Soil science for gardens in Rajasthan

Why we read the ground two metres down before a single plant is chosen.

The soil

What is going on under the lawn.

A garden is only as good as its ground. This is a cut through a planted lawn, two metres deep. We read every site this way before planting — most failures start below the surface, not above it.

Fig. S-01 Section through a planted lawn · scale 1:20

1 Tree canopy: shade, and leaves giving off water
2 Drip pipe, 15 cm below the surface
3 Earthworm
4 Fungal threads
5 Helper fungi on the roots
6 Tiny soil worms
7 Crumbly soil: air and water move freely
8 Water table, rises in the monsoon

The drawing, layer by layer

Leaf litterLeaves and mulch. Keeps the soil cool and damp through a Rajasthan summer. Put there on purpose.

TopsoilThe living layer — most of the roots, worms and fungi. Good topsoil is the difference between a garden that thrives and one that struggles.

Pale layerWashed thin by years of water. Poor on its own; deep roots pass straight through.

SubsoilWhere a tree anchors and finds water in the dry months. Compacted subsoil keeps trees small, so we loosen it before planting.

Broken rockRock breaking down into soil. Drains freely; roots rarely go past it.

BedrockSolid rock. The water table rises above it in the monsoon, which is why some sites need drainage.

What lives there, and why it matters

Earthworms tunnel through the topsoil and let air and water in. Fungal threads (the fine lines in the drawing) link up with tree roots and fetch water and minerals the roots cannot reach on their own; we call these helper fungi. Soil bacteria break down the leaf litter into food for plants. None of this survives chemical fertiliser used carelessly, which is why we feed the soil with compost and mulch instead.

What we do with this

We dig a pit on site and read these layers before any planting plan: how deep the topsoil runs, whether the subsoil is compacted, where the water sits, which trees will be happy there. The drip line sits fifteen centimetres down; the canopy shades the ground so less water evaporates.

In practice

It is why our gardens are still healthy in their tenth summer: the soil was understood before the first plant went in.