Permaculturist | IT Specialist | Soil Systems Architect
Applying system engineering to organic soil biology at Evergreen Hideout Agricultural Services.
June 8, 2026 • 24 min read • Soshanguve, Pretoria"An onion is only as good as its start. Bury it wrong, and it will struggle forever. Plant it right, and it will feed you for months. The difference is 2 centimeters of depth and the discipline to check every root."
Onion Architecture: Hand-Planting Purple Seedlings into Top-Dressed Soil Armor
To maximize root expansion and bulb sizing, purple onions require deep, loose soil structure and a clean supply of balanced nutrients. Following up directly on our recent work top-dressing our intensive rows with deep, high-protein chicken feather compost (Post #13), today we are executing the physical transplant step. Operating on an absolute zero-budget framework, we are spacing out our own home-raised starts directly into our biologically active beds. This chronological checklist details the complete field workflow, showing the genuine first-hand steps of the planting run to ensure a clean, high-value presentation.
Why Purple Onions? Variety Selection and Timing
Before we get into the planting steps, let us establish why we chose purple onions and why June is the right time in Soshanguve:
- Variety: Purple onions (Allium cepa, 'Red Creole' or similar short-day variety). These are well-adapted to South African growing conditions. They require 10–12 hours of daylight to bulb — which matches our winter daylength (10.5–11.5 hours in June–July). Long-day varieties (requiring 14+ hours) would not bulb properly here.
- Flavor and storage profile: Purple onions are milder than white or yellow onions, making them excellent for fresh eating (salads, sandwiches). They store for 3–4 months when cured properly, which is shorter than yellow onions (6–8 months) but longer than spring onions.
- Winter planting window in Soshanguve: Onions are planted in autumn (March–May) or early winter (June). Our June 8 planting date is at the tail end of the window. Onions need 4–6 weeks of growth before the coldest winter temperatures arrive (July). They will grow slowly through winter, then explode in spring (September–October), bulbing in October–November for a December harvest.
- Why not earlier? Our beds were not ready. We spent March–May clearing, building soil, and establishing other crops (garlic, chard, spring onions). The compost from Post #11 and Post #12 was only finished in early June. Planting now is better than not planting at all.
Seedling Origin: Growing Our Own Starts
These onion seedlings were not purchased — they were raised on-site. Here is the timeline:
- Seed sowing (April 20, approximately 7 weeks before transplant): Seeds were sown in seedling trays filled with our homemade potting mix (50% compost from Post #3, 30% coarse sand, 20% vermiculite). Sowing depth: 1cm. Seeds germinated in 7–10 days.
- Growing conditions: Trays were kept in a shaded area (50% shade cloth) for the first 3 weeks, then moved to full sun to harden off. Watered daily (light mist). Fed once with diluted worm tea at week 4.
- Seedling selection (today): We culled any weak, leggy, or diseased seedlings. Only the strongest made it to the field. Approximately 20% were discarded — this is normal and necessary.
- Cost: 0 rands. Seeds were saved from last season's onions (we let a few bulbs bolt and go to seed). Trays and materials were reused from previous plantings. This is the zero-budget framework in action.
Step 1: Inspecting the Plant Stock Architecture
Our planting process starts with a strict quality evaluation of our resource material. As we examine the root structural health of our purple onion plugs, we look for vibrant development. The root systems are bright white, fibrous, and perfectly developed, showing zero signs of binding or stress. The green stalks are strong and pencil-thick, providing the perfect physical foundation to handle the shock of field transplanting smoothly.
Onion seedling quality checklist — what to look for:
- Root color: Bright white to cream. Brown or black roots indicate rot or disease — discard immediately.
- Root density: Fibrous, filling the plug but not circling (root-bound). If roots are circling the bottom of the cell, the seedling is stressed and may not transplant well.
- Stem thickness (neck diameter): Pencil thickness (approximately 5–8mm). Thinner than a pencil (3–4mm) means the seedling is weak and may not survive transplant shock. Thicker than 1cm means the seedling may bolt (flower) prematurely instead of forming a bulb.
- Leaf count: 3–5 true leaves. Fewer than 3 is too young. More than 5 may indicate the seedling is root-bound.
- Leaf color: Deep green with purple tint (purple onion characteristic). Pale green or yellow indicates nitrogen deficiency — feed before transplanting.
- No visible pests or disease: Check leaf axils for aphids. Check for white powdery spots (mildew). Check for brown leaf tips (fertilizer burn or underwatering).
Our batch assessment: Root color bright white, root density fibrous with no circling, stem thickness 6–8mm, leaf count 4–5 leaves, leaf color deep green with purple tint, no pests or disease — all excellent. Ready for transplant.
Step 2: Dibbling and Spacing Out the Bed Layout
Proper grid distribution is critical to prevent overlapping leaves and to ensure every single onion bulb receives adequate sunlight and food. Moving along the beds, a simple hand tool opens up systematic deep holes directly through our active top-dressed soil armor layer. Maintaining an intensive spacing strategy, we open the planting pockets roughly 10 to 15 centimeters apart to maximize our square-foot yield without compromising the final size of the bulbs.
Spacing calculations — the math of maximum yield:
- Plant-to-plant spacing: 12cm (splitting the difference between 10cm and 15cm).
- Row-to-row spacing: 25cm. This gives bulbs room to expand (5–8cm diameter) and allows space for weeding and harvesting.
- Plants per square meter: Approximately 33 onions per square meter. For our 20m² production area, that is 660 onions — enough for fresh eating and storage for 3–4 months.
- Companion integration: Onions are being planted in the gaps between existing garlic (Post #6), chard (Post #7), and spring onions (Post #8). This is intensive intercropping.
Dibbling depth — how deep to make the hole: Target hole depth is 5–6cm. Dibbling tool options include a wooden dowel, broken broom handle, or commercial dibber. Our tool is a homemade dibber from a recycled metal rod with a wooden handle — cost nothing.
Step 3: Setting the Seedlings into the Root Zone
With our grid architecture opened up, we begin setting the individual plants. Each purple seedling is dropped carefully into its designated hole. It is essential to ensure the roots go straight down without bending upward or "J-rooting," which would stunt early growth. Setting them firmly at the exact depth of their true crown ensures they stand stable against wind while keeping the delicate base tucked safely into our nutrient-dense compost layer.
The danger of J-rooting: When the root tip bends upward at the bottom of the hole, forming a "J" shape, the bent root tip will try to grow upward, emerging from the soil surface or tangling with other roots. J-rooted onions are stunted, produce smaller bulbs, and are more susceptible to disease. Prevention: Make holes deep enough (5–6cm). Hold the seedling by the leaves (not the roots) and lower it gently. Do not push or jam the seedling into the hole.
Planting depth — the crown rule: The crown is the point where the roots meet the stem (the white bulb section). Plant so the crown sits just below the soil surface (approximately 1cm deep). If planted too shallow (crown exposed), the bulb will turn green and become tough and woody. If planted too deep (crown buried more than 2cm), the stem may rot, especially in wet winter conditions.
Step 4: Firming and Tucking the Bed Shoulders
Once the plugs are seated, the soil around the base must be settled manually to optimize root contact and eliminate air pockets. The initial lines of our newly transplanted seedlings stand perfectly straight along the shoulders of the raised row. The surrounding earth is pressed gently to anchor them firmly, allowing the emerging roots to instantly tap into the soil biology without drying out.
Firming technique: Use your fingers (not your whole hand) to press soil gently around each stem. Press just firmly enough to close the hole and eliminate air pockets — not so firmly that you compact the soil. Test: After firming, gently tug on a leaf. The seedling should not lift out of the ground.
Mulch management after planting: After firming the soil, pull the compost layer (from Post #13) back around the stem, leaving a 2–3cm clear zone (the "donut hole"). Do not pile compost directly against the stem — this causes rot and attracts pests.
Step 5: The Post-Planting System Review
Our field run concludes with a full visual audit of the intensive planting section. Looking at the final layout under the sun, every seedling row is fully stabilized, balanced across the contours of our beds, and neatly insulated by our low-budget compost mulch layer. This complete setup forms a powerful biological defense that blocks out competing weed seeds and retains moisture through our dry weather cycles.
Post-planting audit checklist (24 hours after planting): Seedlings should be standing straight (not flopped over). Leaves should be turgid, not wilted. No exposed roots should be visible on the soil surface. Crown depth should be approximately 1cm below surface. Compost should not be touching stems. Spacing should be consistent (no overcrowding).
Step 6: Settling the Beds with Immediate Irrigation
The final and most critical step of the transplant day is the initial soaking. Holding the hose pipe, I apply a gentle, steady stream of water across the newly established rows. This deep irrigation run settles the loose soil around the roots, collapses hidden air pockets, and instantly activates the microbial life within our feather compost. Ensuring a consistent, non-eroding moisture flow sets up the perfect environment for these purple alliums to push past transplant shock and kickstart rapid development.
Post-planting watering protocol — the initialization sequence:
- Water immediately after planting. Do not wait. Roots dry out within minutes in Soshanguve's low-humidity air (25–35% in winter).
- Water volume: 0.5–1 liter per square meter (approximately 0.5 liters per 10 seedlings). This is enough to settle the soil but not so much that it washes the compost away.
- Water temperature: Room temperature (18–22°C). Cold tap water (10–12°C in winter) shocks roots, slowing establishment by 3–5 days.
- Application method: Gentle stream from a hose with a soft spray nozzle or watering can with a rose. Do not use a jet nozzle — it will wash soil away from the roots.
- Water quality: If using municipal tap water, let it sit for 24 hours to off-gas chlorine (chlorine kills soil bacteria).
- Second watering: Do not water again for 3–5 days unless the soil surface is completely dry. Overwatering is the #1 killer of transplanted onions.
Why This Planting Architecture Works
- Loose Root Channels: Dibbling precise deep pockets avoids compacting the surrounding soil, allowing the delicate new white onion roots to spread out freely without burning extra energy. Compacted soil would force roots to push harder, delaying establishment by 5–10 days.
- Integrated Compost Shield: Placing our starts right into the feather-amended soil beds gives the alliums an immediate biological advantage, pushing fast early leaf growth which directly determines final bulb size. Onion bulb size is determined by leaf number at bulbing — more leaves = larger bulbs.
- Zero-Rand Execution: By saving our own seed stock, raising our own starts, and top-dressing with free local waste inputs, we create high-value market crops completely free of debt. A single bunch of purple onions at the Soshanguve market sells for R15–25. With 660 onions, that is R9,900–16,500 of potential value from zero cash input.
- Winter Planting Advantage: Onions planted in winter grow slowly at first but develop deep root systems before spring. When daylength increases in September–October, those deep roots fuel rapid leaf growth and bulb expansion.
- Immediate Irrigation Activation: Watering immediately after planting collapses air pockets, settles soil around roots, and activates the microbial life in the feather compost — giving the seedlings a running start.
Integration with the Series
- Post #1 (Solarization) & Post #2 (Initial Clearing): Cleared the land for our beds.
- Post #4 (Soil Architecture): Built the raised beds and amended the soil.
- Post #5 (Mulch Firewall): Established the mulch layer that still protects our beds.
- Post #6 (Garlic), Post #7 (Chard), Post #8 (Spring Onions): Established our first crops.
- Post #11 (Compost Pile) & Post #12 (Feathers): Created the compost that top-dressed the beds.
- Post #13 (Applying Compost): Top-dressed the beds with feather compost.
- Post #14 (This post — Planting Onions): Planted purple onion seedlings into the compost-amended beds and irrigated immediately.
- Post #15 (Upcoming — Cauliflower Seedlings): We will plant cauliflower seedlings into the remaining bed space.
Failure Mode Analysis: Onion Transplanting Edition
Failure 1: J-rooting (roots bend upward, seedling struggles). Cause: Hole too shallow, or seedling pushed in rather than dropped. Recovery: Gently pull the seedling, dig a deeper hole, and replant. Prevention: Make holes 5–6cm deep. Drop seedlings gently — do not force them.
Failure 2: Crown rot (stem turns brown and mushy at soil line). Cause: Crown planted too deep (more than 2cm below surface), or compost piled against stem. Recovery: Remove affected seedlings — they will not recover. Prevention: Plant crown 1cm below surface. Leave 2–3cm clear zone around stem.
Failure 3: Seedlings dry out and die within 24 hours. Cause: Roots dried out during planting, or no water applied immediately after. Recovery: None. Prevention: Keep seedling tray moist and shaded during planting. Water immediately after planting each batch.
Failure 4: Birds pull seedlings out of the ground. Cause: Birds (hadedas, doves) see exposed seedlings as food. Recovery: Replant immediately and cover with bird netting. Prevention: Apply bird netting for the first 3–5 days after transplanting.
Failure 5: Spacing is inconsistent (some seedlings too close, some too far). Cause: No measuring tool used. Recovery: Thin overcrowded seedlings after they establish. Prevention: Use a string line or planting stick marked with 12cm intervals.
What's Next?
Now that our purple onion plot is fully installed, stabilized, and thoroughly irrigated, we turn our attention to the next crop in our planting sequence.
The upcoming post will be about planting cauliflower seedlings.
Cauliflower is a cool-season brassica that thrives in Soshanguve's winter temperatures (15–22°C days, 5–10°C nights). It is a heavy feeder that will benefit enormously from the same feather compost layer we applied to the onion beds. By planting cauliflower now (early June), we can expect heads to form in late August to September — just as our onions begin their spring growth spurt.
The next post will cover:
- Cauliflower variety selection: Choosing varieties that perform well in South African Highveld winters (e.g., 'Cheddar' or 'Snowball').
- Seedling preparation: How to harden off cauliflower starts (they are more sensitive to cold than onions) and what to look for in healthy transplants (stocky stems, 4–6 true leaves, no yellowing).
- Spacing requirements: Cauliflower needs significantly more space than onions — 45–60cm between plants and 60cm between rows. We will plant them in the widest gaps of our beds.
- Companion considerations: Cauliflower is in the brassica family (cabbage, broccoli, kale). It should not be planted where other brassicas grew recently (disease rotation). Our beds have not hosted brassicas, so they are clean.
- Planting depth and technique: Cauliflower seedlings should be planted slightly deeper than they were in the tray (to cover the lower stem) to encourage stability. Unlike onions, they benefit from soil mounded around the stem.
- Immediate aftercare: Watering in (same protocol as onions — room temperature water, gentle stream), and protecting from cutworms (which love brassicas) using cardboard collars or diatomaceous earth.
- Expected timeline: Cauliflower takes 60–90 days from transplant to harvest depending on variety and temperature. June planting means August–September harvest — perfect timing before summer heat causes bolting.
Adding cauliflower to our winter garden diversifies our harvest and makes full use of our compost-amended beds. While onions store for months, cauliflower provides fresh, nutrient-dense harvests in late winter when few other crops are producing. Together, they create a complete winter production system.
Stay tuned for the next update from Soshanguve. Keep your hands in the soil and your logs updated.
If you are just joining the Real Grow series, catch up here:
Post #2: The Tool Logic – Land Clearing & Pick-Mattock Technique
Post #3: Below the Surface: The Masterclass on Soil Turning and Root Extraction
— Kutlwano
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