Green shiii...stuff growing on my bonsai soil!

[Prizefighter]

Just noticed this growing on my red maple container, any idea what this Is? Should I re-pot?

I have two other maple bonsai that are in non clear containers, what are the chances that those other trees have this stuff growing on the inside as well?

Thanks in advance!

 

[Rodrigo]

I can't really help much regarding the green, but does the container have drainage holes at the bottom? If not, it could be an excess of moisture paired with what looks like organic soil due to the lack of drainage?

 

[ColinFraser]

Clear pots tend to grow algae inside - it will not grow in opaque pots where there's no light . . .

 

[sparklemotion]

Questions: What's your soil made of*? What's the drainage situation like in that container (are there holes? show a pic?).

My guesses are algae or long-fibered spaghnum moss. Both are signs that the soil is too wet, both likely to be exacerbated by light (mutatis mutandis, your opaque containers probably don't have this growth).

*There are a lot of resources on the internet about bonsai growing soil. Many of them conflict. BUT, my bet is that if you find one that's reasonably well thought through and follow it you'll be fine. If you start mixing/matching (or just doing stuff on the fly) you'll be... less fine.

 

[Prizefighter]

These holes have been in the container since potting... I thought it might be excess moisture too, but honestly I've been slacking a bit on watering, and a lot of my trees/plants have been running more dry lately so I'm really not sure.

 

[Prizefighter]

Questions: What's your soil made of*? What's the drainage situation like in that container (are there holes? show a pic?).

My guesses are algae or long-fibered spaghnum moss. Both are signs that the soil is too wet, both likely to be exacerbated by light (mutatis mutandis, your opaque containers probably don't have this growth).

*There are a lot of resources on the internet about bonsai growing soil. Many of them conflict. BUT, my bet is that if you find one that's reasonably well thought through and follow it you'll be fine. If you start mixing/matching (or just doing stuff on the fly) you'll be... less fine.

Soil is a generic potting mix from home depot, not even sure if I have the original bag.

 

[Rodrigo]

Yeah I think it's a combination of moisture left over due to the heavy soil (even if you've been slacking on watering a bit, the bottom tends to stay more wet than the top), and the light that gets to the soil through the container as @ColinFraser mentioned. If you can get it re-potted into better soil, not now but when appropriate, and perhaps use a pond basket from Home Depot rather than a clear container, that should solve your problems and give the roots the aeration they need!

 

[Prizefighter]

Yeah I think it's a combination of moisture left over due to the heavy soil (even if you've been slacking on watering a bit, the bottom tends to stay more wet than the top), and the light that gets to the soil through the container as @ColinFraser mentioned. If you can get it re-potted into better soil, not now but when appropriate, and perhaps use a pond basket from Home Depot rather than a clear container, that should solve your problems and give the roots the aeration they need!

When is appropriate to re pot... or is that a question for another part of this forum. Excuse my ignorance.

 

[sparklemotion]

Soil is a generic potting mix from home depot, not even sure if I have the original bag.

Ok. Your green stuff is algae. Your other trees probably don't have it.

When you say that your plants have been "running dry lately," what does that mean to you?

Generic potting mix is not actually all that great for a lot of plants in a lot of climates (mainly b/c it's hard to water correctly).

I think you should read these:
https://bonsainut.com/resources/introductory-soil-physics.29/ (follow link, then click Download to get the PDF)
https://www.houzz.com/discussions/1378483/taplas-5-1-1-container-mix-in-more-detail

Think about what those mean for your climate (Central Texas has problems that Minnesota doesn't, so I don't want to be dogmatic). Consider repotting with something that's got at least some inorganic amendments.

As far as when... for maples, "late winter" (probably pretty soon for you... whereas here we have 12" of fresh snow and jealousy). The rule of thumb for deciduous trees is "when the buds are extending." More reading: http://bonsai4me.com/Basics/BasicsWhen to Repot your Bonsai.htm

 

[TN_Jim]

The good thing is that algae is harmless. It will uptake nominal nutrients from the soil, yet also be adding some needed oxygen to your soil. I wouldn’t rush repotting on account of the algae.

 

[Rodrigo]

When is appropriate to re pot... or is that a question for another part of this forum. Excuse my ignorance.

Basically as @sparklemotion mentioned: Late winter/early spring. I don't know far south in Texas you are, but here in Dallas we are still dealing with mostly cold weather and none of my trees' buds have even started swelling. Be careful because the buds will swell a bit before they actually start extending/opening so don't get over zealous and try to re-pot too soon. As @TN_Jim said, I wouldn't rush it just for a bit of algae.

 

[bonsaidave]

I get a little bit of this green growing in some chopped in half water bottles. I'm trying to recycle a bit and use them like plug containers for seedlings. Using them for 2 years now and it doesn't seem to hurt anything. My soil is much more inorganic though.
Side note: I start repotting at the beginning of February and work through all my trees throughout the month.

 

[Prizefighter]

Basically as @sparklemotion mentioned: Late winter/early spring. I don't know far south in Texas you are, but here in Dallas we are still dealing with mostly cold weather and none of my trees' buds have even started swelling. Be careful because the buds will swell a bit before they actually start extending/opening so don't get over zealous and try to re-pot too soon. As @TN_Jim said, I wouldn't rush it just for a bit of algae.

Weather is really fucked up were I'm at. It's 60 right now, but has dropped below 20 and then back up to the 60s multiple times since the end of December.

Some of our plants have flowered prematurely and then died off, I'm assuming because of the sporadic weather conditions.

 

[Prizefighter]

Ok. Your green stuff is algae. Your other trees probably don't have it.

When you say that your plants have been "running dry lately," what does that mean to you?

Generic potting mix is not actually all that great for a lot of plants in a lot of climates (mainly b/c it's hard to water correctly).

I think you should read these:
https://bonsainut.com/resources/introductory-soil-physics.29/ (follow link, then click Download to get the PDF)
https://www.houzz.com/discussions/1378483/taplas-5-1-1-container-mix-in-more-detail

Think about what those mean for your climate (Central Texas has problems that Minnesota doesn't, so I don't want to be dogmatic). Consider repotting with something that's got at least some inorganic amendments.

As far as when... for maples, "late winter" (probably pretty soon for you... whereas here we have 12" of fresh snow and jealousy). The rule of thumb for deciduous trees is "when the buds are extending." More reading: http://bonsai4me.com/Basics/BasicsWhen to Repot your Bonsai.htm

Usually I just water when I notice the top of the soil drying out, I've probably only watered twice in the last month.

Thanks for the links.

 

[Gustavo Martins]

Either algae or cyanobacteria (you can tell by their nasty fouling smell) due to moisture + light + nutrients (mostly N or P). Should be pretty harmless...