Female flowers emerge and mature before male flowers, ensuring cross pollination. Like oats and barley, wild rice seed is not free-threshing and has an adhering hull which must be removed during seed processing. Seed is green in color when mature and is normally harvested at a moisture content of 35-40 percent. Oregon growers have generally found fall fertilizer application most effective for wild rice production, but this technique relies on heavy clay soils in the paddy and dikes to minimize nutrient losses from leaching. Other nutrients such as P and K are usually not applied unless soil testing indicates a deficiency.
Wild rice is susceptible to zinc deficiencies.
Tissue testing is used in California to determine zinc status of wild rice, however, no cases of zinc deficiency have been reported in Oregon. No herbicides are registered for use on wild rice, and the crop is susceptible to injury from a wide array of herbicides. Several native aquatic weeds have been a problem in Oregon when paddy water levels are less than 12-18 inches. Insecticides are commonly used in other states for midge and rice worm control, however, there have not yet been major pests in Oregon. Algal blooms are common in warm-climate paddy production and can quickly smother wild rice seedlings.