Truffles are a delicacy, and are the fruiting body of a fungus that lives symbiotically with the roots of an inoculated tree such as an oak or hazelnut tree.
The fungus (known as a mycorrhiza) is colonised onto the roots of the host tree. Truffles prefer a well-drained soil enriched with compost and decomposed manure.
They require all the usual plant nutrients, but in relatively low amounts (especially phosphate). Soils must have a pH around 8 for truffles to grow. In most gardens, you will need to increase pH by adding lime (see ‘Soil Preparation’ below).
Climatically, truffles need warm to hot summers and cold winters. Choose a site with an open, sunny aspect (north or west facing is best).
Soil preparation
The soil must have an open structure and be well drained. An elevated or sloping site is ideal, or a raised garden bed.
Use a garden fork to loosen and aerate the soil down to about 20cm in a circular diameter of about 2m. Spread about 20 kilograms of Agriculture Lime over the area and incorporate using the garden fork.
This will help to increase soil pH over the next 6 months. Check the pH annually and keep applying lime to increase the pH in the active root zone as the tree grows.
Planting
Dig a hole twice the size of the pot and twice as deep. Backfill with soil enriched with lime. Remove the tree from the pot and plant into the hole, without disturbing the roots. The finished soil level should be the same as the media level in the pot.
Continue to backfill, pressing down firmly to secure your tree. Water thoroughly to remove air pockets in the soil. Stake if necessary.
Maintenance
Water regularly during the first year to help establishment. Do not apply any additional fertilisers, however a weak solution of seaweed extract is beneficial.
Weed regularly, but do not apply an organic mulch as this will decompose and create acidity. Prune any lower branches up to 1.2m and train the tree into a “V” shape. This will allow light to penetrate under the tree.
Harvest
Usually it will take 4 or 5 years for truffles to be produced after planting.
Truffles ripen from late June through to August and are formed under the soil. They need to be carefully unearthed, using all your powers of smell to detect their sweet, earthy fragrance before disturbing the soil.
