Have you ever wondered why winter vegetables like spinach seem to taste sweeter than those bought in summer? Having personally noticed this difference on many occasions, I decided to look into it to understand it better.
Contrary to what you might think, winter-grown vegetables are naturally sweeter. This is not a myth, but a scientifically verified fact.
Natural defense mechanism
This increased sweetness is no accident. It’s a survival strategy for plants in the face of cold. In autumn, cold-adapted vegetables begin to concentrate sugar in their cells. This accumulation of sugar lowers the freezing point of the cells. This enables vegetables to gradually increase their resistance to temperatures well below zero.
Distinguishing a frozen crop from a dead one after severe cold
During the first cold spells, plants that have concentrated sugar in their cells will survive the frost, while others will perish. The difference lies in the fact that plants not adapted to the cold see the water in their cells freeze. This forms ice crystals that perforate the cell wall, causing irreversible loss of the crop.
In contrast, cold-adapted plants prevent the formation of ice crystals in their cells, thus preserving their contents.
So, while crops in an unheated greenhouse in winter may freeze, if they are adapted to the cold, they will stay alive. To differentiate between these two effects, all you have to do is look at the appearance of the crop. A crop that has died as a result of a hard frost has a wet, dark appearance. This effect is irreversible, and the crop is lost. On the other hand, a crop that has been frosted without damage will have an icy appearance that will return to its normal appearance as soon as the sun warms up the greenhouse.
The important thing to remember here: don’t panic when you enter your cold greenhouses on a frosty January morning! The plants are frozen, but rarely dead. Just wait patiently for the first rays of sunshine to warm up the greenhouse. The plants will gradually return to their normal, healthy appearance!
How can I boost the resistance of winter vegetables?
As market gardeners, we can increase the cold hardiness of our crops. The key lies in gradual acclimatization to the cold. Deliberately expose your crops to the first frosts by leaving the sides of the greenhouses open, without covering the plants with row cover. For optimum acclimatization, repeat these steps for 5 to 7 days. This way, your plants will be ready to withstand the most extreme winter cold!
This method may seem risky, but it reinforces the plants’ natural resilience.
Acclimatizing winter vegetables
If you’re planning to plant new crops in the middle of winter, when temperatures are already below 0°C (32°F) outside the greenhouse, use the greenhouse heating for a smooth transition. Start with a temperature of around 10°C (50°F) when you first transplant your crops. Gradually lower the temperature over a few days before turning it off completely.
This transition period allows the plant to activate its winter defense system and make its cells sweet. Once this process is underway, the plant can defend itself against the cold!
This brief plunge into plant biology reminds us just how easy it is to grow vegetables when you work with nature rather than against it. Growing vegetables in winter by choosing varieties naturally adapted to the cold means we can harvest abundance while minimizing our energy impact. Cold greenhouses are a sustainable model, perfectly suited to our northern climates, offering the delight of naturally sweet winter vegetables.
Growing vegetables all year round
Winter growing is more art than science. To avoid a potentially costly learning curve, both monetarily and in terms of time, there’s a lot of value in investing in training. After several years of experience in the field, we’ve documented all our knowledge of winter growing in our course Winter Farming Strategies. If you run a small vegetable farm in a northern climate and want to produce vegetables year-round, this course will help you on your way.
Other resources about winter market gardening are also available:
Je, umewahi kujiuliza kwa nini mboga za majira ya baridi kali kama vile mchuzi zina ladha tamu kuliko zile zinazonunuliwa wakati wa kiangazi? Baada ya kuona tofauti hiyo mara nyingi, niliamua kuchunguza jambo hilo ili nielewe vizuri zaidi. Kinyume na unavyofikiri, mboga zinazokua wakati wa majira ya baridi kali ni tamu zaidi. Hilo si hadithi tu, bali ni jambo lililothibitishwa kisayansi. Utaratibu wa kinga wa asili Upendo huo ulioongezeka si wa bahati mbaya. Ni mkakati wa kuishi kwa mimea katika uso wa baridi. Katika majira ya kupukutika kwa majani, mboga zilizobadilika-badilika kwa baridi huanza kukusanya sukari katika chembe zao. Mkusanyiko huo wa sukari hupunguza kiwango cha kufungia cha chembe. Hilo huwezesha mboga kuongeza hatua kwa hatua uwezo wao wa kukabiliana na halijoto iliyo chini ya kiwango cha sifuri. Kufa kwa mimea iliyogandishwa baada ya baridi kali: Katika kipindi cha kwanza cha baridi kali, mimea ambayo ina sukari nyingi katika chembe zake itaokoka baridi kali, wakati wengine watakufa. Tofauti iko katika ukweli kwamba mimea ambayo haijajipatanisha na baridi huona maji katika chembe zao yakifungia. Hilo hufanyiza fuwele za barafu ambazo huvunja ukuta wa chembe, na kusababisha hasara isiyoweza kurekebishwa ya mazao. Kinyume cha hilo, mimea iliyojipatanisha na baridi huzuia magamba ya barafu yasitokee katika chembe zake, na hivyo kuhifadhi yaliyomo. Kwa hiyo, ingawa mazao katika nyumba ya kijani-kibichi isiyo na joto yaweza kufungia wakati wa majira ya baridi kali, yakibadilika ili yaweze kuishi, yatadumu. Ili kutofautisha kati ya athari hizi mbili, unahitaji tu kuangalia muonekano wa mazao. Mazao ambayo yamefa kwa sababu ya baridi kali huwa na sura ya unyevu na nyeusi. Athari hiyo haiwezi kubadilishwa, na mazao hupotea. Kwa upande mwingine, mazao ambayo yamepigwa baridi bila kuharibiwa yatakuwa na sura ya barafu ambayo itarudi kwa sura yake ya kawaida mara tu jua litakapopiga joto chafu. Jambo muhimu kukumbuka hapa: si hofu wakati wewe kuingia greenhouses yako baridi juu ya asubuhi baridi Januari! Mimea hiyo imefungia, lakini mara chache hufa. Ngoja kwa subira na miale ya kwanza ya jua ili kupasha joto chafu. Hatua kwa hatua mimea hiyo itarudi katika umbo lake la kawaida na lenye afya! Ninawezaje kuongeza upinzani wa mboga za majira ya baridi kali? Kama wakulima wa bustani, tunaweza kuongeza nguvu za baridi za mazao yetu. Jambo la muhimu ni kuzoea hali ya baridi polepole. Kwa hivyo, kwa makusudi, weka mazao yako kwenye baridi ya kwanza kwa kuacha pande za vyumba vya kijani wazi, bila kufunika mimea na kifuniko cha safu. Ili kupata hali nzuri ya hewa, jaribu hatua hizi kwa siku 5 hadi 7. Kwa njia hiyo, mimea yako itakuwa tayari kuvumilia baridi kali zaidi ya majira ya baridi kali! Njia hiyo yaweza kuonekana kuwa yenye hatari, lakini inaimarisha uwezo wa mimea wa kujilinda. Ikiwa unapanga kupanda mazao mapya katikati ya majira ya baridi, wakati joto tayari ni chini ya 0 ° C (32 ° F) nje ya chafu, tumia joto la chafu kwa mpito laini. Kuanzia joto la 10 ° C hadi 10 ° F, kwa mfano, kwa kupanda kwa mimea. Punguza joto hatua kwa hatua kwa siku chache kabla ya kulizima kabisa. Katika kipindi hiki cha mpito, mmea huanza kujihami dhidi ya baridi kali na kuhifadhi chembe zake. Mimea hiyo inapokuwa ikifanya hivyo, inaweza kujilinda dhidi ya baridi kali! Kujifunza kwa ufupi juu ya biolojia ya mimea kunatukumbusha jinsi ilivyo rahisi kukuza mboga wakati unafanya kazi na asili badala ya dhidi yake. Kukua mboga wakati wa baridi kwa kuchagua aina za mboga zilizobadilishwa kwa asili kwa baridi inamaanisha tunaweza kuvuna kwa wingi wakati wa kupunguza athari zetu za nishati. Greenhouses baridi ni mfano endelevu, kikamilifu inafaa kwa hali ya hewa yetu ya kaskazini, kutoa furaha ya mboga asili tamu majira ya baridi. Kulima mboga mwaka mzima Kulima mboga wakati wa majira ya baridi kali ni sanaa zaidi kuliko sayansi. Ili kuepuka uwezekano wa gharama kubwa ya kujifunza curve, wote kifedha na katika suala la muda, kuna thamani kubwa katika kuwekeza katika mafunzo. Baada ya miaka kadhaa ya uzoefu katika uwanja, tumekuwa kumbukumbu maarifa yetu yote ya majira ya baridi kukua katika kozi yetu Majira ya baridi kilimo mikakati. Ikiwa unaendesha shamba dogo la mboga katika hali ya hewa ya kaskazini na unataka kuzalisha mboga mwaka mzima, kozi hii itakusaidia njiani. Rasilimali nyingine kuhusu bustani ya soko la majira ya baridi pia zinapatikana: