Why does soil need tiny air holes?

Think of a time you pushed your fingers into soft garden soil. It feels cool and crumbly, and it smells fresh and earthy. If you looked very closely, you would see that it is full of tiny holes.

Many of those holes are even tinier than a grain of sugar, and soil is packed with them. So why does soil need tiny air holes? Let's dig down and find out together.

Soil is made of little crumbs, and between the crumbs sit tiny gaps. Air from above slips down into those gaps and fills them up.

Down among those crumbs, a plant's roots are growing, and roots are alive. Every living part of a plant needs oxygen, which is the part of the air that living things breathe in. Leaves find oxygen all around them, but roots underground can only find it in those air holes.

Near the tip of each root grow root hairs, which are fuzzy threads even thinner than the hair on your head. The root hairs poke into the air holes and soak in the oxygen waiting there. What do you think the root does with all that oxygen?

A root needs energy to grow, just as you need energy to run and play. With oxygen, the root turns the food inside it into that energy. You do the same thing each time you breathe in.

With that energy, the root pushes deeper and spreads wider through the soil. Its root hairs keep drinking water for the plant. Without air in the holes, the roots would run out of energy, and the whole plant would droop.

The same tiny holes help in one more way. When rain falls, water trickles down through them and reaches the thirsty root hairs. Then the extra water drains away deeper, and fresh air slides back into the holes.

Soil needs tiny air holes because living roots need oxygen to make the energy they grow with, and their root hairs soak that oxygen in from the air in the holes. Those same holes let rain trickle down to the root hairs and then fill with fresh air again.

Down in the cool, dark soil, the roots keep reaching between the crumbs. Their root hairs sip water and soak in oxygen from the air holes, while up above, the plant stands tall and green.