Question
yellowing phalaneopsis
I have a phalaneopsis plant that looks like it's dying. I treated it with Physan 20 when I noticed one leaf was turning black and rotting. I cut off that leaf with sterile shears and then treated it again about 2 weeks after. Since then I have noticed that the whole plant is now turning yellow. I have always placed the plant near the window sill with low light. There is no evidence of new leaf growth; only a new stem that's starting to protrude. I repotted the plant this past August and trimmed off all the dead or dying roots. The bottom roots seem okay, but it's just the aerial roots that are dying. I also mist the aerial roots to help keep it from drying out, avoiding water on the crown. Is this yellowing a natural process for regrowth or is my plant dying?
AnswerAshley, if you lost quite a few roots, that could be the cause of the yellowing. Roots provide nourishment for growth. If roots which support a leaf are lost, the leaf will not survive. The leaf will turn progressively yellow and, finally, fall from the plant. You need new root growth which will support the development of new leaves. This new root growth will come principally from those roots down in the potting mix. That process will be facilitated by the repotting you did. Aerial roots are generally not important for potted plants. Those roots reflect the fact that the ancestors of your plant grew in the trees in a humid and airy environment. Pot culture does not generally permit the development of high humidity far from pot, so aerial roots stop growing when they are far enough from the potting mix to lose the needed humidity. The root seals itself to prevent loss of plant sap that flows through the roots. Growing roots in the pot is a balancing act. Generally, it is better to grow it too dry than too wet. Before you water, check to see how much moisture is near the bottom of the pot and only water when the potting mix is dry and then soak it well. Try to use room temperature water and do not use softened water as it contains salt. Since your potting mix is fresh, watering the potting mix thorougly once per week should be fine. With the clear pot, you should be able to moitor new root growth as well as ensure that the potting mix does not stay too wet. Water only in the morning. I do not see any crown rot so you are doing a good job of preventing water from getting into the crown when you water. Try not to let the plant set in any water. After watering place the pot where the water can drain out of the pot for an hour before putting it back into the growing area. I would continue to use the physan 20 every couple of weeks as a preventative until your plant recovers the needed strength to resist infection. Keep your plant warm as cold stresses it (65-80 degrees F is fine). Plants near a window as outside temperatures drop, may get too cold during the night. Phalaenopsis prefer an east window to get some morning sun.
