Target soil pH by crop
Most vegetables want 6.0–6.8, but potatoes are held acid on purpose and brassicas alkaline on purpose — the exceptions are the whole point of this table.
Target soil pH by crop
Most of gardening treats "6.5" as the answer for everything. It mostly is — but four of the groups below are deliberate exceptions, and getting those wrong causes the specific diseases gardeners then try to spray away.
| Crop group | Target pH | Why this band |
|---|---|---|
| Most vegetables | 6–6.8 | The default band for a mixed vegetable bed. |
| Brassicas | 6.5–7.5 | Held deliberately high — clubroot is suppressed above about 7.0. |
| Potatoes | 5–5.5 | Held deliberately low. Liming potato ground invites scab. |
| Blueberries | 4.5–5.5 | Needs acid soil. This bed usually wants sulfur, not lime. |
| Asparagus | 6.5–7.5 | Tolerates and prefers the alkaline end. |
| Tomatoes and peppers | 6.2–6.8 | Calcium availability matters here — blossom-end rot tracks it. |
| Berries (cane and bush) | 5.5–6.5 | Slightly acid. Raspberries and blackberries sit at the top of this band. |
| Lawn and grass | 6–7 | Wide tolerance; most turf problems are nitrogen, not pH. |
The exceptions that matter
Potatoes are held low on purpose. Common scab is suppressed in acid soil, so liming potato ground to the usual 6.5 invites the scabby skin people blame on the seed. If potatoes and brassicas share a rotation, they cannot share a pH — that is what the rotation is for.
Brassicas are held high on purpose. Clubroot is suppressed above about pH 7.0, which is why cabbage ground gets limed harder than the rest of the plot.
Blueberries are not a pH problem, they are a different soil. At 4.5–5.5 they need acidifying, not liming, and elemental sulfur is the tool. A blueberry planted into a limed vegetable bed yellows from iron chlorosis within a season.
Tomatoes and peppers care about calcium availability more than about the pH digit — blossom-end rot tracks calcium uptake, and uptake falls off outside the band.
Getting there
Moving pH up is liming; moving it down is elemental sulfur. Both are slow — months, not weeks — and both are dosed by soil texture, not by how far off the number looks. Work the amendment into the root zone rather than leaving it on the surface, and re-test before repeating.
FAQ
What is the ideal soil pH for a vegetable garden?
6.0–6.8 for a mixed vegetable bed. That band keeps nitrogen, phosphorus and potassium available at the same time; outside it, phosphorus in particular locks up even when the soil contains plenty.
Why do potatoes want acid soil?
Common scab is suppressed below about pH 5.5, so potato ground is deliberately held at 5.0–5.5 and not limed. Liming a potato bed to the usual 6.5 is a common cause of scabby tubers.
What pH do blueberries need?
4.5–5.5 — genuinely acid, and well below anything else in a normal garden. Blueberry beds usually need elemental sulfur rather than lime, and they do poorly planted into ground that was limed for vegetables.
Can I grow everything at one pH?
Most of a vegetable plot, yes, at 6.0–6.8. Potatoes, brassicas and blueberries are the three that genuinely want their own band, so they are worth siting deliberately rather than mixing through the plot.
Sources
Bands are typical published extension ranges for home gardens; regional lab recommendations vary and your own lab's guidance wins.