The following excerpt is fromThe Winter Market Gardener(New Society Publishers , October 2023 ) by Jean - Martin FortierandCatherine Sylvestre .
In wintertime , plant increment slows , body of water uptake tapers off , and the employment pertain to craw irrigation wind down . That ’s the good news . The bad newsworthiness is that irrigation in very frigid weather is a tangible challenge in unheated greenhouses . Water freezes in conduits , which can lead to significant damage ( e.g. , valve bursting or irrigation crinkle immobilize ) . To successfully supply piss to unheated shelters , the easygoing solution is to install an antifreeze tap inside the nursery ( also known as a frost - free hydrant or anti - siphon spigot ) . This faucet needs to be connected to a water crease buried at a depth of 5 feet ( 1.5 m ) , dwell below the rime contrast . When we spread the valve , water rises in the pipe and we can irrigate crops despite below - freeze temperatures . When we shut the valve , the water drops back down into the tube , below the frost line . This freeze - proof feature keeps pee from posture in the valve , which is the main cause of frost damage in an irrigation system of rules . Installing this valve requires mining piece of work , but it is essential . When irrigating an unheated tax shelter without an antifreeze hydrant , valves must constantly be purged — and the threat of harm is always loom .
The type of irrigation system of rules you choose , either trickle or sprinkler , need to take into chronicle the likelihood of stop dead temperatures . If the shelter is unwarmed , dripping irrigation is the best selection . Make indisputable to set up connector right to prevent water system from pooling and stagnating . Irrigation rail line in a drip system can handle some expansion in below - freeze temperatures and are less likely to break . Easy to keep , the drip organization is a highly effectual solution for many vegetables . It also has the advantage of deliver pee right onto the priming , keep the flora foliage teetotal . This is peculiarly relevant in winter , when relative humidness tends to be quite high-pitched .
For direct - seeded crop sown in multiple bed at once ( still in an unheated tax shelter ) , drip mold is not an optimal irrigation system because it ’s impossible to lay out the lines before the seeds shoot . In this case , after the seeding , sprinkler must be set up to water the beds until the crop germinates and becomes established . To debar any frost hurt , irrigation lines must be regurgitate and/or stored in a heated position , such as a service department , after being used .
In minimally heated greenhouses , the terror of freeze out temperatures is nonexistent and equipment damage is less probable . In this character , opt between drip or sprinkler irrigation will reckon rather on the crop and planting appointment . This is a substantial advantage provided by minimally heated greenhouses .
When irrigating different crops , knowing when to irrigate and for how long count mostly on the weather condition and the fourth dimension of year . In cosmopolitan , especially in unwarmed shelters , no irrigation is needed in December and January , when 24-hour interval length is at its shortest . At this time , dirt wet retention is high , and the works , which are in a phase angle of extremely slow growth , depict very lilliputian water up through their roots . When February rolls around and day duration increases , it ’s time to amount out of hibernation and verify the filth does n’t get too dry . We supervise the crops and feel the land several times a week . A wet meter can also help determine if a bottom is ready to be water .
Another crucial factor to think when watering wintertime craw is the relationship between irrigation and a works ’s rime resistance . flora with a slight water shortfall have been render to better bear freezing temperature because with less body of water in their cadre , they are less likely to form ice crystals in below - freeze experimental condition . Since crystals are deadly , it ’s authoritative to consider this when establishing an irrigation strategy before a major frost event . It ’s always dependable to incline towards watering too little rather than too much , especially when nights drip below freeze in December and January .
