CULTIVATING AND HARVESTING QUALITY MEADOWFOAM

Meadowfoam thrives in the cool, wet climates of the Pacific Northwest and adapts well to poorly drained soils, as it has very low tolerance to water stress.The ideal temperature range for growing this herb is 17 to 26 degrees Celsius.Seeds are sown in late spring, ideally at a depth of 0.6 to 2 cm in soil with temperatures below 12°C and a pH of 5.5 to 6.For mass cropping, plant in rows between 15 and 2 cm.20 cm apart at a density of about 33 to 40 seeds per hectare.Once harvested, this means a productivity of around 110,000 seeds per kilogram of crop. Under optimal conditions, Meadowfoam grows to a height of approximately 25 to 46 cm and, due to its shallow fibrous roots, can be easily transplanted at any stage of growth.Although spiraea flowers have both male and female reproductive organs, they do not mature in sync with each other, so the plant is not self-pollinating.Conversely, at flowering, spiraea requires insect pollinators for fertilization.Meadowfoam requires at least 5 colonies per hectare of crop in good weather conditions for effective pollination.Weather conditions are important because they limit the movement of pollinators and, if unfavorable, can negatively affect fertilization.Inefficient fertilization, in turn, can have a significant negative impact on crop yields.Another factor that can negatively affect final crop yield is competition from other species; Meadowfoam is very susceptible to weeds,especially in the early stages of growth.Taken together, these circumstances make successful mass cultivation of spirea a complex process that requires careful planning and maintenance of the plants to reach maturity. Harvesting occurs when the plant's seed pods are 90 percent mature; this is indicated by the stem turning yellow-green.By the time the mature seeds are ready to harvest, their moisture content should be around 42%.The crops are machine cut and wrapped into piles to dry naturally Stacking when there is early morning dew preserves the integrity of the crop; this helps prevent unwanted breakage, the spontaneous drop of seed from ripe pods. After cutting, the Meadowfoam will dry for 7 to 10 days to achieve a target moisture content of 12-16%.When the target moisture level is reached, the plants will become brittle.Lower moisture levels help threshing crops more efficiently as they are processed for oil production.This plant stores well once harvested if temperature and humidity levels are kept in the low range.

EXTRACTING AND REFINING MEADOWFOAM SEED OIL 

Each spiraea flower contains five seeds, each containing approximately 20% to 30% oil.After the seeds are cleaned and the hulls removed, the oil is extracted from the kernels through a cold pressing process where they are crushed under powerful mechanical presses.Before pressing, the seeds are broken into flour by grinding, flaking or rolling to facilitate the process.Depending on the design of the press, the pressure applied can be as high as 30,000 pounds per square inch and approximately 60-65% of the seed oil can be extracted.Oil yield can be increased up to about 90% by seed conditioning pretreatment, however, this may require altering some of the oil's chemical properties through increased heat and moisture.Cold pressing is the preferred method of extracting oil from nuts and seeds, as it is known to produce the purest oil.After pressing, the residual material (called "cake") may be exposed to a volatile solvent to dissolve the remaining oil (approximately 5 to 15%).The oil can then be recovered from the solution by evaporating the solvent, and the solvent can be recovered for reuse.

Once expressed, Spiraea Seed Oil is refined for optimal performance in a variety of applications.Typically, it is neutralized, lightened and deodorized.Leftover spiraea seed meal can be processed to produce compounds that can be added to the oil for industry-specific benefits.For cosmetic purposes, the secondary metabolite gluconannin (GLN) can be enzymatically converted to 3-methoxybenzyl isothiocyanate (MBTC) and 3-methoxyphenylacetonitrile (MPACN).These compounds can then be added to the oil to give it enhanced skin care properties.Leftover seed meal not repurposed for oil refining can be used in livestock feed (although additional processing may be required to be safe for some species).It can also be used in agriculture as a green manure and to help control weeds, as GLN is known to be herbicidal.