A DRY TOPIC? | How to water your garden
Bright sunshine, beach weather and long balmy nights sitting outside – it's a summer right out of a picture book.
As lovely as it all is though, there's just one thing missing: water. Prolonged (extremely) dry spells create an enormous amount of extra work for gardeners and farmers. For the latter, it can threaten their livelihood when crops suffer.
Photo: Janina Laszlo
It has – phew – rained a little here from time to time. For me, that's sufficient because I brazenly claim that I don't really water my garden (except for pots and anything freshly-planted, of course) and that I've taught my plants to grow strong, deep roots.
But what do you do if it really hasn't rained in weeks, the grass is a crispy yellow carpet, the trees are shedding their leaves and the flowers are oh-so-sadly hanging their heads? I asked an expert gardener, Barbara Gerlach, about what it really means to "water the right way".
Hello Barbara! So how are things looking in your garden right now?
Where I am, it hasn't properly rained in months and it's also been really sunny and windy. The plants are struggling.
So, how do you handle a drought like this?
I could've done a lot to help myself and my garden if I'd just paid more attention to location when planting. What I mean by that is selecting plants according to the type and quality of the soil and the hours of sunlight and then putting them in the right places. But, of course, I want to have loads of different plants in my garden, so I have to vary the way I water them accordingly.
Photo: Raphaela Gerlach
What does that look like?
The most important rule is: it's better to water once a week really intensely than a bit every evening.
And why is that better?
Because it makes the plants learn to fend for themselves. If I only water them a bit every evening, I'll only reach the top layer of soil. This means that the roots will become lazy and stay near the top. However, you can train them to grow further down where they can reach water for themselves. Then you won't have to water them so often.
How much do I need to water them if I'm only doing it once a week?
That depends on the plant because it all comes down to the size of the root ball, which is the part you want to reach. There's a little trick using the pots in which you bought (as an example) your perennial: those pots are usually around 10cm (4") high, which means that the water needs to soak 10cm (4") deep into the soil to reach the end of the root ball. For woody plants or trees, it's obviously much deeper.
That sounds like a lot of water. And work!
Not necessarily. For larger areas, I use a sprinkler that has a timer and allows me to adjust the height and direction. I set it for 90 to 120 minutes and I can get exactly the right amount of water, precisely where I want it to be. Bear in mind thought that that's based on the soil properties where I live, so it will be different for everybody.
If I don't have a lot of experience with this method, how will I know how deep the water has sunk into the soil?
It's really easy: if I've watered it in the evening, I'll wait until the next morning, take my spade, stick it deep into the soil and then pull it towards me. That way I can see how damp it is and assess whether it's enough. As a little side note – I only use the sprinkler method for my flower beds when it's really dry like it is right now. Usually, I only water my new perennials with the hose or a watering can. But please never water from above! Instead, aim the water directly on the stem(s), right at the bottom of the plants.
Photo: Barbara Gerlach
Do you have a trick on how to figure out the right amount of water when I use a hose?
I do, and it's a little test: use your hose – on the same setting you use for watering – to fill a 10L (2 gallon) watering can with water and count how many seconds it takes. For me, that’s around 50 seconds and means I need this much time to give a 1sqm (10ft2) area 10L (2 gallons) of water, which is the equivalent of around 10ml (0.3 fl oz) of rain (during this time a surface of 1sqm – or 10 square feet – receives the equivalent of around 10ml or 0.3 fl oz). That's not a lot, it's really only enough for the weeds, and that's why I prefer to water more targeted using a watering can.
Around freshly planted trees and woody plants, I use a watering ring so the water can penetrate deep into the soil rather than run off the surface. Just make sure the watering ring isn't too big so the water can sink through the loose soil all the way down to the root ball rather than drain away. Depending on the size of the plant, you can fit around 50L (11 gallons) of water into the ring.
And the same rule goes for this method: it's better to water generously once a week than only a little bit three times a week. For young trees, that should be around 80 – 100L (17.5 – 22 gallons) a week. Watering bags are particularly good for this. You fill them up once and the water is then slowly released into the soil through a membrane.
Is there anything else to consider? Who wins – garden hose or watering can?
The most important thing is having the right attachment. Those hose spray guns you find everywhere aren't great for watering. The fine spray means you get almost nothing on the roots; all they do is increase the humidity for a short while. It's better to get a hose with a watering rod and spray head, a sprinkler or a classic watering can.
Thank you, Barbara!
Photo: Raphaela Gerlach
Barbara Gerlach has been an expert gardener since 1982. As a garden designer, she lives by the motto "Bringing gardens and people together”. She's all about seeing the garden as living space instead of something that's hard work; of gardening for pleasure, not gardening as a chore.
Raised at a plant nursery, she spent several years travelling, both at home and abroad and has been self-employed for over 30 years.
You can find her on her blog Hortus Vivendi (available in German). And if you'd like to learn more about her consultancy work, have a look at: Aus Lust zum Garten