Green Alge on Pond
In soil-based and -sided ponds, nutrients constantly enter the water from that soil. Controlling the algae in the water can be a challenge.
Development of a hydroponics area of plants will, over time, remove the excess nutrients from the water and therefore control your algae problems.
For a pond of approximately one half acre you need one large truckload of gravel (acid reacting rock preferably; do not use alkaline reacting) tipped into the pond. Level this out, creating a beach effect with the stone level with the water surface. The stone should be at least 12 inches in thickness.
When water plants are in troduced, the plants feed from the water, not the soil, creating a hydroponics area. The more plants, the more nutrients being absorbed.
The plants are easily controlled by having the beach level with the water so you can drive a tractor or weed lopper over the plants, cutting them back once they have flowered, therefore stopping the plants from seeding and reproducing in other areas of the pond.
Plants that work in hydroponics areas very successfully:
Yellow Flag Iris (Iris pseudacorus) The best plant to use in this circumstance; the downside is that it is on the US Government invasive plant list. There are around 15 varieties of this plant including some that are infertile.
Japanese Water Iris (Iris laevigata) A smaller plant than the Yellow Flag and not so voracious at feeding. It comes in around 14 varieties but will be slower growing.
Water Mint (Mentha aquatica) ? This plant is shorter and is very highly scented as well.
Watercress (Rorippa nasturtium-aquaticum) This is the watercress that you can purchase at your local grocery store. When planted hydroponically the plant is very strong tasting and not suitable for table use.
2008 by Clair Hall
Clair Hall has spent her entire life in water gardening, growing up on her parents organic water plant nursery and fish farm in Hamsphire, England. The family created the Water Wych to keep the farm's pond water clear. While business has expanded to the United States, breeding new varieties of water lilies and irises continues.