How should I water living soil, and is my tap water OK?Updated 2 hours ago

Water no more than 5 to 10% of your soil volume at one time, and keep the soil evenly moist, never soaked and never bone dry. Filtered tap water is usually fine, and you do not need to pH adjust it for living soil.

How much and how often

• Multiply your soil volume by 5 to 10%. For example, 30 gallons of soil x 5% = 1.5 gallons of water. A 15 gallon pot takes roughly 0.75 to 1.5 gallons.
• Small containers with big plants need water more often, sometimes daily.
• Large containers with small plants need water less often. Err on the side of less.
• Warm, dry, and growing fast means more water. Cool and humid means less.
• Water at a consistent time, ideally when the lights come on or in the morning.
• Water slowly and evenly, like rain. A pump sprayer works well for small gardens.

How to check

• Lift or tilt the container before and after watering to learn the weight.
• Thump the side. Light and hollow means dry. Dense means wet.
• Keep it mulched so the surface stays moist.

Water source

• Tap water: filtered tap water is our usual recommendation. If your city uses chloramine, make sure your filter is rated for it.
• Softened water: avoid it. Salt-based softeners add sodium that builds up in the soil. Get water from before the softener if you can.
• RO and dehumidifier water: not recommended. They have very little mineral content.
• pH: we do not recommend pH adjusting water for living soil. If your water reads very high, a water test for alkalinity, bicarbonate and sodium tells you more than pH alone.

Full guide: Watering Protocol for the BuildASoil Way.