Soil & potting mix
Best soil for Curly Kale (Brassica oleracea var. sabellica 'Curly Kale')
Also called curly kale, Scots kale, common kale.
More about curly kale
About Curly Kale
Brassica oleracea var. sabellica 'Curly Kale' · also called curly kale, Scots kale · edible
Curly kale is a hardy leafy brassica with tightly ruffled, frilly leaves on an upright stem. Exceptionally cold-tolerant, it crops through autumn and winter and actually sweetens after frost. Grow in full sun in firm, fertile, alkaline-leaning soil, keep it well watered and netted against cabbage pests, and pick young leaves over a long season.
Preferred mix: Firm, fertile, well-drained soil, pH 6.5-7.5
Watch for — Clubroot: Soil-borne disease swelling and distorting roots, stunting plants in acidic, wet ground. Lime the soil, improve drainage, rotate brassicas, and never compost infected roots.
Why curly kale needs this mix
Curly Kale is a hungry, thirsty crop — it wants a rich, moisture-retentive but free-draining loam, well fed and never baked dry.
- Curly Kale grows fast and has a big crop to fill, so it draws heavily on both nutrients and water — a lean mix simply cannot keep up.
- Plenty of organic matter holds moisture evenly, which prevents the stress problems (bolting, bitterness, blossom-end rot) that come from a drying-then-flooding cycle.
- It still needs structure: rich does not mean airless, so grit, perlite or leaf mould keeps roots oxygenated.
For the full picture on what makes up a good mix, see our guide to the main types of soil and potting media — it explains why each ingredient above behaves the way it does.
What goes wrong with the wrong mix
The wrong soil is one of the most common reasons curly kale struggles, and the damage often shows up weeks later as a watering problem. For this species specifically:
- A poor, thin or sandy mix starves curly kale — growth stalls, leaves pale, and yields collapse.
- A heavy, compacted, badly drained soil rots the roots and brings fungal problems despite all the feeding.
- Letting a rich mix dry to dust then drowning it causes the classic moisture-stress disorders this crop is prone to.
Under-feeding and inconsistent moisture. Curly Kale needs genuinely rich soil plus steady watering — most disappointing crops come down to one or both being short.
pH — does it matter for curly kale?
Curly Kale does best around pH 6.0-7.0 (slightly acidic to neutral). It is worth a cheap soil test for an outdoor bed; very acidic soil benefits from a little lime well before planting.
If you want to check or adjust it, the soil pH guide walks through testing and the safe ways to nudge a mix more acidic or more alkaline.
DIY mix vs a bagged one
For containers a good multipurpose or vegetable compost works for curly kale with extra feed through the season. For beds, the real win is digging in plenty of well-rotted compost or manure — that beats any bag.
Drainage and the pot
Rich but free-draining is the target: raised beds and large containers both deliver it. Mulch heavily to even out moisture and roughly halve how often you water.
Curly Kale is usually grown for a single season, so "repotting" means starting fresh each year — never reuse exhausted, disease-prone compost for the same crop family. When the time comes, our repotting guide for curly kale covers the timing and technique step by step.
Curly Kale soil — frequently asked questions
What is the best soil mix for curly kale?
3 parts compost-amended loam or quality multipurpose compost : 1 part well-rotted garden compost or manure : 1 part perlite or grit (containers) / leaf mould (beds). Curly Kale grows fast and has a big crop to fill, so it draws heavily on both nutrients and water — a lean mix simply cannot keep up.
Can I use normal potting soil for curly kale?
A poor, thin or sandy mix starves curly kale — growth stalls, leaves pale, and yields collapse. For containers a good multipurpose or vegetable compost works for curly kale with extra feed through the season. For beds, the real win is digging in plenty of well-rotted compost or manure — that beats any bag.
Does curly kale need a special pH?
Curly Kale does best around pH 6.0-7.0 (slightly acidic to neutral). It is worth a cheap soil test for an outdoor bed; very acidic soil benefits from a little lime well before planting.
Should I buy a bagged mix or make my own for curly kale?
For containers a good multipurpose or vegetable compost works for curly kale with extra feed through the season. For beds, the real win is digging in plenty of well-rotted compost or manure — that beats any bag.
How often should I refresh the soil for curly kale?
Curly Kale is usually grown for a single season, so "repotting" means starting fresh each year — never reuse exhausted, disease-prone compost for the same crop family. Rich but free-draining is the target: raised beds and large containers both deliver it. Mulch heavily to even out moisture and roughly halve how often you water.
Keep reading
- Curly Kale care — the full brief (light, water, humidity, problems, pet safety)
- How often to water curly kale — the schedule the mix feeds into
- Repotting curly kale — when and how to refresh the mix
- Soil pH guide — test it and adjust it safely
- Should I water my plant? The simple check first
- Why is my plant wilting? Wet vs dry diagnosis
- Underwatered plant — signs and how to rehydrate it
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- All 2464 soil and potting-mix guides in the Growli library