pjt222 Prepare Soil
Assess soil condition and build healthy, living soil through amendment, composting, and biological activation.
When to Use
- 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)
Inputs
- Required: Access to the soil to be assessed (garden bed, field, or container)
- Optional: Current soil test results (pH, N-P-K, organic matter %)
- Optional: Garden history (previous crops, amendments applied, years cultivated)
- Optional: Target crops or plants to be grown
- Optional: Approach preference (organic, biodynamic, permaculture)
Procedure
Step 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
Expected: Clear picture of soil texture, structure, and biology. A jar test result, a structure rating, and a worm count.
On failure: 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.
Step 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. │
└────────────────┴─────────────────────────┴──────────────────────────────┘
Expected: A specific amendment plan matched to the diagnosed soil condition.
On failure: 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.
Step 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)
Expected: Composting system established and first batch in progress.
On failure: 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).
Step 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
Expected: Soil protected year-round, biology undisturbed, organic matter increasing.
On failure: 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.
Step 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.
Expected: Preparations applied at correct time and moon phase. Soil biology activation visible over 1-2 seasons.
On failure: 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.
Step 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
Expected: Measurable improvement in at least 2 of 3 indicators (structure, biology, drainage).
On failure: 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.
Validation 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
Common Pitfalls
- Adding without testing: Random amendments waste money and can worsen imbalances. Always test first
- Rototilling: Feels productive but destroys soil structure, kills earthworms, and brings weed seeds to surface. Use a broadfork if you must loosen
- Bare soil: Exposed soil loses moisture, structure, and biology. Always mulch or plant cover crops
- Fresh manure on beds: Burns roots and introduces pathogens. Compost all manure for at least 6 months before soil contact
- Lime without testing pH: Overliming makes nutrients unavailable. Only adjust pH based on actual test results
- Expecting instant results: Soil building is measured in seasons and years, not weeks
Related Skills
cultivate-bonsai— Bonsai soil mix (akadama/pumice/lava) is a specialized soil preparationplan-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 protocolheal— Post-amendment assessment follows the heal triage patternforage-plants— Understanding soil-plant relationships aids wild plant habitat readingmake-fire— Wood ash from fire is a traditional soil amendment (potassium + lime)