design overview DESIGN SUMMARY This greenhouse polyculture design focuses on an in-soil annual crop combination that is suitable for year-round production in an unheated greenhouse. The plan takes advantage of succession planting (using the same area for the production of multiple crops that mature in sequence throughout the year) and relay cropping with the same crop to create an extended production season. This design is very different from the previous two in that uses a very intensive and high density cropping approach to produce year-round, with harvests made in every month of cultivation. One hectare of such a system is projected to have a per hectare yield of approximately 500.000 kilograms of produce per year, using conservative yield estimates. At estimated retail prices for all of these products, the total potential revenues amount to around 2,5 million euros per hectare. There is a great deal of flexibility in the selection of crops and cultivars in this system. The current selection used in this design includes: › › mizuna claytonia › mache › › › › › › › › › beans › red oak lettuce tomatoes green onions onions leeks carrots beets spinach zucchini 50 / 64 › › radish › peas › head lettuce arugula › parsley › bok choy CULTIVATION APPROACH This production of these crops is focused on the annual rotation of four types of plots, pictured in the graphic to the right. Each block represents an area of 10 by 10 meters, with beds of 75 centimeters in width. Over the course of four years, the production cycle will return to same plot where it initially was (plot 1 takes on the cropping cycle of plot 2 in the second year, plot 2 takes on plot 3, and so forth). The cultivation requires very dense crop spacing (much denser than typically recommended)1 year. , and multiple cycles of harvest per Several of the crops are planted over the winter in an unheated greenhouse (onions, greens, root vegetables). During these winter months, growth is much slower than usual, but the cold-hardy crops selected can easily withstand very low temperatures (even freezing temperatures in some cases). These “overwintered” crops can be leſt in the ground and harvested as needed. This also means that crops can remain perfectly fresh without the need for storage or refrigeration, and the overall crop losses can be reduced. With this naturally-extended storage time, growers can have more time to spend on getting their crops sold in local markets. 1 The recommended planting distances are derived from the “Winter Harvest Handbook,” which also presents the results of similar succession cropping cycles at a farm in Maine, USA. • The design is flexible and crops can be switched out on a yearly basis if they are not selling at the desired rate. The crops sold in winter are also somewhat limited in this particular design, but these can easily be expanded to include turnips, turnip greens, Swiss chard, watercress, fennel, kale, and broccoli. KEY BENEFITS With each plot in constant production, the potential yields of the system are very high. This polyculture approach offers the additional potential benefits: • Crops are produced year-round without supplemental heat or lighting, which also results in some cost savings to the grower. • Winter-grown crops can be left in the ground for harvesting as needed, saving on storage costs. Pagina 49
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