Written by James F. Burns
The best control is prevention. Preventing lake weeds from infesting your pond or lake is the single most important part of lake weed control. The methods are simple, and straightforward. One is a matter of vigilance, and the other a matter of good management practices. Most of our lake weed problems are with weeds that are not native to our area, therefore, the best method of controling them by prevention is to avoid introducing them into your pond or lake. Prevent non native lake weed problems through vigilance This is a simple matter of making sure that anything that might have been in an infested pond or lake does not make it into your reservoir without a good inspectin and cleaning. This includes boats and fishing tackle, trailers and anything else that went into or near the water. Sometimes animals, and even runoff from other water bodies may be a problem. There is not a lot you can do about natural causes, but they account for only a very small fraction of invasive lake weeds. Most lake infestations come from human carelessness. Lake weed prevention through good management Have you ever noticed how lake weeds start in the shallows? There is a reason. It is because light can reach the bottom. Lake weeds cannot grow without sunlight. It is as simple as that. If you can prevent the sunlight from reaching a depth of more than about 20 inches, you may still have problems in areas that are very shallow, but you will be able to prevent lake weeds from starting in other areas. The method is pretty simple. Here are the steps:
- Determine the pH. I put this first, because it is something you should do to make the rest of this exercise success. It should be between 6.8, and 8.6. If it is not, correct it by using lime as described in the lake weed control section of this site.
- Determine sechi depth. This is the depth that light can penetrate water. This will tell you what your next step should be. If the sechi depth is under 1 foot, your lake is too fertile, and you need to do something to reduce it's fertility, like planting a vegetative barrier, reducing fertilization around the surrounding area, or increasing water exchange. You can find the answers you need in this section.
- Fertilization. If the depth is more than 24 inches, you need to fertilize. Fertility will cause algae bloom, which will result in reduction of light penetration, which will reduce the chances that lake weeds will spring up. The information you need to accomplish this can be found here.