Why would I add barley straw to my pond?
Barley straw has been shown to be an environmentally-friendly and cost-effective way to successfully control algae. It is most effective at controlling 'blanketweed-type' algae - the long, stringy algae that often lines your waterfalls or wraps around your pots of plants, even though your water is generally very clear. While barley straw does not necessarily aggressively kill algae that is already present, it does prevent new algae growth.
How does barley straw work?
When barley straw is put into water, it starts to decompose. During the decomposition process, 'hydrogen peroxide-type' compounds are produced that inhibit the growth of more algae. Such compounds are NOT toxic to your other plants or fish. Once the barley straw has started to release the hydrogen peroxide-like chemical, it will remain active for approximately six months, after which time its' activity gradually decreases. Fresh barley straw should be added several weeks before the end of the six-month period to ensure there is no lapse in treatment.
Is barley straw safe?
There have been no reports of harmful effects on fish, invertebrates, or plants when barley straw is used in amounts that aren't so excessive that it removes a large amount of oxygen from the system while it decomposes. Be sure to remove old barley straw from the pond though as it can eventually remove precious oxygen from the water column and/or add to the nutrient load of the system, thereby resulting in an algae bloom.
What options exist for using barley straw?
Barley can be added to your pond in many different forms. Liquid and pellet forms are available and may be a more visually pleasing choice for people who do not want to see the physical evidence of barley in the pond. Liquid and pellet forms usually require applications that are more frequent, but they can begin controlling the algae problem much quicker. Barley pads, bales, and planters are other great ways to get the benefits of barley but with less frequent applications that take more time to breakdown and become 'active.'
When should I add barley straw to my pond?
Although barley straw can be applied at any time of the year, it is preferable to add it to the pond very early in the spring before the growth of algae begins. As the breakdown of the barley is a temperature-dependent microbial process, being faster in summer than in winter, it might take 6-8 weeks for barley straw to become active when water temperatures are below 50 degrees F, but only 1-2 weeks when the water temperature is above 70 degrees F.
What other facts should I know about barley straw?
Submerge barley straw bales, pads, and pellets in areas where there is flowing water. This provides for the most efficient breakdown of the barley and the best circulation of the algae-fighting compounds. Try not to place the barley in a stagnant area of your pond and don't allow it to rest on the bottom of the pond.
Tightly packed bales of barley straw will not allow adequate water movement through the straw. In such a situation, only the surface layers of the straw will produce the necessary algae-fighting compounds and the majority of the straw will have no useful effect if it is left compacted.
Barley straw should not initially be applied during prolonged periods of hot weather to waters that already contain dense algae blooms because the combined oxygen demand from the algal bloom and barley straw could increase the risk of the pond experiencing a decreased oxygen level.
Do not substitute regular straw or hay in place of barley straw as they can actually release nutrients that might increase the chances of an algae bloom, as well as the fact that they do not break down in the same manner.
In turbid or muddy water, it might be necessary to add more barley because the hydrogen peroxide-type chemical it produces can actually be made inactive by mud.