As winter approaches and outdoor farmers markets wind down, many small businesses that rely on summer sales are now faced with the difficult task of planning for their off-season. To help ensure that fellow market vendors stay afloat until spring, one of those companies, Fox Fungi, has launched a co-op out of its urban farm in south Denver where producers and artisans can continue to sell their products through April. “We’ll be paying the rent on the space either way, so we figured, let’s open it up and see if we can help friends out,” said Rachel Dunhoff of Fox Fungi, which grows and sells a wide variety of cooking mushrooms, including enoki, lion’s mane and shiitake.