Plants should be watered when they need it.
How do you know when a plant needs water? An “average” plant needs an inch of water a week. Of course, some plants can get by on much less, while others need to be constantly wet. Knowing the plants in your garden and the different site conditions they require will tell you how much water they need each week.
But that is not how much you should water them. If it has rained recently – or if it’s expected to rain soon – subtract the amount of rainfall from the amount of supplemental water you give your plants. Your local weather forecast may tell you how much rain your area has received lately. Or, you can set an empty tin can in the ground as a simple rain gauge. (You can also use the can to track how much supplemental water you’ve given nearby plants.)
If your plants are watered automatically by a timer system, be sure to turn the system off when the plants have already received enough water from rainfall! Too much water can harm a plant, just the same as too little.
The best time to water plants is in the morning or evening, rather than in the middle of the day. There are two reasons for this.
First, it is usually warmer in the middle of the day, leading to more evaporation. Watering in the cool morning or evening means that more of the water will stay on the soil, rather than moving into the air.
Second, as mentioned in the previous post, plants don’t like their leaves to be wet. In the morning and evening, plants are often wet anyway because of dew. Watering around noon leaves the plants soggy for more of the day, increasing the risk of disease.
One way to water on a schedule is to use a sprinkler system on a timer. The next post will cover a downside of that approach.
We often think of watering plants by pouring water over the top of them. Plants, in fact, don’t like this. They need water at their roots, and can be harmed by water on their leaves, since the dampness can invite mold and other diseases.
But wait. Aren’t plants watered in nature by rain falling on top of them? Yes! Plants have evolved to deal with this by developing various strategies for moving water off their leaves and down to their roots. These strategies also work pretty well when the water is coming from a hose, sprinkler, or watering can, rather than from rain.
But this is a case where we can do better than nature. We can water plants directly at their roots, keeping their leaves dry.
It might seem intuitive to do this by watering at the base of the plant’s stem, but that’s not quite what the plant wants. When plants water themselves by moving rain off their leaves and down to their roots, that water doesn’t end up next to the plant’s stem. It falls along a circle defined by the plant’s outermost leaves. That circle is called the drip line.
Pouring water on the ground in a circle that approximates a plant’s drip line is the most efficient way of putting the water where the plant can absorb it.
The last two posts were on the topic of water. As we move into the hottest part of the year, this post continues that theme, kicking off a five-part series on how to effectively water plants.
“What should you water plants with?” may seem like a silly question. With water, of course! But not all water is the same.
Typically, we water our plants by connecting a hose or sprinkler system to a spigot and drawing from municipal water supplies. This water has chemicals added to it, including chlorine to kill germs and fluoride to promote dental health. Whether these chemicals are actually good for people is still a topic of debate, but it is generally agreed they are not good for plants.
Plants do better with chemical-free rainwater, which also happens to be less expensive than municipal water. All we need to do is catch and store the rain as it arrives. A single rain barrel, connected to a downspout, can collect many gallons of water in a single rainfall.
Over the next few weeks, That Blog will cover other aspects of how to water plants, and then look at plants that may not need to be watered at all.
A watershed is a geographical area in which all the water – from rainfall, snowmelt, garden hoses, or anything else – finds its way to a particular river, creek, or lake.
Everyone lives in a watershed. If you live in Madison, you might be in the watershed of Lake Mendota, Pheasant Branch Creek, or the Upper Sugar River.
Those water bodies, of course, drain into other water bodies. Watersheds are nested inside bigger watersheds. All the watersheds in and around Madison ultimately flow into the Mississippi River, which empties into the Gulf of Mexico.
What this means is that what we put into our water in Madison affects a lot of people who live downstream from us.
Many residents of Madison don’t know that the storm drains along our roads connect directly to our lakes and rivers. The water is not filtered or cleaned along the way. So, if we want to keep our local waterways – and the Mississippi River, and the Gulf of Mexico – clean and safe, we need to be careful about what’s flowing down our streets and driveways.
One reason that Madison sends streetsweepers around is to clean up the leaves, dirt, and other gunk that would otherwise wash down the storm drains. But doing this task with streetsweepers costs taxpayers moneys and consumes fossil fuels. If homeowners swept their curb lines manually – especially before rainstorms – we could keep our rivers and lakes clean in a way that is quieter, cheaper, and more environmentally-friendly.
In plumbing terms, there are three kinds of water. White water is the water that comes in through your faucet and is safe for drinking. Black water is the water that goes out through your toilet, and isn’t safe for anything. And grey water is the water that goes down your drains after being used to wash your dishes, your clothes, or yourself. While you shouldn’t drink it, it’s still good for many other purposes.
For example, some buildings route the greywater that goes down the bathroom sink into the toilet tank. Then, the toilet can be flushed with water that was already used for washing hands, instead of with clean, drinkable water.
Similarly, water that’s been cycled through the dishwasher or washing machine can be used to water plants. Some people have plumbed their houses to drain this water into a rain garden or similar system. The water then gets filtered by the plants, instead of being filtered by a municipal system on the taxpayer’s dime.
Greywater systems are a great way to use resources more efficiently, conserving water and saving money. Unfortunately, they are not legal in many cities, because health departments worry that the slightly-dirty water could transmit disease if drained into yards instead of into pipes.
These fears are largely unfounded. If a greywater system is set up properly, and care is taken to not put toxic soaps or other harmful substances into the system, then recycling greywater is safe for people and the environment.
As water shortages become more severe, greywater systems are likely to become legal in more places. Citizens can ask their elected officials to not delay legalizing this simple way of using resources more wisely.
That Blog turns two years old this week. It is dedicated to explaining why homeowners might want to give up their lawns and instead garden with plants native to their region. Here is a recap of some of those reasons.
Lawns contribute to climate change.
Lawns contribute to species extinctions.
Lawns waste water and other resources.
Lawnmowers are dangerous.
So are pesticides.
Natural yards are easier to maintain.
And they make our lives more joyful.
Natural yards have continued to gain in popularity since That Blog began. This trend seems likely to continue. Since it takes three to five years to establish a natural yard, as it is said, the best time to begin is now.