When to Water
Here are my thoughts.
It is recommended to water in the morning as it helps the plants absorb the water better and allows the water droplets to not just sit on the plant possibly creating disease or fungus as suggested at night. Afternoons the water has more of a chance of evaporating due to it being hotter in the day.
Morning, afternoon, or night?
Morning time can be anytime before noon or before it gets too hot. In Edmonton it does not get really hot too earlier in the day. Sometimes we have a warm spell, and it may be hot for a week in the summer. Morning time may be earlier then and watering your plants before it gets too hot helps. On cooler days like it normally is during the summer, then water when you can in the morning.
I would say the same with evening water, it depends on how hot it is and if you have watered them once already. In fact, sometimes during a hot spell I will water twice a day. In Edmonton it stays bright till later during the summer which makes taking a walk and watering your plants at night a nice nigh time activity. Try to water them early enough so the water does not stay on their leaves and possibly create fungus.
Water enough?
Edmonton’s climate is a little drier so whether you water in the morning afternoon or evening does not matter as much if you do not water well. What does that mean? It means to water directly over the root of each plant, so the root gets the most water. When we water, we tend to spray the plants and generally water the area. This can create mildew on the leaves and not allow the water to get to the roots. The results are your plant does not get enough water whether it is morning, afternoon, or night. Plants require approximately an inch or so each week.
When I water plants, particularly annuals (that do not have much root development in the soil), I water each plant and count to 10 each time. It usually takes a couple of weeks before they are established, and I can count to 5 when I water them. Once the plant is established, I can water more generously but try to make sure my plants have a good soil watering at least once every 3 days.
Seeds
Seeds I am incredibly careful not to disturb the seed and try to soak the dirt gently or use an exceptionally fine spray. Seeds do not want to sit in water but do not want to dry out either.
Once seedlings start to grow, they will let you know how much water they need.
Vegetables
Vegetables in a container that I plant in my garden, particularly tomatoes, I treat like annuals but find I do not need to water them as long. Maybe I count to 5 or 6. However, most vegetables we plant in Edmonton will need a healthy dose or regular water. Potatoes need water until the vegetation starts turning yellow and then it is less.
Mulching
What does this have to do with watering?
If you mulch you can help the soil to retain its moisture especially in hot dry areas for long periods of the day. It also helps reduce soil erosion. Even with your seedlings you can put grass savings on the dirt to protect them from getting burnt by the sun. Types of mulch are wood chips, leaves, grass, shavings and even shredded paper.
A good general article on types of mulches.
https://www.gardeningknowhow.com/garden-how-to/mulch/choosing-garden-mulch.htm
Weather
The weather will affect how much you water. If its cooler out, rains for days, too hot, all of this will affect your watering. Remember you are in a relationship with your plants and the weather, type of plant, soil conditions, depth of soil and mulching all affect the water the plant will need. Edmonton weather is not so much hot as it is dry, drying up the ground quick especially if it is not mulched.
The rain does not seem to tell the time of day. Just because it rains it may not mean the plants have had enough water, always check. There is always exceptions to the rule. I have a plant I water the leaves as well and it has never been healthier. It keeps the bugs off of it. Sometimes I have been known to relive some of the dry heat off my plants by watering in the afternoon as well as morning or evening. I see it as giving them a drink during a hot summer day rather than a soaking. Watch your plant and let them teach you what they need.
My recommendations:
Know your plants and how much water they need (new plants, seeding and some perennials need more)
Water the soil close to the root to get the water as close to the roots as possible at least once every 2 or 3 days.
Watch the weather for signs on how much to water.
Use a counting system on new plants until they get established to ensure the roots get the water and each one gets the same amount.
Take your time, enjoy watering, and do not rush.
Water seeds as gently as possible so as not to disturb the seed.
Look for disease and mildew on your leaves or fruit.
Mulch to help retain moisture.
Morning, afternoon, or evening have their advantages and disadvantages for the plant and for you. Choose what works best for the plant, the weather and yourself.
Here is one of my favorite sites with some simple and good information about watering.
https://www.gardeningknowhow.com/edible/vegetables/vgen/water-plants-vegetable-garden.htm
When to Water
By Southern Living Plants Staff August 6, 2019
We all love drought resistant plants!
We all love drought-resistant plants that simply go limp when dehydrated and then spruce right up when given water. Not only do they physically tell us they need water, but there doesn’t seem to be any consequences for waiting until the last minute either.
Unfortunately, not all plants are so obvious about needing water, and water does play a significant role in the health of plants. Under and overwatering plants can create weak roots, cause foliage to change to undesirable colors and blooms to drop, or prevent blooming altogether.
How do we know when to water before it’s too late?
Though different Southern Living® Plant Collection varieties have different needs, time of day, temperature, soil, and age are major factors in determining when and how often your plants need water.
The best time to water plants is in the morning or evening.
Watering in the morning prepares the plant for the day to come and watering in the evening cools it off. More importantly, watering at these times actually helps the plant retain water. 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. At night, water tends to rest in the soil, around the roots, and on the foliage, which encourages rot, fungal growth, and insects.
Heat and dry soil are always indicators that a plant needs more water
When the sun is out and the temperature is high, your plants are baking right along with you. Nothing is better than some refreshing water and your plants couldn’t agree more. If the soil is dry, the plant is already dehydrated, and you need to water more often to ensure healthy growth. Ideally, the soil should be moist and well-drained.
A plant’s age also helps you know when to water
“Age” refers to the length of the plant’s life and also to the length of time the plant has maintained residence in your yard. The young and the newly planted need more water to establish a healthy root system. Shallow and fragile roots require additional water to promote root strength and expansion. Mature plants don’t need water as often; instead, they need a larger amount at one time so that the established roots can thrive deep in the ground.
When there are so many plant varieties, it can be difficult knowing when to water, but watch for the tell-tale signs. If you see a general decline in the health of your plant, if the leaves are yellowing or browning, the flowers aren’t blooming, or the petals are dropping, the plant could be getting too little or too much water. Most of all, remember to reserve a little extra time in the morning for premium watering – your day may be that much healthier too!