How do weeds grow without sunlight?


My high school biology said plants need sun and water to grow. I laid down heavy-duty fabric in my backyard and covered that with mulch. Somehow, weeds still managed to burst through the fabric, flourish and grow.

A secondary question to this would be: Are there any plants I could put in my bathroom, that has zero natural light, that would stay healthy and grow?

In: 0

Seeds contain a reserve of nutrients to allow the plant to grow enough to reach the surface and sprout leaves.

Also, many “weed” plants have large nutrient reserves in their root systems, so if you chop them off but leave the roots, they can grow back without sunlight.

Neither of these strategies works long term, but in the short term, plants can still grow for a while without sunlight.

Weeds like most plants have enormous amounts of energy reserves stored up in the seed which enables them to grow rapidly before needing to recharge with photosynthesis.

The light that plants need doesn’t have to be sunlight, its just that sunlight is much stronger than the lights in your house. So plants that normally grow in direct sunlight won’t get enough light to survive in your bathroom.

There are, however, plants that are adapted to places where hardly any natural light reaches. A forest floor beneath layers of light-absorbing tree leaves is one such place. Others grow inside caves where only the faintest scattering of sunlight reaches. (Recently Chinese botanists found a type of nettle that only needs 0.04% of normal sunlight.) In caves that are lit for tourists you sometimes see clumps of moss and fern clustered around light bulbs far from thesurface.