In plants, water passes through the stomata, which are small pores in the epidermis of leaves, stems and other organs. During the day, the stomates open to allow water to be taken from the plant's roots, then trade that water with carbon dioxide so that photosynthesis (and thus, plant growth) can occur.
Certain crops are more susceptible to bacteria or fungus if they stay wet for too long. And, Nicolai said, he knows some farmers who aren't as comfortable with complicated machinery running while they're asleep in their bed.
Night-time humidity is higher, which also reduces evaporation. There is no sun, so solar radiation does not contribute to water evaporation.
Watering in the morning conserves water by allowing it to soak into the ground without evaporating. Avoid watering at night because foliage will stay wet all night long leading to disease problems. Watering during the middle of the day also has its problems.
Water applied as irrigation allows for crop production in arid regions and supplements soil moisture in humid regions when growing season precipitation is insufficient. Irrigation has enhanced both the productivity and profitability of the agricultural sector.
The bulk of irrigation research recommends irrigating row crops such as grain or cotton when the MAD approaches 50%. For vegetable crops, the MAD is usually set at 40% or less, because they are more sensitive to water stress.
If your plants are in the ground (versus a pot), the general rule is that plants need one inch of water per week. However, this does NOT mean watering one time per week. That doesn't usually do the job. Plants do best when watered deeply about three times a week, factoring in the rain.
Current assumptions are that nighttime irrigation is more efficient due to less evaporative demand (more humidity, lower temperature, no solar radiation, less wind. etc). However, watering in the afternoon could be more efficient because it coincides with peak photosynthesis and has microclimate cooling effects.
According to lawn care experts, the best time to water grass is in the early morning, ideally before 10am. During this time, the temperature outside is still relatively cool, and the wind and sun are less intense.
Early morning (5:00 to 9:00 am) is the best time to water the garden when using a sprinkler, garden hose, or any other device that wets the plant foliage. When watering is completed, the plant foliage dries quickly. The rapid drying of plant foliage helps guard against the development of fungal diseases.
Historically, farms all had cows to milk, and it's most comfortable for the cows to get milked at evenly spaced times each day, which means on a two a day milking cycle, you find farmers milk early (say 5am and 5pm) to eat dinner at a normal-ish time and see their kids before bedtime.
Every crop needs to be watered each day until fully grown. An immature crop that goes unwatered on any day does not die, but it does not grow either. Mature crops that produce multiple harvests also require daily watering. Crops planted outside do not need to be watered on days in which it rains.
Soil Sensors
A more recent development is sensors that measure rainfall by sound. Sensors range from simple to more complex. They may be electric or solar-powered. Soil sensors can network with irrigation pumps, using wires or wirelessly, and the sensors tell the pumps when to water the crops.
If you water in the afternoon, especially during summer, the heat and sun are at their peak and the plant's water will evaporate instead of absorbing into the soil and roots. Morning watering is actually preferable to evening watering as the plant has time to dry before the sun goes down.
Farming doesn't stop just because the sun sets. Across the West, a variety of crops are harvested at night, such as wine grapes, tomatoes, onions, garlic, and corn.
Irrigation water can come from groundwater, through springs or wells, surface water, through rivers, lakes, or reservoirs, or even other sources, such as treated wastewater or desalinated water. As a result, it is critical that farmers protect their agricultural water source to minimize the potential for contamination.
Avoid watering grass on a hot afternoon when it's 95 degrees or higher. The best time to water grass is at dawn or in the early evening. Water deeply three times a week instead of a little water daily. Test whether your sprinkler system is watering your lawn evenly.
Between irrigation and natural rainfall, your grass should receive between 1 and 1.5 inches of water each week during the summer. Water deeply every other day for the best results.
Most lawns need to be watered no more than three days a week in the spring as well as in the summer and two days a week in the fall. This watering schedule is recommended under normal water supply conditions.
The best time of day to water a lawn is early morning, between 4:00 and 8:00 a.m. The cooler temperatures and minimal wind allow water to soak deeply into the soil without much evaporation. Also, during this window, there's not as much demand for water on municipal systems, which can impact pressure.
It is ideal to water lawns about one inch of water per week. To determine how long you need to water to get one inch, place a plastic container in your yard and set a timer. On average, it will take 30 minutes to get a half inch of water. So, 20 minutes, three times per week will give a lawn about an inch of water.
Best time of day to water the lawn
Always water your lawn in the early morning, between 4 a.m. and 10 a.m. In the morning, temperatures are still cool, and your grass will have time to absorb the water before it evaporates under the hot sun of midday. Don't water your lawn at night or in the evening.
The amount of water required to cover one acre to a depth of one foot. This is equivalent to 43,560 cubic feet or 325,851 gallons. acres have more than one water source. Source: USDA NASS 2018 Irrigation and Water Management Survey (2017 Census of Agriculture).
California's Farmers Are Pumping Too Much Water From Their Wells California's farmers are pumping vast amounts of water from underground aquifers this year to make up for water they can't get from rivers. It's unsustainable, and the state is moving to stop it.