How long does it take for plants to return to land covered by molten lava?

     The ash and cinders that were blown out of the volcano contain minerals that plants can use. Cinders and ash are small bits of stone, and rain water pours down through them until it hits a rock layer in the ground below. Although this jumble of small rock particles can make water available for roots, it also allows the water to keep on draining down, leaving the roots in dry stones again after only a few minutes. It may have excellent drainage, but poor water-holding capacity.

     Soil is not made of minerals alone. It contains little bits of organic material that are being broken down by decomposers. Decomposers are living organisms such as bacteria, fungi, tiny nematode worms, and other organisms that may be too small for us to even see. They digest dead stems and leaves, and the bones, feathers and flesh of dead animals. They recycle the nutrients so that they may be used again.  Soils are living communities of organisms, and they take time to develop after volcanic eruptions.