The Tuscan garden that drinks only rain
Borgo Pignano waters its gardens with rain held on the slope it fell on. The method is old, it costs very little, and it works on a garden of any size.
Borgo Pignano is an eighteenth-century villa and a small hamlet on a limestone hill above Volterra, in Tuscany. Both were emptied after the two wars. Michael Moritz and Harriet Heyman bought the estate in the 2000s and rebuilt it with local stone and local stonemasons. The seven hundred and fifty acres around it are certified organic, and the kitchens are fed mostly from the farm. More on how I read a food like that in the Food area.
The gardens are watered with rain, caught and held on the slope in swales. According to Visit Tuscany it was the first time this had been done in Tuscany.
The ditch across the hill
A swale is a shallow ditch dug along the contour of a hill, level the whole way. Rain runs into it, stops, and soaks down into the ground instead of running off the slope and away. The garden then draws on that water for weeks after the rain has gone.
Three things make it work, and none of them need an estate:
- Watch the ground during the next heavy rain. Where the water runs is where the swale goes, straight across that line.
- Dig level, not downhill. A ditch with any fall in it becomes a drain and sends the water away. A level one holds it.
- Plant on the downhill lip, in the soil you dug out. That is where the water sits.
A water butt on a downpipe does the small version of the same thing, for pots and beds. More of that kind of thing is in the Hearth.
Rain is the only water that has not been through a pipe, a tank or a treatment works on its way to you.
That is why I like it in a garden. What comes out of the tap indoors is a separate question, and the first thing I check in a room.
| What it is | A shallow ditch dug along the contour of a slope, level the whole way, so rain soaks in instead of running off. |
|---|---|
| Where it goes | Straight across the line the water takes in heavy rain. Watch the ground during the next storm and it shows you. |
| Level, not sloped | Any fall along its length turns it into a drain. Check with a spirit level on a long board, or a length of clear hose filled with water. |
| Size for a garden | Typically ankle to knee deep and 30 to 60cm wide, with a flat bottom. Steeper ground and heavier rain want more. |
| The spoil | Heaped along the downhill lip as a low mound, the berm. It holds the water back and it is the best planting ground on the slope. |
| What to plant | On the berm. Fruit trees, shrubs and deep-rooted perennials reach the water the swale is holding. |
| Where not to | Very steep or unstable ground, and anywhere the held water would sit against a wall or a foundation. Keep them well downhill of buildings. |
| The small version | A water butt on a downpipe, for pots and beds. |
The short answers
The same thing again, in the order people ask it.
What is a swale?
A shallow ditch dug along the contour of a hill, level the whole way along. Rain runs into it, stops, and soaks down into the ground instead of running off the slope. It stores water in the soil rather than in a tank.
How do you find where a swale should go?
Watch the ground during the next heavy rain. Where the water runs is where the swale goes, cut straight across that line. The rain follows the contour already, so it shows you more reliably than measuring does.
Should a swale be level?
Level along its whole length. A ditch with any fall in it becomes a drain and carries the water away, which is the opposite of the point. A spirit level on a long straight board, or a length of clear hose filled with water, is enough to check it.
How deep should a garden swale be?
Typically ankle to knee deep and about 30 to 60 centimetres wide, with a flat bottom. What matters is whether it can hold the water that arrives in one storm without spilling over the low end.
What do you do with the soil you dig out?
Heap it along the downhill lip as a low mound, called a berm. It holds the water back, and it is the best planting ground on the whole slope, because the water sits just underneath it.
What do you plant on a swale?
On the berm, in the soil you dug out. Fruit trees, shrubs and deep-rooted perennials do particularly well, since their roots reach the water the swale is holding.
Where is a swale a bad idea?
On a very steep slope, on unstable or slipping ground, or anywhere the held water would sit against a house wall or a foundation. Keep them well downhill of buildings. On flat ground a water butt does the job instead.
What is the small version?
A water butt on a downpipe. It catches the rain off the roof and holds it for pots and beds, which is the same idea at the size of a courtyard or a balcony. What a butt catches, what size to get and what to do with it in frost is in the hotel that runs on rain.
Is rainwater better for plants than tap water?
Plants generally do better on rain. It is soft, it carries no chlorine, and it has not been through a pipe, a tank or a treatment works on its way to them. Tap water is treated for people rather than for plants. A garden watered the same way, from a mountain stream by gravity, is in the garden that came before the guest rooms.
Can you drink rainwater caught off a roof?
Roof-caught rain is garden water. It picks up whatever is on the roof and in the gutter. Drinking water is a separate question with its own answer, which is to find out what is in your tap and filter for that.
The property. Borgo Pignano, above Volterra, Tuscany. Rainwater harvesting, reed-bed water treatment, woodchip boilers and local sourcing are described on borgopignano.com/sustainability, and the certified organic farm on borgopignano.com/our-farm. The eighteenth-century villa and hamlet, the seven hundred and fifty acres, the Moritz and Heyman restoration, and the swales being a first in Tuscany are reported by Citizen Femme and Visit Tuscany.
Reuse. Quote any part of this page with a link back to it. Educational purposes only, and not a substitute for medical advice.