Question
QUESTION: My rubber plant was thriving in our north facing greenhouse window.  It got so big that I had to repot (from a 6- into a 9- inch pot)and move it.  It is now near a south facing window and under a small solatube (gets natural light from the roof).  After a couple of weeks, it started to lose leaves.  Nothing else has changed, and the plant is still green, but many of the leaves are gone.  I fertilized it in early October, and I water every 4-5 days.  I'm not sure if I should just wait it out or if there is something else I should try.  Help!

ANSWER: Hi Susan,

Your Rubber Plant is responding to two important changes - a larger pot and increased light.

Repotting is tricky and should never be done unless absolutely necessary. When it is done, it must be done correctly, using the right sized pot, loosening the outer roots of the rootball and matching the new soil with the old. A lot can go wrong during the repotting process. In addition, a repotted plant will need less frequent watering than it did before repotting. It is unlikely that more than once weekly watering is necessary for yours. You may have done everything properly, but most people manage to screw up the repotting so I have to mention that as a possible cause.

Plants do not react well to changes in light. In nature, they put down roots in one locational and stay there throughout their lives. The increase in light intensity from north window to south window is considerable and may be damaging to the older leaves that emerged in the north window light. New growth coming in will be adapted to the stronger light. If possible, it is probably best to move your Rubber Plant back to its original location.

I have written an article on repotting that I will email for free to anyone who sends a request to me at my address below.

Please let me know if any of this is unclear or if you have any additional questions.

If this information has been helpful, please click the Rate Volunteer bar below and enter a rating and nomination for me. I am a volunteer on this site so Ratings are the only compensation I receive for answering plant questions.

Need more information? Visit my website at www.HorticulturalHelp.com
or email me at [email protected]
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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC


---------- FOLLOW-UP ----------

QUESTION: Thanks, Will, for your input.  To follow, I cannot move the plant back to the north facing window, because it is too big and won't fit.  The south facing window is sheltered by an outdoor arbor (covered by kiwi vines), so I don't know if there is actually more sunlight.  There is one small shoot near the middle of the plant that has grown about an inch, so maybe the plant will be okay?  Should I slow down on the watering?  I usually water when the soil at the top of the pot is dry, but the soil beneath (about 1/2 inch down) may be damp. I don't want to do anything else that will shock it.  Also, which address should I send my request for the article on repotting?  I know it will be helpful.  I have 4 new plants (different kinds) that may need repotting by Spring.  Again, thanks for your help!

Answer
Hi Susan,

Assessing light intensity can be challenging and most people struggle with that. It is hard to imagine that there is not an increase in light in the south window, especially at this time of year when the sun is much lower in the south sky and non-existent in the north sky.

That said, I suspect the repotting is the real problem, especially since you have been keeping the soil very moist. If you are like most people, when you repotted you incorrectly added some soil on top of the original rootball. If so, and if you water as soon as that added surface soil feels dry, then the underlying rootball never gets appropriately dry. As I mentioned earlier, repotting is more complex than most people realize and it is rarely done properly.

If you added soil to the surface, remove all that loose soil. Then allow the top inch to dry before you add any water. I would assume you will find yourself watering less often.

The address to request my article on repotting is [email protected]. If you also email me a photo of your entire plant, including its pot, I may have some additional insights.

~Will