How much water does my garden need?
The UK is known for its unpredictable weather patterns, with some areas receiving significant rainfall throughout the year. However, despite frequent showers, summer can bring long dry spells and heatwaves, which place increased pressure on gardeners to water their plants and lawns. During these hot periods, the demand for water spikes and there are often hose-pipe bans.
A water butt offers a sustainable solution to this issue. It allows you to capture and store rainwater, which can then be used to water your garden during dry spells, helping you save money on your water bill and reduce your reliance on mains water. In this blog, we will take an example of a standard UK garden and find some answers to the question of how much water we really need.
High Rainfall, but Low Summer Rain
The UK is fortunate to experience relatively high rainfall compared to many other countries. In fact, the average UK rainfall is around 1,100mm per year but it is not evenly distributed throughout the year. We gardeners are beginning to face the challenge of keeping plants hydrated during summer, especially when heavy showers are few and far between.
Heatwaves or drier-than-average conditions bring in the threat of hose-pipe bans. While there may still be occasional rain, it often isn’t enough to keep gardens adequately hydrated, let alone reservoirs topped-up. During the driest months in the UK, particularly in the southeast, rainfall totals are as low as 50mm per month— far from the ideal 150mm required to keep the garden properly watered.
This is where having a water butt becomes invaluable. It allows you to capture and store rainwater as a reserve, ready for when the dry periods arrive.
How Much Water Does Your Garden Need?
The amount of water your garden requires depends on the types of plants and their individual needs. According to the Gardeners' World UK website, here’s an estimate of how much water different areas of the garden require:
1. Lawns: Lawns can require a substantial amount of water, especially during dry spells. According to the Royal Horticultural Society (RHS), a lawn typically needs around 25-30 litres per square metre per week during dry periods. Given that a lawn has a large surface area, this can quickly add up to significant amounts of water over the course of a summer.
2. Vegetable Gardens: Vegetables like tomatoes, cucumbers, and beans are particularly thirsty. RHS experts recommend that vegetable gardens need around 30-50 litres per square metre per week during a dry summer. This can be especially important for gardeners growing crops that require consistent moisture, as drought stress can severely impact yields.
3. Flower Borders and Shrubs: Flower borders and shrubs also require water to thrive in hot weather, although they generally need less than vegetables. On average, flower beds need about 20-25 litres per square metre per week.
A Typical Garden Watering Estimate
A typical UK garden is 188m² but is made up of growing areas around 50m² (lawns, borders etc). Here’s how the water requirements break down for a typical summer dry spell.
- Lawn (30m²): 750 litres per week
- Flower Borders (20m²): 600 litres per week
Total water requirement per week: 1,350 litres, that's a staggering 5,400 litres per month!
Consider that these values are for a typical garden. Sizes vary greatly and your garden may need substantially more.
It's clear that we need to approach our watering needs intelligently, as it's just not possible for every house to use this amount of water, not only because of cost but simply because during dry spells there isn't enough water for everyone.
Read some of our other water related blogs to learn about the drawbacks of tap water, the benefits of rain water and how we gardener's can meet the challenges of water shortages.