土壌の準備

Assess soil condition and build healthy, living soil through amendment, composting, and biological activation.

使用タイミング

• You are starting a new garden bed and need to assess the existing soil
• Your plants are underperforming despite adequate water and light (soil is the likely cause)
• You want to transition from conventional to organic or biodynamic practice
• Soil has become compacted, depleted, or hydrophobic
• You need to build a composting system
• You want to apply biodynamic preparations (500-508)

入力

• 必須: Access to the soil to be assessed (garden bed, field, or container)
• 任意: Current soil test results (pH, N-P-K, organic matter %)
• 任意: Garden history (previous crops, amendments applied, years cultivated)
• 任意: Target crops or plants to be grown
• 任意: Approach preference (organic, biodynamic, permaculture)

手順

ステップ1: Assess the Soil

Three field tests that require no laboratory — do all three.

Test 1: Jar Test (Texture — Sand/Silt/Clay Ratio)
1. Fill a quart jar 1/3 full with soil from 15cm depth
2. Fill to top with water, add 1 tablespoon dish soap
3. Shake vigorously for 3 minutes, then set on level surface
4. Read layers after settling:
   - Sand settles in 1 minute (bottom layer)
   - Silt settles in 4-6 hours (middle layer)
   - Clay settles in 24-48 hours (top layer)
5. Measure each layer as % of total soil depth
   - Ideal garden soil: ~40% sand, ~40% silt, ~20% clay (loam)

Test 2: Spade Test (Structure and Compaction)
1. Push a spade into moist soil to full depth (25cm)
2. Lever up a block of soil and place on a board
3. Observe:
   - Crumbles easily → good structure
   - Breaks into angular blocks → compacted
   - Smears or is sticky → too much clay or waterlogged
   - Layers visible → hardpan or plough pan present
4. Smell the soil:
   - Sweet, earthy → healthy aerobic biology
   - Sour, sulphurous → anaerobic conditions (drainage problem)

Test 3: Earthworm Count (Biological Activity)
1. Dig a 30cm × 30cm × 30cm cube of soil
2. Place on a tarp or board
3. Gently break apart and count earthworms
   - 0-5: Poor biology — needs organic matter
   - 5-10: Fair — improving but not yet thriving
   - 10-20: Good — healthy biological activity
   - 20+: Excellent — this soil is alive

期待結果: Clear picture of soil texture, structure, and biology. A jar test result, a structure rating, and a worm count.

失敗時: If jar test layers are hard to distinguish, repeat with cleaner water and more vigorous shaking. If worm count is zero and soil smells sour, the soil may be anaerobic — drainage must be addressed before amendment.

ステップ2: Diagnose and Plan Amendment

Match your assessment to an amendment plan.

Amendment by Soil Type:
┌────────────────┬─────────────────────────┬──────────────────────────────┐
│ Diagnosis      │ Symptoms                │ Amendment                    │
├────────────────┼─────────────────────────┼──────────────────────────────┤
│ Heavy clay     │ Sticky, slow drainage,  │ Gypsum (calcium sulfate)     │
│                │ >40% clay in jar test   │ 1 kg/m², worked into top     │
│                │                         │ 15cm. Add coarse compost.    │
│                │                         │ Plant daikon radish to break │
│                │                         │ hardpan biologically.        │
├────────────────┼─────────────────────────┼──────────────────────────────┤
│ Sandy          │ Drains instantly, won't │ Compost 5-10cm thick, worked │
│                │ hold moisture, <20%     │ into top 20cm. Add biochar   │
│                │ silt+clay in jar test   │ (pre-charged with compost    │
│                │                         │ tea) for moisture retention.  │
├────────────────┼─────────────────────────┼──────────────────────────────┤
│ Depleted       │ Pale colour, low worm   │ 10cm compost top-dress.      │
│                │ count, poor growth      │ Cover crop (legume mix) for  │
│                │ despite watering        │ nitrogen fixation. Foliar    │
│                │                         │ seaweed spray monthly.       │
├────────────────┼─────────────────────────┼──────────────────────────────┤
│ Compacted      │ Angular blocks in spade │ Broadfork (not rototiller)   │
│                │ test, surface pooling,  │ to fracture without          │
│                │ hard when dry           │ inverting. Deep mulch (15cm  │
│                │                         │ wood chips on paths). Plant  │
│                │                         │ deep-rooted comfrey.         │
├────────────────┼─────────────────────────┼──────────────────────────────┤
│ Acidic (pH<6)  │ Blueberries thrive but  │ Wood ash (light application) │
│                │ brassicas struggle      │ or dolomite lime. Test pH    │
│                │                         │ before and after — adjust    │
│                │                         │ slowly over 2 seasons.       │
├────────────────┼─────────────────────────┼──────────────────────────────┤
│ Alkaline (pH>7)│ Iron chlorosis (yellow  │ Elemental sulphur or acidic  │
│                │ leaves, green veins)    │ compost (pine needles, oak   │
│                │                         │ leaves). Very slow to shift. │
└────────────────┴─────────────────────────┴──────────────────────────────┘

期待結果: A specific amendment plan matched to the diagnosed soil condition.

失敗時: If multiple conditions overlap (e.g., heavy clay AND depleted), address structure first (gypsum + broadfork), then biology (compost + cover crop). Trying to fix everything at once overwhelms the soil.

ステップ3: Build Compost

Choose a method based on available space, materials, and timeline.

Composting Methods:
┌────────────────┬──────────────┬──────────────┬─────────────────────────┐
│ Method         │ Time to      │ Space Needed │ Best For                │
│                │ Finished     │              │                         │
├────────────────┼──────────────┼──────────────┼─────────────────────────┤
│ Hot compost    │ 4-8 weeks    │ 1m³ minimum  │ Large gardens, weed     │
│                │              │              │ seed / disease kill      │
├────────────────┼──────────────┼──────────────┼─────────────────────────┤
│ Cold compost   │ 6-12 months  │ Any size     │ Low effort, small       │
│                │              │              │ quantities              │
├────────────────┼──────────────┼──────────────┼─────────────────────────┤
│ Vermicompost   │ 3-6 months   │ 0.5m² indoor │ Kitchen scraps, indoor  │
│                │              │              │ / apartment gardens     │
└────────────────┴──────────────┴──────────────┴─────────────────────────┘

Hot Compost Protocol:
1. Build pile in layers — 2 parts brown (carbon) to 1 part green (nitrogen)
   - Brown: dried leaves, straw, cardboard, wood chips
   - Green: kitchen scraps, fresh grass, manure, coffee grounds
2. Moisten each layer (damp sponge consistency)
3. Pile must be at least 1m × 1m × 1m to reach temperature
4. Internal temperature should reach 55-65°C (130-150°F) within 3-5 days
5. Turn pile when temperature drops below 45°C (every 5-7 days)
6. After 3-4 turns, cure for 2-4 weeks without turning
7. Finished compost: dark, crumbly, smells like forest floor, no recognizable inputs

Never Compost:
- Meat, dairy, oils (attract pests)
- Diseased plant material (unless hot compost reaches 60°C+ for 3 days)
- Treated wood, glossy paper
- Pet waste (pathogen risk)

期待結果: Composting system established and first batch in progress.

失敗時: If hot compost won't heat up: check moisture (too dry or too wet), check C:N ratio (add more green for nitrogen), check pile size (below 1m³ won't heat reliably).

ステップ4: Apply No-Till and Cover Cropping

Protect and build soil structure without inversion.

No-Till Sheet Mulching (New Bed from Lawn or Weeds):
1. Mow or scythe existing vegetation as low as possible
2. Layer cardboard (overlapping edges) directly on ground — no gaps
3. Wet cardboard thoroughly
4. Add 5cm compost on top of cardboard
5. Add 10-15cm organic mulch (straw, wood chips, leaves)
6. Wait 3-6 months (autumn application → spring planting)
7. Plant through mulch by pulling it aside — do not till

Cover Crop Quick Reference:
┌─────────────────┬────────────────┬───────────────────────────────┐
│ Crop            │ Season         │ Benefit                       │
├─────────────────┼────────────────┼───────────────────────────────┤
│ Crimson clover  │ Autumn sow     │ Nitrogen fixation, bee forage │
│ Winter rye      │ Autumn sow     │ Biomass, weed suppression     │
│ Buckwheat       │ Summer sow     │ Fast cover, phosphorus mining │
│ Phacelia        │ Spring/autumn  │ Pollinator magnet, breaks up  │
│                 │                │ compaction                    │
│ Daikon radish   │ Autumn sow     │ Deep root breaks hardpan,     │
│                 │                │ decomposes in place over      │
│                 │                │ winter (bio-drill)            │
└─────────────────┴────────────────┴───────────────────────────────┘

Terminate cover crops by:
- Crimp and roll (best — leaves roots in place)
- Scythe and lay as mulch
- Never rototill — this destroys the soil structure you're building

期待結果: Soil protected year-round, biology undisturbed, organic matter increasing.

失敗時: If cover crop fails to establish, check sowing depth (most need surface or shallow sowing) and moisture. Resow or apply thick mulch as substitute ground cover.

ステップ5: Biodynamic Preparations (Optional — Advanced)

For practitioners following Demeter or biodynamic principles.

Biodynamic Preparations Overview:
┌──────┬───────────────┬──────────────────────┬─────────────────────────┐
│ Prep │ Material      │ Application          │ Purpose                 │
├──────┼───────────────┼──────────────────────┼─────────────────────────┤
│ 500  │ Horn manure   │ Spray on soil,       │ Stimulate soil biology,  │
│      │               │ autumn & spring      │ root growth, humus      │
├──────┼───────────────┼──────────────────────┼─────────────────────────┤
│ 501  │ Horn silica   │ Spray on foliage,    │ Light metabolism, fruit  │
│      │               │ morning, summer      │ quality, ripening       │
├──────┼───────────────┼──────────────────────┼─────────────────────────┤
│ 502  │ Yarrow        │ Added to compost     │ Sulphur and potassium   │
│ 503  │ Chamomile     │ Added to compost     │ Calcium, stabilizes N   │
│ 504  │ Stinging nettle│ Added to compost    │ Iron, stimulates soil   │
│ 505  │ Oak bark      │ Added to compost     │ Calcium, disease resist │
│ 506  │ Dandelion     │ Added to compost     │ Silica, light forces    │
│ 507  │ Valerian      │ Sprayed on compost   │ Warmth, phosphorus      │
├──────┼───────────────┼──────────────────────┼─────────────────────────┤
│ 508  │ Horsetail tea │ Spray on foliage     │ Fungal disease prevent  │
└──────┴───────────────┴──────────────────────┴─────────────────────────┘

Preparation 500 Application:
1. Stir 100g horn manure in 35 litres warm water
2. Stir dynamically for 1 hour — create vortex, reverse, create vortex
   (alternating direction every minute)
3. Apply within 1 hour of stirring
4. Spray in large droplets on soil surface — late afternoon, descending moon
5. Apply autumn (before winter) and early spring (before sowing)

Note: Biodynamic preparations are available from certified suppliers
or local biodynamic farming groups. Making your own requires the
previous season's preparations and specific animal horn sheaths.

期待結果: Preparations applied at correct time and moon phase. Soil biology activation visible over 1-2 seasons.

失敗時: If preparations are unavailable, good compost and cover cropping achieve 80% of the biological benefit. Preparations enhance but are not a substitute for sound soil management.

ステップ6: Heal Checkpoint — Post-Amendment Assessment

Six weeks after amendment, reassess the soil.

Post-Amendment Soil Health Check:
1. Repeat the spade test:
   - Has structure improved? (Crumbles more easily)
   - Are roots penetrating deeper?
   - Any remaining hardpan layers?

2. Repeat the earthworm count:
   - Has the count increased? (Even 2-3 more is progress)
   - Are worms distributed through the depth or just at surface?

3. Drainage test:
   - Dig a 30cm hole, fill with water, let drain, refill
   - Second fill should drain within 1-4 hours
   - <1 hour: very free draining (may need more organic matter)
   - >4 hours: still compacted or clay-heavy (continue treatment)

4. Surface observation:
   - Fungal threads visible in mulch layer? (Good — decomposition active)
   - Green algae on surface? (Too wet or too compacted)
   - Mulch layer breaking down? (Biology is working)

Triage:
- All improving → Continue current approach, reassess next season
- Structure improved but worms low → Add more diverse organic matter
- Worms present but drainage poor → Broadfork again, add coarse material
- No improvement → Soil may have contamination — consider lab test for heavy metals

期待結果: Measurable improvement in at least 2 of 3 indicators (structure, biology, drainage).

失敗時: If no improvement after 6 weeks, the issue may be deeper than topsoil amendment can address. Consider raised beds with imported soil mix as a parallel strategy while continuing to improve the in-ground soil over multiple seasons.

バリデーション Checklist

• All three field tests completed (jar, spade, earthworm)
• Soil type correctly diagnosed from test results
• Amendment plan matches diagnosed condition
• Compost system established (hot, cold, or vermi)
• Soil covered year-round (mulch, cover crop, or living plants)
• No rototilling or soil inversion
• Heal checkpoint performed 6 weeks post-amendment
• Garden journal updated with test results and amendment applied

よくある落とし穴

1. Adding without testing: Random amendments waste money and can worsen imbalances. Always test first
2. Rototilling: Feels productive but destroys soil structure, kills earthworms, and brings weed seeds to surface. Use a broadfork if you must loosen
3. Bare soil: Exposed soil loses moisture, structure, and biology. Always mulch or plant cover crops
4. Fresh manure on beds: Burns roots and introduces pathogens. Compost all manure for at least 6 months before soil contact
5. Lime without testing pH: Overliming makes nutrients unavailable. Only adjust pH based on actual test results
6. Expecting instant results: Soil building is measured in seasons and years, not weeks

関連スキル

• cultivate-bonsai — Bonsai soil mix (akadama/pumice/lava) is a specialized soil preparation
• plan-garden-calendar — Soil amendment timing aligns with seasonal calendar (autumn for lime, spring for compost)
• read-garden — Soil observation is part of the garden reading protocol
• heal — Post-amendment assessment follows the heal triage pattern
• forage-plants — Understanding soil-plant relationships aids wild plant habitat reading
• make-fire — Wood ash from fire is a traditional soil amendment (potassium + lime)