Simple pH Testing Without Overthinking It
Okay. After the white crust lesson I got a bunch of questions that all boiled down to the same thing: fine, Debbie, but how do I actually know what my pH is. Am I supposed to just guess?
No. But you also don't need to turn this into a chemistry degree.
Buy the cheap kit, not the fancy one
Go to the garden center and get a basic soil pH test kit. There's usually a cheap one with little vials and colored liquid, and there's a fancier probe-meter thing that costs more and, in my experience, is fussier and less reliable than the vials. I use the cheap one. It works fine.
You don't need a lab. You need a number that's close enough to tell you which direction to move.
How to actually take the sample
Here's where people mess it up, and it's an easy fix.
- Dig down 4 to 6 inches. Not just the surface. That white crust we talked about last time sits right on top and it'll skew your reading if you scoop from there.
- Pull soil from three or four spots in the bed, not just one corner. Mix it together in a little bowl or a cup.
- Let it dry out a bit if it's soaking wet. Wet soil can throw the color reading off.
- Follow the kit instructions for how much soil and how much water or solution to use. They're all a little different.
- Wait the full time the instructions say before you read the color. I know it's tempting to peek early. Don't. Give it the minutes it asks for.
That's it. Compare your color to the chart, write the number in your garden journal, and you're done.
What the number actually means
Most vegetables want something in the 6.0 to 7.0 range, slightly acidic to neutral. Our native soil here runs alkaline, often up in the 7.5 to 8.0 range or higher, especially if you're on well water like I am. That's not a surprise if you've been in the last couple lessons. It's just confirming what the crust already told you.
If you're gardening in a raised bed with a mix you built yourself, you're usually closer to that 6.5 to 7.0 sweet spot already, because you controlled what went in. If you're testing native ground, expect it to run high, and don't panic about it. High alkaline soil isn't a death sentence, it's a thing you manage. Add organic matter, watch your water, don't be shocked when the number doesn't move fast.
Don't test every week
Here's my actual opinion on this, since people ask: test once at the start of the season, maybe again mid-summer if something looks off, and that's plenty. I know some people want to test constantly and chase the number around. Don't. Soil pH moves slowly. Testing every week just gives you more numbers to worry about, not more control.
Why I'm careful about "early" now
I'll tell you why I take timing seriously with soil stuff in general, testing included.
A few years back I direct-sowed a row of carrots too early in spring. Ground was still cold, I was impatient, and I just went for it. Half those seeds sat in cold, wet dirt and rotted before they ever did anything. The other half came up fine, eventually, once it warmed up.
Same idea applies here. If you test pH when the soil's freezing cold or waterlogged from snowmelt, you're going to get a squirrelly reading that doesn't reflect what your bed is actually going to do once the season's underway. Wait until the ground's workable, not frozen, not soup. Same rule I should've followed with those carrots. I write my sow dates on a popsicle stick in the bed now so I stop guessing at timing on anything, testing included.
A plain caution
The little vials in most kits have a mild reagent liquid in them. It's not dangerous stuff, but don't drink it, keep it away from little kids who think vials of colored liquid look like a snack, and wash your hands after. Common sense, not a big deal, just say it out loud once.
Before next time
Grab a cheap pH kit before our next session and test one bed, native ground if you've got it. Bring your number, even if it's ugly. We'll talk about what to do with it.
- D