Water Treatment in Nursery Ponds with Pond Saver
One potential market for Pond Saver is the nursery irrigation pond. Such ponds are used to supply water for irrigation of the container or bed nursery. This pond is a special situation that needs careful monitoring of certain parameters in order to keep your water clean using bacterial treatment.
Water Recycling Concentrates Fertilizer
A common practice in nurseries is to recycle the irrigation water back into the pond. This means that the water cycling back to the pond carries with it a significant load of fertilizer that leached from the pots or the beds. So fertilizer is constantly being returned to the pond. The concentration of fertilizer increases, particularly when the water level drops during dry periods. Algae blooms and odors are frequent and severe. Depending on the age of the pond, the bottom sediment layer is likely to be thick and nutrient rich. Moderate Pond Saver application rates may not effectively clean the water in these situations. Proper treatment will depend on the amount of fertilizer in the water, and to some degree, in the bottom sediment.
Test the Water
For a nursery pond, in order to establish a proper treatment schedule for Pond Saver, you must first determine the amount of fertilizer in the water. The water should be tested for NPK, for DO (dissolved oxygen) and for pH. Once the NPK is determined, this value should be considered in your fertilizer regime, so that less fertilizer is applied to account for the NPK in the water. This is important to halt the continual increase of fertilizer load into the pond. Periodic testing of the water should be a routine part of the pond maintenance program. Once experience is accumulated, a single annual test may be all that’s required to effectively monitor NPK levels in your recycled nursery pond water.
Test the Sediment
For a complete picture of the task at hand, a sample of the bottom sediment should also be tested for NPK. It is very likely that excess fertilizer is being deposited in the sediment, as more and more fertilizer accumulates in the water. The sediment acts as both a sink and as a reserve for pond fertilizer. Ponds with very high levels of NPK in the sediment may exhibit lush bottom growth, which may extend to the surface in shallow water. In deeper areas, anaerobic conditions may exist. A measure of the approximate depth of the bottom sediment is also a useful indicator of the degree of eutrophication (gradual increase of nutrients) that has already occurred.
If bacterial treatment is to be effective in situations where significant amounts of fertilizer are regularly being added to the pond, aeration is essential. Without it, water quality will drop dramatically, as the bacterial populations will quickly reduce dissolved oxygen. The pond will develop odors, as anaerobic processes become established in scattered pockets throughout pond. Good aeration will go a long way toward correcting and preventing these problems.
Double the Application Rate
For nursery irrigation ponds with high fertilizer content, twice the normal application rate of Pond saver is advisable, particularly for the initial application. If it is not economically feasible to do this throughout the year, increase the initial dose as much as economics will allow. For ponds of significant depth, you can cap the depth at 6-feet for calculation purposes. It is not necessary to include deeper waters in your calculation of dose rates.
If you already have an algae problem, deal with this first before using Pond Saver to clean and clear the water. Pond Saver does not kill algae. It is part of an overall program to keep your water clear. If algicides are used, allow adequate time for that treatement to dissipate before adding Pond Saver. Note that algicides may render the water unsuitable for irrigation use.
An effective pond program for recycled nursery irrigation ponds must include:
- Initial water testing for NPK, DO, and pH.
- Include the NPK levels in the water as part of the fertilization regime in the nursery.
- Double the application rate of Pond Saver, particularly for the initial application.
- Effectively aerate the pond.
The bacteria in Pond Saver are harmless to plants, and won’t be any problem your nursery stock. They are more likely to be beneficial.