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136:), or laid over a framework of hoops or wires. Row covers can be set up outside of any protective structure or placed over crops within high tunnels or greenhouses. In its simplest function, it allows a light frost to form on the cover instead of on the leaves beneath. Outside row covers must be clipped or pinned in place or weighted down on the edges. Inside row covers may be draped to the ground without further attachment.
42:. However, even if colder temperatures are mitigated, most crops will stop growing when the days become shorter than 10 hours, and resume after winter as the daylight increases above 10 hours. A hothouse — a greenhouse which is heated and illuminated — creates an environment where plants are fooled into thinking it is their normal growing season. Though this
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of any field trials that might clarify which to choose. Organic mulches, in addition to retaining heat by insulating, can potentially also add some heat from their decomposition, although they must be properly chosen, as factors such as thermal or chemical "burning" (excess heat, acidity, or both) and
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accompany animal manure used as row-crop mulch. One principle involved is to prefer aged compost over fresh compost for this purpose, as its earlier predigestion by soil microbes ends the early phase of intense heat, low pH, and gut bacteria dominance but still leaves a bit more exothermic potential
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with slits through which plants grow, is used extensively in large-scale vegetable growing. When the plastic is black, its color may absorb more solar heat, but if the plastic is clear, it may provide a greenhouse effect; both concepts are touted in discussions of mulching, usually without citations
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are commercial-sized buildings, tall enough to walk through without bending and sometimes tall enough to operate tractors inside. Sometimes polytunnels are built with two layers of plastic sheeting and air blown in between them; this increases the insulation factor, but also cuts down on the amount
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are transparent-roofed enclosures, built low to the ground, used to protect plants from cold weather. Cold frames are found in home gardens and in vegetable farming. They are most often used for growing seedlings that are later transplanted into open ground. A typical cold frame has traditionally
111:(hoop houses): Whereas a greenhouse has a frame and is glazed with glass or stiff polycarbonate sheets, polytunnels are built with thin polyethylene plastic sheeting stretched over curved frameworks, often extending as long "tunnels".
154:, newspaper cones, baskets, miscellaneous bits of plastic, and mulches such as hay, leaves, or straw can be used as frost-protection that is pulled on and off each day when frost is likely to occur overnight.
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are lightweight fabrics placed over plants to retain heat and can provide several degrees of frost protection. Row covers, being fabric, allow rain to permeate the material, and also allow plants to
66:) offer protection from the weather, such as sub-optimal temperatures, freezing or drying winds, damaging wind gusts, frost, snow and ice. Unheated greenhouses can extend the growing season of
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is used for the heat it gives off to warm a nearby plant. Typically a few centimetres of soil are placed on top of the compost mass, and the plant grows there, above the rising heat.
263:: beds where the soil has been loosened and piled a few inches to more than a foot above the surrounding area heat more quickly in spring, allowing earlier planting.
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Season extension can apply to other climates, where conditions other than cold and shortened period of sunlight end the growing year (e.g. a rainy season).
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245:: many a material placed on the soil around plants will help retain heat. Organic mulches include straw, compost, etc. Synthetic mulches, typically,
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been a rectangle of framing lumber with an old window placed over it. Since the advent of plastic sheeting, it is often used instead of old windows.
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vegetables well into the fall and sometimes even through winter until spring. Sometimes supplementary heating is appropriate when temperatures
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time frame, or the extra time thus achieved. To extend the growing season into the colder months, one can use unheated techniques such as
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are short enough that a person cannot walk inside them, perhaps 2 to 4 feet tall, and the plastic must be lifted to access the plants.
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without holding in the moisture (as happens under plastic sheeting). Row cover material can be laid directly onto the crop (
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The Winter
Harvest Handbook: Year-Round Vegetable Production Using Deep-Organic Techniques and Unheated Greenhouses
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will help keep an otherwise unheated greenhouse several degrees warmer at night and on
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a form of season extension for the grower, it is not the usual meaning of the term.
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The Market
Gardener: A Successful Grower's Handbook for Small-Scale Organic Farming
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Passive solar greenhouse is an elegant solution to extend your growing season
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417:"Row Cover & Insect Netting Options & Uses | Comparison Chart (PDF)"
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Temporary coverings: In smaller gardens almost any type of cover, including
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is any method that allows a crop to be grown beyond its normal outdoor
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Passive heated or low-energy greenhouses: Using principles of
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Sources of Free Heat in a
Climate Battery Greenhouse
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380:The Case for a (Mostly) Passive Solar Greenhouse
74:the greenhouse drop below 32 degrees Fahrenheit.
368:Passive Solar Heating for Greenhouse Operations
40:low tunnels, caterpillar tunnels, or hoophouses
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370:, Garden & Greenhouse, September 5, 2011
394:, University of Massachusetts Amherst, 2008
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197:. Unsourced material may be challenged and
217:Learn how and when to remove this message
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358:, CochraneTODAY.ca, September 18, 2020
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195:adding citations to reliable sources
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392:Geothermal Heat for Greenhouses
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93:ground-coupled heat exchangers
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81:passive solar building design
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91:days. Other systems such as
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406:, Atmos Greenhouse Systems
382:, Atmos Greenhouse Systems
290:New Society Publishers
292:. pp. 119–125.
282:Fortier, Jean-Martin
191:improve this section
421:www.johnnyseeds.com
134:floating row covers
36:floating row covers
16:Crop growing method
334:978-1-60358-081-6
299:978-0-86571-765-7
252:coliform bacteria
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189:Please help
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117:High tunnels
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85:thermal mass
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447:Agriculture
261:Raised beds
142:Cold frames
113:Low tunnels
109:Polytunnels
64:cold houses
60:greenhouses
24:agriculture
426:2020-11-06
268:References
255:available.
207:April 2022
126:Row covers
68:cold hardy
53:Structures
32:harvesting
343:262883165
178:does not
130:transpire
58:Unheated
441:Category
323:(2009).
284:(2014).
89:overcast
243:Mulches
235:compost
231:Hotbeds
199:removed
184:sources
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339:OCLC
329:ISBN
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