As I mention in the video above, I get this question quite often as we move into the fall and the temperatures cool down. There’s no question that when this happens, algae control will become less of a factor and the plant will more or less go away in most ponds…if it doesn’t completely it should at least be less of a problem.
Many algae species (although not all) won’t handle cold temperatures very well, and that’s the main reason they don’t grow as well…that and the sun loses some of it’s summer time punch as well.
Even with this reduction, some of the main or root issues of why algae grows so well in the summer, is still present in the pond. I’m talking about nutrient issues for the most part here…fish waste, phosphates, nitrates and organic build up.
These are still good things to try and reduce and the best way to do that is with beneficial bacteria, which is a natural pond cleaner. You’ll want to look for a cold weather or all temperature bacteria to do this because most “regular” bacteria as well as the natural bacteria that’s present in a pond will go dormant at around 45 to 50 degrees. Cold weather strains can work down to the mid 30 degree range which is great for fall and winter cleaning.
If you keep your fish indoors during the winter (and this is for small pond owners of course) it’s not a bad idea to use bacteria to keep ammonia levels in check in a small body of water.
And for large pond owners, and particularly those that want to get a jump on unwanted growth in the coming spring, as well as work on muck or sludge reduction, a bacterial supplementation in the fall or early winter months (before freeze up) can provide a nice carry over and jump start when things begin to warm up in a few months.