What are the benefits of using rainwater in your garden

Posted by Callum VP, on September 28, 2020.

Rainwater harvesting has become an increasingly popular option for thousands of households across the UK, transforming the way they live and creating a greener local environment. When you think about it, using rainwater for your garden is a far more natural option than using water sourced from a tap, as it is part of nature’s water cycle. So what are the benefits of using rainwater in your garden? We explain everything you need to know below.

Higher levels of natural acidity

Many gardeners are aware that using soil with pH levels ranging between 5.5 and 6.5 is beneficial to organically grown plants. Rainwater is able to provide the same level of acidity through a natural process, making for healthier soil and better crops as a result. On the other hand, reservoir water is treated with alkaline to stop it from corroding metal pipes, with a pH level that could be as high as 8.5. Meanwhile, greywater – household water discharged from showers, washing machines and bathroom sinks – will have a similar pH level to tap water, although this can increase up to a 10.5 pH level by the time it reaches the garden, depending on the detergents or soaps it was previously mixed with.

100% soft water 

The best thing about reusing rainwater is its natural composition, which makes it better than any other type of water. It does not contain any minerals, salts or treatment chemicals, as well as being free of the types of pharmaceuticals that finds its way into reservoir water via excretion carried in sewers, along with surface water and groundwater. Over time, chemical and salt levels build up in your garden soil to create a harsher environment for plants, which is especially true with potted plants. Rainwater offers pure hydration and makes for a far more healthy option. 

Exposure to nitrate

Plants and crops love macro-nutrients and rainwater is able to supply nitrates, which are the most bio-available form of nitrogen, and plays a key role in plant growth. In order for your plants to thrive they will need to access three essential macro-nutrients that play a central role in helping create vibrant foliage. While there are a number of different types of nitrogen that plants cannot absorb, that is not the case with nitrate, due to its make-up of both oxygen and nitrogen. When rain falls into the soil so does nitrate, which is then absorbed by the plants. 

Added benefit of organic matter

Rainwater that comes from the rooftop into the gutter to be stored in a water tank will also have traces of organic material. This doesn’t mean larger items, as these will be filtered out before reaching the tank, but rather, organic material derived as a result of contact exposure to leaves, bird droppings and pollen. Once stored inside a water tank, these small additional organic elements help to keep the water alive, creating a natural fertiliser-type effect when the water is used for plants in the garden.

Saves on money

One of the biggest benefits enjoyed by gardeners using rainwater in their garden is the money that can be saved. Most notably, storing rainwater will reduce the amount of tap water being used which will be reflected in lower bills. While there is an initial outlay involved with purchasing a water tank and associated equipment (such as a downpipe filter), the savings made over time will ensure it is a worthwhile investment. This is often one of the primary reasons why homeowners look into harvesting rainwater, as it allows them to reduce expenditure, freeing up money that can be used elsewhere around the home.

Helps the local environment

Relying less on tap water will also have a positive effect on the local environment. Water that isn’t being diverted into water systems remains accessible to fish, birds and other forms of wildlife. Along with reducing demand on current water resources, retaining water for use in the garden also lowers the amount of polluted rainwater runoff. In many cases, dirty rainwater travels from storm drains into streams and lakes, which creates its own problems for animals and plants accessing it. Harvesting water means there are less chemicals heading into natural water environments allowing local ecology to thrive. 

What else can rainwater be used for?

As you can see, harvested rainwater offers a number of fantastic benefits for your garden. But stored rainwater can also be used for many other things around the home. This includes washing the car – which will also save you money as you are likely to be far more economical with the amount of water used. Rainwater can also fill ponds and other garden features, as well as for toilet flushing and general household cleaning.