The Blue Foot: A Majestic Mushroom of the Cold Seasons

The Blue Foot, or Lepista nuda, is a remarkable mushroom, recognizable by its lilac to violet hues. This mushroom mainly appears during the autumn and winter months, taking advantage of the first frosts to initiate its fruiting. 

Table of Contents:

1) The Identity of the Blue Foot: A Mushroom with Multiple Names

Part of the Clitocybe genus, the Blue Foot is known by several popular names: naked agaric, blavoun, naked tricholome, or naked rhodopaxillus. Historically, it was classified under the names Tricholoma nudum and Rhodopaxillus nudus before being officially recognized under its current name, Lepista nuda.

Hat

Conical in shape when young, the cap of the Pied Bleu measures between 5 and 15 cm in diameter. With age, its margins spread out, and its surface, initially smooth and violet, turns dirty brown as it ages. This cap is slightly hygrophanous, meaning it changes appearance depending on the humidity of the air.

Gills

The gills, thin and close, are an intense violet color when young. They gradually take on brown or ochre hues as they age, and detach easily from each other.

Foot

The stem is cylindrical, relatively bulbous at the base, fleshy and fibrous. Of a marked violet color, it is streaked with whitish fibrils that give it a distinctive striped appearance.

Flesh

The flesh of the Pied Bleu is tender, thick in the cap and more fibrous in the stem. Initially violet, it turns lilac over time. It emits a pleasant fruity smell, and its flavor is mild, sometimes slightly tangy.

2) Ecology of the Pied Bleu: A Child of the Forests

The Pied Bleu mainly develops in deciduous and coniferous forests, preferring soils rich in organic debris like dead leaves and pine needles. This mushroom has the peculiarity of growing in a "fairy ring", a natural formation where mushrooms grow in a circle. It appears at the beginning of winter, usually after the first cold snap or frost.

3) Nutritional Values and Medicinal Properties

The Pied Bleu, besides being tasty, has interesting nutritional and medicinal properties. Rich in vitamin B, it also has antibacterial and antifungal properties. However, it is crucial to consume it well cooked, as raw it contains hemolysins, molecules that can attack red blood cells. Once properly prepared, the Pied Bleu retains a crunchy texture and exquisite flavor.

Source: wikipedia

4) Cultivating Blue Foot: A Process to Master

Commercial cultivation of Blue Foot follows methods similar to those used for the button mushroom. Its production generally focuses between August and November, after a period of frost and cold. To ensure fruiting in autumn, it is essential to plant the mycelium early in spring. If this is not done, the mushroom will only fruit the following summer.

What You Will Need

• Mycelium: A 3-kilogram bag of mycelium can cover a plot of 1.5 meters by 1.5 meters.
• Substrate: +-1/4 to 1/2 cubic meter, equivalent to an area of 9 square meters with a depth of 10 centimeters. Use composted hardwood leaves and composted manure/straw.
• Cardboard without dyes containing heavy metals.

Cultivation Methods

Method 1: Outdoor Cultivation

• Preparation of the growing bed: Dig a soil bed 20 to 25 cm deep. Fill it with compost from various organic materials, then add the mycelium in the top 10 centimeters. Finally, also add the gobetage soil as described previously.
• Planting and watering: Add 7-8 centimeters of substrate, mixing in a generous amount of mycelium. Compact the surface to eliminate air pockets and water lightly.
• Growth monitoring: Mycelium colonization should take between 6 to 12 months, depending on the weather and the time of inoculation. It is recommended to create your cultivation trays in spring for fruiting in autumn.

Method 2: Cultivation in trays (Indoor)

Although Lepista nuda is usually cultivated outdoors, indoor cultivation is also possible thanks to research conducted by INRA, which has developed more commercial techniques since the 2000s.

• Substrate preparation: Soak the substrate for 2 days to ensure it is well hydrated, then drain.
• Container filling: Fill the pots with the substrate leaving 5 centimeters below the edge for the gobetage layer. Keep out of direct sunlight.
• Fruiting: Once the substrate is colonized, cover it with the gobetage soil. A cold shock is necessary to initiate fruiting. Adding certain nematodes can also stimulate fruiting by mimicking natural conditions.

Gobetage Soil Recipes

To promote the fruiting of Pieds Bleus, it is recommended to use gobetage soil, which can be prepared in several ways:

• Sphagnum gobetage soil: Mix 1.3 kg of dry sphagnum with 3 liters of water and add 2 tablespoons of hydrated lime.
• Balanced potting soil: Use a potting soil with balanced pH, mixed with mature compost rich in microorganisms.
• Garden soil: As a last resort, your garden soil can also be used for gobetage.

5) Recipe: Pieds Bleus Gratin

Here is a delicious way to cook Pieds Bleus:

• Ingredients:
• 500 g of Pieds Bleus, cleaned and sliced
• 3 medium potatoes, peeled and thinly sliced
• 1 onion, finely sliced
• 2 cloves of garlic, chopped
• 200 ml of crème fraîche
• 100 g of grated cheese (parmesan or gruyère)
• 50 g of butter
• Salt, pepper, and nutmeg to taste
• Fresh parsley for garnish
• Method:
• Preheat the oven to 180°C.
• Sauté the onions and garlic in butter until golden. Add the Pieds Bleus and sauté until tender.
• In a gratin dish, arrange a layer of potatoes, add some of the sautéed mushrooms, then repeat until all ingredients are used.
• Pour the crème fraîche over everything, then season with salt, pepper, and a pinch of nutmeg.
• Sprinkle with grated cheese and bake for about 45 minutes, or until the gratin is golden and the potatoes are fully cooked.
• Garnish with fresh parsley and serve hot.