The Fungus Blob versus the Weeping Fig
May 23, 2010 12:12 PM   Subscribe

I replanted my indoor ficus benjimana/weeping fig about two weeks ago, putting it into a much larger pot, and using some Home Depot gardening soil. A few days ago, a thin-foam-like, white substance appeared over portions of the soil. Today, I notice I have large, blobby, mushy, fungus-looking things growing on the top of the soil. The tree, however, looks fine. What is this gross stuff, and should I do anything about it?

....I grew this from a cutting into a 3-foot tall, nice and bushy tree over the past 5 years -- I have absolutely no gardening knowledge, and just scott's miracle-gro sticks and water and a good window position.
posted by not_on_display to Home & Garden (10 answers total) 1 user marked this as a favorite
Probably soil fungus. Maybe you're over-watering? Make sure the soil is reasonably dry before watering, and don't do it last thing at night.
posted by gene_machine at 12:15 PM on May 23, 2010

I'd check on drainage: Is the pot too big and holding too much moisture to allow it to evaporate reasonably quickly? Is it a plastic pot? Does it have sufficient holes in the bottom?

My ficus likes to be dry-ish and pot-bound. Or maybe it just has Stolkholm Syndrome.

I don't think soil fungus just goes away without treatment and I'd be worried about the fungus affecting the integrity of the tree.

I think if it were me, I'd check the soil composition and repot, probably in a smaller pot.
posted by A Terrible Llama at 12:29 PM on May 23, 2010

(Plastic's not breathable, I meant. It's good for plants who are okay with slow wicking away of moisture, but not so much for plants who need a little more air.)
posted by A Terrible Llama at 12:30 PM on May 23, 2010

I'm guessing drainage as well. Did you just use straight potting mix? For ficus you're supposed to mix it 50/50 with perlite and some rocks at the bottom of the pot for best drainage.
posted by rhizome at 1:01 PM on May 23, 2010

Ah, thanks for the tips. Yes, I used straight potting mix. There does seem to be drainage at the bottom of the pot (like, the pot's saucer has liquid in it), but there's not much of a place for the saucer-water to evaporate. Should I just hold off on watering it again until it seems relatively dry? Should I place it in a nicely-shaded space outdoors to facilitate drying out?

Can I eat the fungus? :)
posted by not_on_display at 1:06 PM on May 23, 2010

You don't say what sort of soil you used, but if this was outdoor potting soil, rather than houseplant (peat-based) potting soil, the Ficus could not be getting good enough drainage. Outdoor (topsoil) mixtures tend to be quite solid.
I would repot it, using a peat-based soil (such as Miracle Grow potting soil). The trick with repotting is to move it to a pot that is a little bigger (about 1"-1.5" wider), not a huge pot. Big pots encourage too fast a rate of growth (and other things to grow!). You can cut back the roots a little at the bottom or ends, when repotting, as Ficus roots grow back quickly.
Lastly, don't overwater. Overwatering is the cause of most plant mold. Let the soil get to the "feels pretty dry" stage before watering your plant. This may be every 2-3 days or once a week. Potted plants retain more moisture than you'd think, indoors, especially in humid places like the kitchen or bathroom.
posted by Susurration at 1:06 PM on May 23, 2010

(like, the pot's saucer has liquid in it)

If the saucer water just sits there, they soil is saturated -- otherwise the dry soil wicks it into the plant. You can start alleviating the moisture issue by dumping the saucer out and maybe looking at a way to raise the pot up a little to get some air circulating underneath. Maybe three small jar lids?

Ficuses have a tendency to freak if you move them or if they're rattled because you look at them funny; they'll up and drop half their leaves just to spite you, then they'll be okay. I tell you this in case you're tempted to move him* to a drier spot.

*Ficuses are always 'he' to me.
posted by A Terrible Llama at 1:13 PM on May 23, 2010 [1 favorite]

If it's in the soil and not on living tissue, it is unlikely to harm your ficus-fungus growing on the organic material in soil mix generally does not suddenly develop a taste for live plants. However, once you have soil fungus, it's really hard to get rid of. Spores are in the air, on the plant &c. If you don't like the look of it, you can put down a layer of pea gravel. Letting the top two inches of soil dry out before watering is also helpful, and better watering practice for your fig.

The problem with pots that are too big for the plant is they can get waterlogged. Because I've got a lot of nursery cans, I generally go up from 1 gallon to 5 to 15, like pretty much every nursery does. (Pics of pot sizes here if you scroll down) If you've jumped approximately that much, you're fine. Ficus benjamina can grow quite large if you continue to move it up to larger pots. If you get to a point where you can't go any larger, you can do a root pruning every 3-5 years and re-pot with fresh soil.
posted by oneirodynia at 6:55 PM on May 23, 2010

Yeah, I moved him(?) from about a 5 to a 15 gallon plastic pot. It was in a plastic pot before, too; I blame the new soil. So far, so good, though -- it's not shedding leaves, and hasn't ever, really! This tree's mother (father?) did that a few times. It was scraggly, and this one's pretty bushy, though bent in one direction about 20 degrees off vertical. Also a lot of its lower limbs have grown into one another. I like the effect, but I think it's made the the tree kinda destined to lean.

So as of an hour ago, it's outside on the north-facing porch, under the 2nd-floor-neighbor's porch, the leaves getting direct sun probably only late in the afternoon, but lots of indirect sunlight and breezes. The soil will get indirect moisture and a little direct rain if it's windy when raining. When I moved it, I noticed the saucerwater smelled strong, like a swamp...

mmmm ficusroot soil-fungus-filtered broth....

posted by not_on_display at 4:45 PM on May 24, 2010

The plant has been outside for a few weeks now, and remained hale and healthy, while the fungus quickly retreated. It's even survived being given a good ol' pruning, and is standing up somewhat straighter, with room to fill in a blank spot in the northeastern hemisphere of its canopy.

Thanks for your suggestions!!
posted by not_on_display at 7:33 PM on June 20, 2010

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