soil, it is dormant for two to three months in the time of the cold, dry season until August. Then it will form a generative shoot on which the seeds ripen five months later. One plant is capable of forming up to 1000 tiny seeds, 1600 of which together weigh about one gram. Thus, only relatively few plants are needed for propagation. The plants for cultivation are selected for preferred size and color, then placed 50–100 mm deep in pits with alternate layers of grass and soil to protect them from drying out. They are fertilized heavily, as maca is a soil exhaustive crop. The cultivation cycle is strictly linked to seasonality. Traditionally, land preparation was done by hand. Nowadays, tractor plowing also is used. As maca grows on sites where no other crops can be cultivated, it is often found after long fallows of sheep grazing pastures. Maca croplands thus traditionally are only fertilized with sheep and alpaca manure; however, fertilizer application could prevent soils from depleting in nutrients. Weeding or pesticide application usually is not necessary as the climate is not suitable for most weeds or pests. Nearly all maca cultivation in Peru is carried out organically, as maca itself is seldom attacked. Maca is sometimes interplanted with potatoes, as it is known to maca farmers that the plant naturally repels most root crop pests. Harvest The harvest is done manually, with the leaves left in the field as livestock feed or organic fertilizer. The yield for a cultivated hectare may reach an estimated 15 tons in fresh hypocotyls resulting in around 5 tons of dried material. According to the Ministry of Agriculture of Peru, however, average maca yields for 2005 were only 7 t/ha, with a great variation between different sites. Although maca has been cultivated outside the Andes, whether it develops the same active constituents or potency outside of its natural habitat is not yet clear. Hypocotyls grown from Peruvian seeds form with difficulty at low elevations, in greenhouses, or in warm climates. Nutrition The average composition, on a dry matter basis, is 60-75% carbohydrates (mostly as polysaccharides), 10-14% protein, 8.5% dietary fiber, and 2.2% fats. Phytochemicals Maca contains glucotropaeolin, m-methoxyglucotropaeolin, benzyl glucosinolates, polyphenols, (1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA), and p-methoxybenzyl isothiocyanate. Alkamides are also present in maca. Safety No pharmacokinetic data have been published for maca. The presence of (1R,3S)-1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid (MTCA) in the extracts of maca