Updated: Apr 5, 2021
This year on World Water Day, 22 March, I posted on social media about the importance of understanding the value of water as gardeners and I think this subject is well worth discussing further.
We are all in one way or another experiencing the consequences of climate change and it’s a warning sign for us to start reconsidering many of our gardening practises. Extreme whether events mean that a regular supply of water is becoming less dependable. As gardeners many of us know how to be frugal and I think we need to adopt that frugality in our water usage.
Let me begin by saying that using tap water on your garden should be a last resort, and only when all other water saving techniques have failed you. And the reasons for this are three fold;
It’s no good for our plants, after it has gone through the purification process all the nutrients the plants need are gone, rainwater is best
It requires large amounts of energy to purify and transport tap water to our homes, adding a large carbon footprint to your home grown veg
It’s wasteful and if you follow some of these water saving techniques, you won’t need to use tap water in your garden
Technique 1 - Harvesting Rainwater
The two things I encourage every gardener to do is make their own compost and harvest rain water. These two things are key and vital to help you develop your garden into a productive space. Harvesting rainwater is crucial in every garden. If your house has a down pipe then you can install a water butt. You can buy down pipe adaptors which are really easy to install and hook up.
So hook up as many water butts as you can, if you have a shed or greenhouse then install guttering and add a water butt.
Just as important and if possible, add an overflow reservoir to you water butt.
Add troughs around your garden or plot, they don’t have to be pretty it can be a simple as a bin with an upturned lid with some holes in the top, this will help prevent debris from falling into the water, you’ll be surprised how much rainfall it will capture. Harvesting rainwater not only helps preserve this precious element, it also saves you money and is better for your plants health and productivity.
Technique 2 - Mulch
One of the biggest ways in which water is wasted in the garden is through soil surface evaporation. Adding a layer of mulch to your soil surface helps to reduce this and lock in all the moisture. It can take a bit of time and work when you are first starting out but you will be rewarded for your efforts. Mulch not only significantly reduces the amount of watering needed but it also conditions the soil. Adding a handful around your plants after plating provides much needed nutrients as well as locking in moisture. Mulch will also help with surface runoff, which I will come back to. You can use compost, leaf mould, coir and even grass clippings (keeping the layer to 1cm). Strulch is another option. A fantastic mulch developed in the UK. It’s perfect for organic gardening with added minerals to help deter slugs and snails, just be sure to reuse the plastic bag!
Technique 3 - Green Manure
Protecting your soils surface during the Autumn/Winter months is important. Soil left bare can develop an impermeable crust on the surface, therefore growing a green manure not only helps minimise the chance of surface runoff in Spring/Summer but even adds additional nutrients to the soil when left to die back. Others such as, alfalfa have a deep tap root that loosen any hard layers, which will subsequently help your main crop root more deeply, giving them access to a greater volume of stored water. All of this is very beneficial when you come to sow your crops in Spring. Green manures also help provide a much needed food source to our pollinators when pollen is scarce. If you’re not that into green manure you could also try crop rotation and keeping your beds full through the year, there are some wonderful hardy vegetables you can continue to grow in your beds with some added protection. But this can also be achieved by using a mulch.
Technique 4 - What you grow
Take stock of the type of plants that you are trying to grow and understand that you need to harvest the rainwater for those plants. So make life a little easier and choose plants that don’t require much water. We have access to and are rather spoilt by the choice of plants we can grow. We have the freedom to grow many exotic plants, so do a little research and maybe try experimenting with drought tolerant plants, such as cacti, alpines & even grasses. Move towards growing perennials rather than annuals, many perennials have the chance to develop a much more extensive root system so are more resilient and require relatively little watering. In addition to the plants themselves, think about using fungi when planting. Mycorrhizal fungi attach themselves to the plants roots and grow outward feeding back to the host plant any extra water and nutrients which would otherwise be too far for the hosts roots to reach, now there’s some symbiosis at work!
Technique 5 - Hose Vs Can
I water with a watering can, in fact I have several of them dotted around the garden. I find I can monitor the amount of water I’m using this way, with a hose you just don’t know. However if you prefer a hose I suggest hooking it up to your water butt and measure the level of water before and after watering your plants, you will be shocked at how much you can get through with a hose. With a watering can I can be more precise, directing the water to the areas it’s needed most. And when I use the rose attachment I can cover a larger surface area so it’s not that more time consuming than using a hose. Also watering cans are a good way to distribute liquid feeds, home-made of course.
I water less often but in larger doses. Watering shallowly means you will need to do it more frequently and you won’t be reaching all the roots. I avoid watering plants from above, this is partly because I have many houseplants so that technique doesn’t work well indoors and outdoors all you are doing is watering the leaves of the plant which means it isn’t reaching the roots where it’s needed. It also can cause leaf scorch on a hot summer day and will increase the likelihood of diseases. My father in-law told me that when he waters his plants he likes to imitate the rain, I can see the rationale behind this but no, STOP IT!
Technique 6 - Irrigation
There are many irrigation systems out there and it is a timesaver and providing you are using it at the correct time and for the duration that is necessary for the plants, it can actually save water too. But do your research and try to find ones that hook up to your water butt and run on solar energy.
Some of the options out in the market place include grow bag irrigation systems, perfect for your greenhouse tomatoes. Micro irrigation kits which you buy all the parts separately and make up your own system to suit your requirements, these are perfect for container growing or for when you fly off on holiday (remember those?). Self watering pots and soaker hoses are other options and of course capillary matting is perfect for keeping your smaller pots ticking over. And for those hanging basket addicts out there, you can now buy flower wells which are a hidden reservoir that sits in the bottom of the basket, reducing the need to water everyday.
There are some really innovative ways of getting the water exactly where it’s needed, like adding a watering pipe alongside the plant when planting and instead of watering the surface, you water down the pipe, which gets the water straight to the roots.
Ollas are an old technique using soil moisture tension. This is one of my favourite techniques and I’d love to be able to stock these on the site one day, not only are they beautiful but they are functional too and dramatically reduce the amount of water usage. I believe they were first used as irrigation for Olive trees. They are an unglazed ceramic vessel, often with long necks and a wide base, which you bury in your beds and add water into the vessel. Through soil moisture tension, when the soil around the olla is dry the water is pulled out through the pores, once the soil is sufficiently wet the tension reduces and water remains in the olla.
They have a very rich history and I recommend looking them up if you are unfamiliar. You can even create your own using terracotta pots, which I’m going to attempt this year in my garden, so I will keep you posted.
Technique 7 - Time
The most beneficial time to water your plants is first thing in the morning, this gives the plants optimal time to absorb the water before the sun is too intense. You can also water early evening but be mindful these are the conditions that attract slugs and snails.
If you water when it’s too warm, like mid-day you loose a huge amount of water through evaporation. And if you can water on an overcast day rather than a sunny day this too will avoid water evaporation. It sounds counter intuitive because you think the plants are going to need it most on sunny days but if you water on an overcast day the moisture will remain there present in the soil for them to draw upon.
Technique 8 - Be selective
By mid-summer your water butt’s and reservoirs are going to be running on empty so do be diligent in checking what needs to be watered, don’t just assume because it hasn’t rained for a couple of days that your plants need watering. Do the check, use your finger to check the top 2-3cm of soil, if it’s dry then water.
Prioritise your watering and ration it out to those who need it most. Vegetables that produce pods or fruits, water less before fruiting to reduce leafy growth and then increase watering as it begins to flower and fruits set. The older the plant the less frequently they will need watering. Seedlings sown direct should be top of your list, followed by leafy salads. There is a handy trick to seed sowing which does help reduce watering. Prior to sowing the seed in the soil, water the drill or holes that you are sowing into, this moisture will help get the seeds going far better than watering from above once they are sown. After a couple of days (if it hasn’t rained) you can water from above, this will help prevent soil capping which can prevent the seed from germinating.
Containers usually dry out faster than raised beds so be sure to check your containers regularly.
The beauty of gardening is that you learn new techniques and even revisit some old techniques all the time. But it’s important that we continue to educate ourselves, learn and adapt to our current climate, wherever we are in the world.
Just 4% of global freshwater is used domestically and a whopping 72% is used by the agriculture and cotton industry to feed and clothe us. We are constantly encouraged to take shorter showers and turn the tap off when brushing our teeth but in truth reducing your meat intake can have a much higher impact than any other ‘water saving’ technique you adopt.
Despite how we might feel at having an endless supply of clean water at the turn of a tap, we should not be taking this resource for granted because it is finite, if we don’t use it wisely we will run out. If you take away just one thing from this discussion I hope it’s to install a water butt because harvesting rainwater is like purity from the clouds and your plants will thank you for it.