How To Stop and Get Rid Of Pond Scum

Pond scum is pretty much an ugly thing in the backyard pond and usually results from a complete unbalancing of the water system.

You’ll recognize it because of the floating algae that is coalescing into bigger chunks.
The trick is to fish this stuff out (put it on the compost pile)
And then get to work on the real problem, because if you don’t sort this out, it will simply reoccur.

Are you feeding the fish too much or too often?

Stop feeding the fish. I know it’s fun but they’ll do well enough for a bit on the algae itself it you leave them be. Did you fertilize the lawn and get some into the pond?

Excess fertilization will produce a massive algae bloom. The simplest thing here is to do a water change plus the other things below.

This can also happen after you feed the waterlilies. Do you have adequate pond coverage with plants?

We’re looking for approximately 30% of the pond covered by plants to reduce sunlight levels. Remember that sunlight will cause algae to bloom like crazy so we’re trying to limit this.

Do you have enough oxygenators in the water garden?

I generally recommend that you calculate the amount of uncovered footage and divide by three to give you the number of oxygenating plant bundles you need to turn the water clear. While this may sound like a lot, if you purchase the hardier ones (not tropicals) you’ll find that many of them will overwinter in deeper ponds and your problems will be a thing of the past.

It is really important to understand that there is a very fine line between healthy, clear water and green, soupy pond scum.

And that line is a balanced ecosystem in the pond. Without that balanced ecosystem, you’ll always have problems.

So get the plant coverage and oxygenating values right and your problems will disappear.

A reader writes saying she can’t afford to add all those plants.
Doug says: then you’ll have green water. 🙁

What about using pond chemicals to clean the water?

You can do this but understand that chemicals only mask the symptoms. As soon as the chemicals wear off, the problem will come back. So you can continue dosing with chemicals or you can fix the problem.

Doesn’t a pump produce oxygen in the water and stop algae from growing

Pond scum isn’t reduced by pond pumps, but  if you over-oxygenate the water with too large a pump, then the pump is part of the problem.

Small pumps do indeed help oxygen levels and this is good. Most folks with small ponds use too large a pump because the enjoyment is in the water movement.

What about ultraviolet water treatment?

Pond UV lighting works really well particularly in fish ponds where plants get eaten by the fish.

You do have to run the ultraviolet (and the pond pump pushing water through it)  24/7 and it’s expensive with each bulb costing upwards of $100.

If your fish population isn’t high, it is cheaper to put in perennial oxygenating plants to control pond scum.

So the bottom line here is that pond scum can be controlled by all the systems of algae control.

Want updates when I post something new? Click here


Secrets For Starting Your Own Water Lily Seeds

You can really start your own water lily seeds by following these instructions

There are two responses a water lily flower has after it has finished blooming.

  • The first is for the stem to collapse and the flower floats downward in the water with the stem staying straight. No pollination has occurred and you don’t have seeds.
  • The second is for the flower to lower itself on the stem in a spiral and submerge itself all coiled up. Congratulations, you have a seedpod developing.

Collecting Seed

The first step is figure out a way to collect the seed. 🙂 The easiest way is to put the blossom into a cloth bag and allow the seed to mature inside the bag.

The second easiest is to to pick the flower about 10–12 days after it has gone under the water and put that flower pod into a container of distilled water to continue growing.

The third way is to buy them at Amazon.

When To Plant Your Water Lily Seeds

  • As soon as the pod releases the individual seed, you can plant them.
  • Do not remove the gelatin coating on the seed.
  • Spread the seed on soil (use a heavy clay soil — not a potting soil) in a very shallow growing pan — approximately 3–4 inches deep.
  • Cover the seed very lightly with sand. We don’t want them floating away.


Put the growing pan in an aquarium or some water container where

  • the top of the soil will be 2–3 inches below the surface and
  • the water is warm — at least 72F.

They’ll require a great deal of full sunlight at this point so if you’re doing this indoors, ensure they get lots of light but nothing hot and fully direct (in other words, a grow lamp 6 inches above the seed tray is too close but one 18–24 inches above is likely fine.

It will take several weeks for the first seeds to germinate. Leave them alone.

When the first leaves reach the surface of the water, the seeds can be removed carefully and potted up in small individual pots.

It is a good idea to put a small bit of compost into the bottom of the pot before you fill the rest of it with soil.

We need to gently feed our small lilies at this transplant stage or we need to give them a source of food when the roots start growing.

Cover the individual pots with 2–4 inches of water.

Here’s my email newsletter where I pass along gardening tips.

Six Months Later

You’re likely looking at six months for these baby plants to be ready for outdoor planting.

The biggest killer in the seedling stage is algae. If you have string algae in the aquarium, it must be controlled or it can choke out the plant growth.

You have to control this manually as any algaecide (even that safe for fish and aquarium plants) will kill these tender baby plants. Twirl it around a pencil or other small stick (toothpicks work well right up around the baby plants) and pull it out on a regular basis.

Once the seedling roots are filling the pot and running out the bottom holes, they are ready for transplanting outdoors.

And that’s how you start water lily seeds.

But if you can’t do this or don’t want to spend the time, let me suggest you can get a huge range of colors and plants here at Amazon

Check out the other garden solutions on my Amazon ebook list here.

error: Content is protected !!