Aquatic Weeds And Algae – What To Treat First

In large ponds there are times when if it weren’t for bad luck, you’d have no luck at all. What I mean is that while pond weeds or pond algae aren’t all that uncommon during the summer, it’s bad enough if you have one of them, let alone both, or in the case of aquatic weeds, several different varieties.

Interestingly and often enough, when you have a big old algae bloom, it may choke off everything else and not allow other plants to grow. The same might be said of things like duckweed. When a pond owner treats the duckweed and clears it, lo and behold, an algae bloom crops up. Such is life I guess. Seriously though, the reason one plant simply took the place of the other is that you really didn’t address the reason the plants are growing so well in the first place. If nutrients are abundant, things will likely grow.

For the scope of this article however I want to talk about what you can do if you find several different plants sprouting up in your pond. In my opinion, it’s important to go at the problem in a logical fashion rather than just trying to kill everything in one atomic blast of chemicals. Namely because the latter approach usually doesn’t work well.

In truth, when it comes to pond weeds you really need to take the time to identify precisely what you have growing in the pond. The reason for this is that different plants require different treatments. And yes I’m speaking primarily about aquatic herbicides here. I don’t like to use them, but there are times when they will end up being the best option for a pond weed problem. My advice though is to target them well and use them wisely.

I don’t tend to like to treat widespread weed problems that are all over the pond. Ideally you want to catch these growths early in the season before they’ve spread too much, then use a topical treatment that’s listed as excellent for control purposes. I often direct people to a very useful website by Texas A & M University called Aqua Plant. There you’ll find numerous pictures and descriptions of aquatic plants, and control options that exist for each one.

Treat The Weeds First

Once you’ve determined the plant and the treatment protocol, it’s best to treat any weeds first. If by chance the suggested treatment is a copper based product like Cutrine or copper sulphate (sometimes these are recommended for weeds), then you may also get some immediate control of any algae blooms too. However remember this important advice: If you have fish and a lot of plant growth and you kill off this growth you will pull oxygen from the water when it dies quickly. You’ll either want to work on the problem in sections over a period of days, as well as have robust aeration running throughout the process to protect the fish. If you don’t do this, you could lose many of them.

In a nutshell, you’ll want to systematically knock each type of weed down with the best prescribed product until the weed growth is cleared. In some cases herbicides may be mixed, and in other cases this may not be advised so you’ll want to consult the manufacturer of such products to be sure.

To be honest, there may be cases when weeds are so heavy or widespread that I simply wouldn’t treat them during the summer. I might wait for the next spring and do my best to get on them early as they start to show up. Sometimes you may get some reduction on submerged weeds by using pond dye, although this won’t work all the time. Still the dye products are non-toxic and safe to use so they may be worth a try.

Next Up Is Algae Control

Once the weeds are in check, it’s possible, and often suggested to begin a beneficial bacteria treatment program as soon as possible. You may need to wait several weeks before beginning the process in order for the chemicals to wear off a bit. For quicker clearing of algae you could certainly use the aformentioned algaecides, but at some point you will most definitely want to begin to build up the good bacteria in the pond again, and there’s nothing wrong with trying to reduce algae in the process rather than add more chemicals to the mix. Note too that copper based products and good bacteria don’t go together as the chemical will kill the good bugs.

The truth is, if you really want to restrict any type of new growth in the future, and you want to avoid chemicals in doing so, your very best bet is to try and restore balance to the pond again by reducing nutrients and organic sediment at the bottom. This can only happen with beneficial bacteria usage, good aeration, and time, but once the pond is cleaner, many unwanted growth issues will simply not materialize.

It’s interesting but many of the weeds that take root at the bottom of a pond, do so because they are opportunistic. The soft, nutrient rich muck is a perfect place for seed pods to drop and take hold. Without this easy access and the abundant compost, many will simply not thrive. By the same token, phosphates and nitrates in the water will be reduced as well and this can often limit algae growth at the surface too. It’s a win/win situation but it won’t be achieved without a bit of diligence on your part.

So you have choices and I’m not here to criticize anyone for trying to improve the look of their large pond. The question is, what’s the best way to get things looking better, and end up making them healthier in the long run? The nuances of each setting will vary somewhat, but by treating the weeds first, then the algae, and then following this process up with a natural plan of overall cleaning and restoration, you improve the chances of having a healthy and clear pond in the years to come.