Peat is an accumulation of organic matter consisting of decomposed leaves, grass, fungi and insects. Peat is the soil used for most potted plants available in supermarkets, because it is very easy to transport, but also nutritious enough for the plant, at least until transplanting. Peat weighs very little and has a very dark, almost black color.
It can be mixed with garden soil or with sandy soil, for better drainage. Peat also acts as a mild natural fall fertilizer, but it is not strong enough to replace fertilization. Plants will take from it only a small part of the minerals they need, resulting from decomposed leaves, fungi, insects and animal residues. However, the advantage of peat is that it absorbs and retains very well the minerals it receives from fertilizers, so the root will have provisions for longer than if it were planted in a simple garden soil.
Peat is very important for farmers and gardeners because it improves the structure of cultivated lands and increases soil acidity. Another reason why peat is appreciated is due to the fact that it provides good drainage, keeping the moisture in the soil, but preventing excess water and its negative consequences (e.g. rotten roots).