs. Some small some larger 1mm to 1cm big. I tryed to scrape them bud they are ingrown in the the skin of the leaves. The smaller are lighter in color and come off if scraped.  Is my castus sick or it is just some fungus? Please help. Thank you

Answer
Hello Radka,
It appears to be that your cactus has edema, an environmental condition that is caused do to overwatering. This mostly happens when the plant is in a hot, dry area and then suddenly in a moist, humid area. I suggest repotting using a peat-based mix made more porous by adding coarse sand or peat to every three parts of the standard mix. Keep it in the east window. Make sure the pot is free-draining.