Where garden water goes
Plant use
Roots take water for metabolism, photosynthesis, and cooling through the leaves
Evaporation
Heat and sun pull moisture off the bare surface
Deep drain
Water that sinks below the root zone is lost
Misses
Water landing where there are no roots evaporates or sinks unused
Root room
Yield tracks root spread. Canopy width is often about the same as the root ball, sometimes a third wider
Hold more in the soil
Organics
Compost, peat, coir, or charcoal hold more water than mineral soil, especially in sand
Crystals
Water-holding polymers swell when you irrigate and release moisture as the mix dries
Mulch
A surface organic layer cuts evaporation and keeps the top inches wet longer
Cover
A heavy opaque ground cover cools soil, slows weeds, and keeps moisture in
Fertility bonus
Water that stays in the root zone also keeps dissolved nutrients there
Underground reservoirs
Liner
An impermeable sheet or tray at the bottom of a hole or bed stops vertical loss
Sides
Bring plastic 6 to 8 inches up the walls so it acts like a tray, not a flat sheet
Fill
Gravel or a similar open layer keeps soil from packing the reservoir
Wicks
Braided nylon rope from the pool to the surface guides roots and lifts water by capillary action
Gauge
A simple float tube shows when the hidden pool is high or low
Holes
Dig 1 to 10 feet wide and 1 to 4 feet deep, then amend native soil or replace it with mix