{"id":267353,"date":"2023-09-07T11:28:09","date_gmt":"2023-09-07T09:28:09","guid":{"rendered":"https:\/\/www.myfood.eu\/?p=267353"},"modified":"2025-11-25T15:26:55","modified_gmt":"2025-11-25T14:26:55","slug":"growing-under-greenhouse-when-its-warm","status":"publish","type":"post","link":"https:\/\/myfood.eu\/en\/2023\/09\/growing-under-greenhouse-when-its-warm\/","title":{"rendered":"Why growing under greenhouse if the climate is getting warmer?"},"content":{"rendered":"\n

If someone asks you why you should grow your plants under greenhouse, you\u2019re likely to say: \u201cto protect your crops from the cold, of course\u201d. And it\u2019s quite normal to think that because it\u2019s correct.<\/p>\n\n\n\n

But it\u2019s more unusual to hear people reply: \u201cthe greenhouse protects against the heat in summer\u201d.<\/p>\n\n\n\n

So, have you ever wondered why you can see square kilometers of professional greenhouses in the desert? Isn\u2019t it hot enough to grow crops directly in the sun in Tunisia or southern Spain? And even in Europe, why put-up greenhouses when the climate is getting warmer?<\/strong> \ud83e\udd75<\/p>\n\n\n\n

This article is very likely to surprise you and teach you a lot of fascinating things about climate management in greenhouses.<\/p>\n\n\n\n

Because yes, you\u2019re going to see, the greenhouse is very useful, even becoming indispensable for heat management<\/strong>.<\/p>\n\n\n\n

\"Culture
Greenhouse growing and global warming: are they compatible?<\/em><\/em><\/figcaption><\/figure>\n\n\n\n
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Greenhouse cultivation beyond the \u201cgood\/not good\u201d stage<\/h2>\n\n\n\n

Greenhouses wrongly suffer from a poor image<\/strong>.<\/p>\n\n\n\n

Yet they are a way of contributing to locally sourced production. Recent debates<\/a> about organic labelling and the use of heated greenhouses have tended to crystallize opinions around caricatured arguments<\/strong>. Organic producers are looking to protect their market, and that\u2019s normal. This is especially true given the difficult economic climate for organic farming, which has been hit hard by the crisis (rising prices, organic farms returning to conventional farming due to a lack of funds, resale of unused conventional stocks, etc.). However, all subjects are mixed up in the debate. Respect for \u2018natural cycles\u2019, soil-less or soil-less cultivation, heating greenhouses, imported or local produce, etc…<\/p>\n\n\n\n

In fact, there is a slight difference between a pesticide-free local crop grown in the open ground in an unheated greenhouse and a Spanish soilless crop grown in the middle of winter in a heated greenhouse.<\/p>\n\n\n\n

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10,000 ha<\/mark><\/em><\/strong>: that’s the surface area in France devoted to greenhouse cultivation (2\/3 of which is devoted to vegetable crops), representing 6.4 million tonnes<\/mark><\/strong> of vegetables a year, i.e. almost half<\/strong> the national production!<\/em><\/p>\nSource : Vegetables from France et agriculture.gouv.fr<\/cite><\/blockquote>\n\n\n\n

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In practical terms, it\u2019s perfectly possible to grow vegetables under greenhouse in an environmentally friendly, natural way that respects the natural cycles<\/strong> of the varieties. And with global warming, greenhouses are becoming a necessity. And this applies to both professional market gardeners and home gardeners. Climatic hazards (floods, heatwaves, hailstorms, strong winds) are a growing concern for farmers. Today, half of France\u2019s vegetable production takes place under glass.<\/p>\n\n\n\n

But if we have heatwaves, how can the greenhouse not add another layer<\/strong>? Here\u2019s how.<\/p>\n\n\n\n

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Greenhouse effect: would you like some more?<\/h2>\n\n\n\n

Let’s start with a bit of theory.<\/p>\n\n\n\n

Here we’re talking about greenhouse models with bioclimatic features<\/strong>. We’re talking about a closed or semi-open translucent structure, preferably made of glass, supported by a metal frame, designed for agricultural\/market gardening or horticultural production. A bioclimatic greenhouse regulates and maintains the parameters that influence crop growth.<\/p>\n\n\n\n

\"Serre
Professional greenhouse in the desert – Cr\u00e9dit Photo Richel<\/em><\/figcaption><\/figure>\n\n\n\n

Growing in a greenhouse and managing the climate<\/h3>\n\n\n\n

The height of the greenhouse will help to \u201cbuffer\u201d the heat<\/strong>, thanks to the volume of air between the ridge and the ground. In fact, the higher the greenhouse, the more favorably the greenhouse effect is controlled<\/strong>, and the greater the inertia. That\u2019s why Dutch-style chapel greenhouses are so high (sometimes up to 12 meters!). However, they retain 90% of the light (horticultural glass, thin profiles).<\/p>\n\n\n\n

In cold weather<\/strong>, the greenhouse is a natural heating device (the greenhouse effect). In fact, 1m2<\/sup> of glass heated by the sun is equivalent to an 800-watt radiator1<\/sup>. Gardeners who grow under greenhouse are aware of this, as they soon find themselves in t-shirts in winter as soon as the sun hits the windows. In fact, housing architects favor south-facing glazing in passive houses. This is the most ecological (and economical!) way of harnessing the sun\u2019’<\/ins>s energy for heating.<\/p>\n\n\n\n

In hot weather<\/strong>, climate control devices are used to regulate the temperature precisely:<\/p>\n\n\n\n