Here's a full-body shot of my rubber tree.

Normal.

but I need to ask, because of the accumulated whitish stuff n the surface of the potting mix, does the pot have a drainhole?

If not, transplant into a pot with a drainhole

I think that's perlite.

Planto

Hi, thanks for the responses.

There are three drainholes. Planto is right, the white stuff is perlite.

Here is another pic of the white leaf spots

Hi,
welcome to GW!
I had the very same thing on my ficus benjamina plants. Only on older leaves. I took them for watermarks and haven't wiped them off. Yesterday I noticed some kind of fungi that grew on (from?) the white marks. So wiped all the leaves one by one on 3 plantlets with a vinegar solution.

The secretion is from a normal (but not necessarily a favorable) physiological process called guttation. It occurs when plant turgor (internal water pressure) is high, forcing water from leaf openings called hydathodes that appear near leaf margins . Combinations of over-watering (anoxia), cool/ cloudy weather - especially when humidity is high, soil compaction .... increase the incidence of the process.

Al

This post was edited by tapla on Thu, Sep 25, 14 at 19:26

Thanks Al! I've probably been overwatering :(

Can you recommend any plant biology books / websites that would be helpful to an indoor gardener?

Plant Production in Containers II ~ Carl E. Whitcomb, Ph.D

Water, Media, and Nutrition for Greenhouse Crops ~ edited by David Wm. Reed

Growing Media for Ornamental Plants & Turf ~ K. Handreck and N Black

You'll also want a good basic book that goes into some detail about how plants work (physiology). I can't recommend what basically amounts to an 'entry level' text, but if you want something that goes into a considerable amount of depth re the intricacies (university level texts), you might try:

Plant Physiology (4th edition) ~ L. Taiz & E. Zeiger
or
Plant Physiology ~ H. Mohr & P. Schopfer

The first 3 books cover media, nutrition, - basically cultural influences, and are fairly easy to digest, the later 2 are tomes, and cover the day to day workings of the plant. For those, some science in your background is pretty much a necessity, unless you are REALLY willing to commit to learning what's in the books, no mater the time investment required.

Let me know if you need the ISBN #s.

Al

Many of my plants do this. Living in the hot and humid South, this is kind of unavoidable. My Monstera deliciosa, Ficus elastica "Burgundy" (rubber tree), and strawberry plants are the most noticeable about doing this. Tho, I'd say that my Monstera is the worst. None of my plants seemed to be bothered by this one bit.
To remove the water spots and give my rubber tree's leaves a beautiful, glossy shine, I wipe them down with lemon juice. Lemon juice works great and leaves a nice lemon-y scent. :)

Thanks everyone!

I need help! I have a similar problem. Is this mildew fungus? I've tried vinegar and baking soda sprays and wipe them off but they keep coming back. I bought this plant at a nursery and thought the circle dried spots were from the water so thought nothing of it

Thank you so much photo synthesis! I was so stressed out because my friend's plant doesn't have this problem

I went a snapped a photo of mine. Perfectly natural and harmless.

Can you clean it off so the leaves are dark green and shiney?