Almond blossom and stone terraces.

The island is a farm

Most visitors see Ibiza from the coast, and the coast is only the edge of it. Behind the beaches the island rises into low hills that have been worked for centuries: almonds on the slopes, olives and carobs on the poorer ground, figs and vines near the houses. The interior is not wilderness with a few farms in it. It is a farm with a few wild places left in it, and the shape of every ridge has been decided by what could be grown there and how the water could be kept.

The farmed land is not flat and it is not continuous. It comes in patches, each one held by a wall, and between the patches there is garriga: rosemary, thyme, wild olive, fan palm, the grey-green scrub that takes over whenever a terrace is abandoned. Look at a hillside from a distance and you can read how far the work went and where it stopped. The pines mark the slopes that were never worth clearing. The straight lines of stone mark the ones that were.

How a terrace holds

Every terrace on Ibiza is a wall and a floor. The wall is built dry, without mortar, from stones cleared off the ground it holds back, and it leans very slightly into the hill so that the weight of the soil pushes it closed rather than open. The floor behind it is shallow. What the wall does is stop the soil from sliding downhill in the first heavy rain of autumn, and slow that rain enough for it to sink in rather than run off.

Nothing in these fields is irrigated. The trees live on what falls between October and April, and the wall is the only piece of water management on the slope. That is why the soil is shallow by design: a deep bed would hold water around the roots for too long. Almonds go higher, where the ground is thinner and dries first. Olives and carobs take the deeper pockets. Fig trees are planted where a wall corner gives them a little shelter and a little extra soil.

• Dry stoneNo mortar is used; the wall leans into the hill and is held by its own weight.
• Shallow soilThe bed behind each wall is thin, so rain sinks in rather than running off.
• GarrigaAbandoned terraces return to rosemary, thyme and wild olive within a few seasons.
• Winter rainNothing is irrigated; the trees live on what falls between October and April.

February in the valleys

Almond trees flower before they leaf, and on Ibiza that usually happens in the first half of February, though the date moves with the weather and a cold January can hold it back a fortnight. The heaviest show is on the flat valley floors in the north and west: the plain around Santa Agnès de Corona, the terraces below Sant Mateu d'Aubarca, the Buscastell valley inland from Sant Antoni de Portmany. The blossom is white with a pink centre, and from a ridge it reads as a haze lying in the hollows.

The blossom is best seen on foot, on the lanes that link the villages, because a car moves through it too quickly and the fields are small. Walk a lane between Santa Agnès and Sant Mateu in the morning and the air is full of bees; hives are brought in for exactly this. The scent is faint and sweet and comes and goes. There is no single viewpoint and no need for one: the whole valley is the thing to look at, and it changes as the light moves.

February is the quietest month of the island year, and the blossom is the main reason to be inland then. The weather is not reliable: there are bright days and there are wet ones, and the same week can give both. What the rain does is make the rest of the interior worth walking, because the garriga is briefly green and the dry walls darken and show their lines. Bring a jacket and boots rather than a plan.

The whole valley is the thing to look at, and it changes as the light moves.

The almond year

Almonds are harvested in late summer, from the end of July into September depending on the variety and the height of the field. The nuts are knocked or shaken from the tree onto nets spread on the ground, then bagged and taken to be dried and cracked. In August the nets under the trees are one of the few signs of work in the interior, and the sound of it carries across a valley. The shell is what the island sells; the kernel inside is what the trees were planted for.

Almond growing once supported a good part of the interior, and the terraces were built for it and for the olives and carobs that shared the slopes. The trade declined as the island's economy turned to visitors, and many fields went back to scrub. The trees that remain are often old, and the walls that hold them are kept up by fewer hands. Buying island almonds is one way to keep the work worth doing, and they are sold in the town markets.

Olives, carob and figs

Olives grow lower than almonds, on ground that holds a little more water and a little less wind, and the trees in the interior are often very old. Some groves have trees planted long before the terraces around them took their present shape. The fruit is picked in winter, from late autumn into January, by hand or with small rakes onto nets. Island oil is made in small quantities, and it is dark and peppery.

The carob tree is the one that looks most at home here: broad, dark, and tolerant of thin soil and heat. Its pods ripen in late summer and were once used as fodder and as a sweetener, and carob flour is still sold. Figs grow at the edges of the terraces, where a wall gives shelter, and are eaten fresh in late summer or dried on mats in the sun. Neither crop asks for much, and that is the point of both of them.

• AlmondFlowers in February and gives nuts that are harvested in late summer.
• OlivePlanted lower, on deeper ground; picked in winter and pressed for oil.
• CarobDark pods ripen in late summer for fodder, syrup and flour.
• FigGrown at terrace edges, eaten fresh or dried on mats in the sun.

Villages of the interior

Most of the interior villages are a church, a square, a few houses and not much else. Sant Mateu d'Aubarca, Santa Agnès de Corona, Sant Miquel de Balansat, Sant Llorenç de Balàfia and Sant Joan de Labritja all follow the same pattern: a whitewashed church with thick walls and a small porch, a square with a tree and a bench, and a handful of streets that end in fields. They are working places rather than sights, and a short stop is usually enough.

The rural churches were built solid rather than tall: thick walls, small windows, a porch, and in a few cases a defence tower added when the coast was raided from the sea. Inside they are plain and cool, and sometimes open in daylight, though not on a fixed timetable. Around them the village has kept its shape because there was never a reason to change it. The largest building is usually the church, and the second is usually a house that has stood there as long.

Read the walls

Look closer at a terrace and there is more than a wall. Dry stone was used for shelters too, small rooms with a roof of flat stones stepped inwards to a closed top, built to store tools, to shelter from rain or to cover a well. There are cisterns cut into the rock or built under a terrace to catch rainwater, and wells with a wooden frame and a bucket. Some walls have a ramp of steps built into them, so a donkey could reach the upper field.

The details tell you what a field was for. A wall built from large blocks with a careful face is older work, and a wall of smaller stones thrown up quickly is a repair. A terrace with a cistern was a field someone expected to keep working for a long time. One with nothing but a gap for a gate was for dry crops and a long walk. None of this is signposted and none of it needs to be. It reads fine from the path.

• BarracaA dry-stone shelter with a stepped roof, used for tools or over a well.
• AljubA cistern cut into rock or built under a terrace to hold rainwater.
• SíniaA well with a frame, a wheel and a bucket, worked by hand or animal.
• CapstonesThe top stones are sometimes set on edge so rain runs off the face.

Walking the farm tracks

The interior is crossed by old tracks, camins, many of them public rights of way. They pass between fields rather than through them, and the rule is simple: stay on the track. A terrace wall is a boundary and a piece of infrastructure at the same time, and climbing over it loosens stones that took a season to place. Leave gates as you find them, open or closed, because a gate left wrong becomes a farmer's problem within the hour.

Distances inland are short and the walking is slower than the map suggests, because the tracks climb and turn and there is little shade. Carry more water than you think you need: the interior is dry even in February and there are few taps between villages. Phone signal is patchy in the valleys. Start early, plan a loop that ends at a village, and check the route network of the Consell Insular d'Eivissa if you want a signposted line rather than a lane of your own.