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Winter Gardening

Friday, November 20, 2015
by Thomas Bryan | Leopold Greenhouse Manager, Division of UW Housing

Winter gardening may seem like an oxymoron, but it is a set of season extension techniques to have your garden growing all winter in even most northern zones in the US. The two main objectives of winter gardening are this: 1. extend the Fall season as late as possible and harvest crops into early Winter 2. extend the Fall season as late as possible and get a jumpstart in very early Spring to harvest in mid Spring. The timing of seeding and transplanting are different for each of the objectives, so planning ahead is key. At Allen Centennial Garden, we are experimenting with the second of those objectives with a 15-foot low tunnel filled with hundreds of onions and scallions destined for mid-Spring harvest. The plants were raised in neighboring Leopold Hall by undergraduates who are part of the GreenHouse Learning Community. 

A few mantras or tenants of winter gardening are: pick the right crops, select a favorable site, proper timing helps, harvest before bolting in Spring, brace for snow and wind, and seal your crops up as tightly as possible. The right crops: spinach, mustard, kale, onions, lettuce, cilantro, chard, carrots, and beets. Most cultivars of these crops should be successful, but look for cultivars with "early", "late", "winter" in their names.

Site selection: full sun exposure, use natural windbreaks, set up tunnels parallel to prevailing winds. 

Timing: Johnny's Selected Seeds and University of New Hampshire provide seeding and transplanting calendars for crops they have successfully overwintered.

Building a winter-proof house for your crops: low tunnels fit in most gardens, are cheap to construct, and can be quite sturdy. They are great for overwintering tender perennials too.  See the references listed below for construction plans and materials lists.  We are using bent 1/2'' electrical conduit for structure, AG-70 weight row cover, 12mil polyfilm over the row cover, metal fence posts to seal in the sides, bricks to seal the ends, 2x2 pine posts and zip-ties to secure the fabric and plastic on the ends. Stop by the Allen Centennial Garden to check out our experiment!


General Resources:

University of New Hampshire Extension

Johnny's Seeds: Overwintering Crops

Johnny's Seeds: Low Tunnel Growing Methods


Overwintering Onions:

Johnny's Seeds: Overwintering Onions

Onion Trials

The Allen Centennial Garden and its programs are funded entirely through private support - it receives no state or tuition dollars. To help support the Garden and continue to make our projects and programs possible, please consider a donation.

Tags: UW Students, Garden Display and Design

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Allen Centennial Garden
620 Babcock Drive
Madison WI 53706

Contact Info
Phone: 608-576-2501
E-mail: info@allencentennialgarden.org

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