Question
QUESTION:        Hi.  I am growing cape sundew seedlings.  They had algae growing in
their soil.  I pulled it out when I saw it.   Now, the algae has begun to grown
on them- onto some of their leaves.  
      I sprayed them with a fungicide.  Didn't seem to kill the algae on them.  
Is there any way to get rid of the algae on them?  Should I cut off the leaves
that have algae on them? Will it spread to their other leaves and kill them?
     Also, if I have a plastic bag over a pot, do I still have to water the pot?

ANSWER: Hi Mae,

Depending on how big the seedlings are, you may be able to just scrape away the algae.  Algae is hard to kill since it is different than fungus.  Algae isn't really a disease, so it won't kill plants directly the way a fungus might, but it can smother plants.

The best way to prevent this is to top water the soil frequently to help wash away algal spores.  You can also sterilize the peat moss before using it by getting it wet and microwaving it until it steams heavily, or steam it in a pot.  Also try to use distilled water if you're not already since even small amounts of minerals can encourage algae growth.  You can also soak your peat in water for a few days first, then squeeze the water out to leach out some of the nutrients that may be feeding the  algae.

Even if you have a cover over a pot you still need to make sure the soil is staying moist.


Good Growing!

Jeff Dallas
Sarracenia Northwest
http://www.cobraplant.com

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

QUESTION: The seedlings are tiny.  They are growing well, but there is alot of algae in their
pot in the soil and on the perilite.  Too much to pull out! I don't want to repot
them again.  I just repotted them a few weeks ago.  I read about using vinegar or
hydrogen peroxide to kill algae.  Have you heard of this? Do you think this
would be safe to use of them?

ANSWER: Hi Mae,

I don't recommend the vinegar; I killed some plants that way.  The peroxide has promise, but the trick is going to be getting the concentration right.  On grower I know used standard 3% (like you get at the drugstore for antiseptic) diluted with 3 parts water.  Try that in a small patch and see how it works.  I know if it's too strong the oxidative action will kill your seedlings also.

There's also a couple product out there that use quanternary ammonium componds.  One is called Physan 20, the other is Consan 20.  They will both kill fungus and algae, but you need to follow directions carefully.  The chemical is a disinfectant and works very well and a preventative anti-fungal, but if it's too strong it will damage plants also.  Vascular plants such as carnivorous plants will have stronger cell walls that algae does.  What you are trying to do is utilize this slight weakness with either the ammonium compounds or the peroxide.

Let us know how it works.  This is very valuable information.

Good growing!

Jeff Dallas
Sarracenia Northwest
http://www.cobraplant.com

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

QUESTION:          Thank you Jeff. :)  I am not going to use the vinegar.  I may try the
peroxide.  If I do, I'll take some of the algae out of the seedling pot and test
the peroxide on it on a paper plate.  If not, I'll just have to pull out as much
as I can.  I pulled out most of the algae the other day.  I see a little more
again.  Will have to pull out again.  
        I forgot to specify to you what algae I have.  The algae I have is not
slime algae.  It just looks like green peat moss.  There's also green spots on
some of the perilite.  I have this in all of my pots that I have covered with
plastic wrap.
        I have the physan20.  I have used it on my pots and they don't seem to
have mold, but it didn't get rId of the algae.  I think it says on the directions
to remove the dead algae from the spray or new algae will feed on the dead.  
I didn't notice any dead algae.  Maybe the spray did kill the algae, but b/c I
didn't see it to remove it, more grew.  
         To avoid problems in the future from covering pots with plastic (etc.),
do I need to cover the pots for seeds to germinate or for leaf cuttings or can
they grow without a bag?  If they need a bag, what if I cut a hole or a few
holes in the bag? Would that work?  

Answer
Hi Mae,

If you cover the pots to block out light prior to germination, that will help some.  Try also soaking the peat moss and draining the water before using it.  It sounds like there is some nutrient content there that is helping feed the algae.


Good Growing!

Jeff Dallas
Sarracenia Northwest
http://www.cobraplant.com