How to check soil moisture before you water
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How to check soil moisture before you water
Most of the trouble people have with a new garden comes back to water, and it's almost never that they didn't care enough, because the ones losing plants are usually the ones out there with the hose every evening. Soil holds water differently depending on what it's made of, so until you know what's happening a few centimetres down, you're watering on a guess and the plant is the one paying for it.
Your soil decides how often you water
Sand and clay sit at opposite ends of this. Sandy soil drains fast and dries from the top down, so it wants a smaller drink more often, while clay hangs on to water and can stay soggy well below the surface long after the top looks bone dry, which is where root rot comes from. Loam is the middle ground everybody is trying to get to, and the quickest way to work out which one you've got is to grab a handful, squeeze it and open your hand. If it falls apart straight away it's sandy. If it holds a sticky lump it's clay. If it holds together and then crumbles when you poke it, you've got loam and you're doing better than most of us.
The finger test, and the thing that does it properly
Push a finger into the soil to the second knuckle, which is about 5cm, and if it's damp down there you don't need to water at all, however dry the surface looks. A crusty top on a bed that's still wet underneath is completely normal and it fools people constantly, which is why so many plants get drowned by somebody being kind to them. If you'd rather not guess, a soil moisture meter reads the moisture down at root depth and takes the argument out of it, and it's the first thing I'd hand to anyone who keeps losing plants and can't work out why.
Water deeply, and less often
A light sprinkle every day wets the top couple of centimetres and nothing else, so the roots stay up near the surface where they cook on the first proper hot day. A long slow soak that gets water down to 20 or 30cm gives the roots a reason to follow it down, and a plant with deep roots will ride out a dry week without you doing a thing. Early morning is the time for it, because the water gets into the soil before the heat takes it back, and the leaves dry off during the day instead of sitting wet all night, which is how a lot of fungal trouble gets started.
Mulch does more for moisture than the hose does
A decent layer of mulch, somewhere around 50 to 75mm, keeps the sun off the soil and slows evaporation right down, and that's the difference between a bed that's still damp at lunchtime and one that's gone to dust. Pull it back a few centimetres from stems and trunks so you aren't holding wet material against the plant. Sugar cane and pea straw both break down into the soil as they go, so they're feeding the bed the whole time they're protecting it.
Which way the bed faces matters as much as the watering
Worth knowing before you site a new bed or move a pot: here it's the west and the afternoon that bakes, and north is the aspect that gives you good light without cooking anything. A bed taking the full west sun will dry out faster than a north-facing one no matter what you do to the soil, so it's worth getting that right first and then worrying about the watering.
Shop related products
- Easy Wetta Garden Mulch, 50L. Mulch that lets water through instead of shedding it.
- Brunnings Ultimate Dig It In Compost 30L. Works through a bed to help sand hold water and clay let it go.
- Naturally Good Garden Soil, 50L. For filling a new bed or topping up a tired one.
- Go Go Juice 1 Litre. A soil probiotic that feeds the microbes doing the work down there.
Did you know we also stock a soil moisture meter and bagged gypsum in the shop. Neither of them is on the website, so give us a ring on (08) 8536 4333 to check what's on the shelf.
The rest of the range is in our garden centre, and if you're not sure which way your soil leans, bring a handful in and we'll have a look at it with you.
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Still checking with a finger before I turn the tap on, and still getting it wrong often enough to keep me honest.
Cheers,
Candeece
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