Black truffle: where it grows now and when

The black diamond. It grows hidden under holm oaks and Portuguese oaks on limestone soil, and only the dog knows where.

Black truffles freshly dug from reddish soil at the foot of a holm oak, one of them cut in half
Black truffles freshly unearthed at the foot of a holm oak: black skin covered in small warts and, inside, dark flesh veined with white.

The black truffle (Tuber melanosporum) comes out from November to March, at its best in January, in woods of holm oak, Portuguese oak, downy oak and hazel, mostly in the middle mountains. It is also known as Périgord truffle.

See where it is ready this week

No area is ready for black truffles this week: the forest is still asleep.

The black truffle is the most valuable fungus in Europe and the most secret: it ripens underground, between November and March, on the roots of holm oaks, Portuguese oaks and hazels on stony limestone soils. Without a trained dog there is no way to find it, which is why its grounds are guarded like gold.

Its year is decided by the summer storms and sealed by a wet autumn and a winter without hard frosts. micomapa follows the natural truffle areas, not the plantations, and marks when the limestone soil holds the moisture and the cold the truffle needs to ripen.

What it needs to come out

First, a generous rain, the kind that soaks down to the roots. Then patience: it ripens slowly, underground, for more than a month, as long as the soil holds on to that moisture and stays cold, without freezing. If a frost, too much water or a drying wind comes in between, the flush is aborted and never shows.

Where to look

It comes out in woods of holm oak, Portuguese oak, downy oak and hazel, mostly in the middle mountains, always on limestone soils.

Black truffles by province (in Spanish)

How the forest is doing this week

Forecast of 11 September, updated every day.

How we know when the forest wakes up (in Spanish).