Kathryn Heilman age 10, of Allentown Penn.,

What is humus?

Humus is one of our words for soil. We can say that plants grow in the earth, the dirt or the soil. Sometimes we need to describe a special rich soil in which plants thrive better than usual. The word for this kind of soil is humus.

It seems strange, but plants love best the dirtiest soil. That is the soil teeming with decaying plants, animals and waste materials from their bodies. This rotting material is full of plant food. Nature uses these valuable chemicals over and over again. Fallen leaves and the dead bodies of animals are broken up into simple chemicals by decay bacteria. That way, nothing is wasted, for new plants can use these chemical foods to grow.

You can make a supply of humus by burying a pile of last years leaves. Add some dead grasshoppers and manure from the farm yard. Billions of busy little bacteria will break up this waste material with the soil. The final mixture is fine for growing your favorite plants.