Leek seedling mastery begins with choosing high-quality seeds and sowing them in seed trays or pots, ensuring they’re kept moist and at a warm temperature until they germinate. Once the seedlings grow a few inches tall, it’s important to thin them out, so they have enough space to develop strong roots. When handling seedlings, be gentle to avoid damaging their delicate stems and roots. Transplanting comes next; when the seedlings have a few true leaves and the weather is right, prepare the garden bed by loosening the soil and adding some compost. Carefully remove the seedlings from their trays, ensuring you keep as much of the root system intact as possible, and plant them in rows about six inches apart, covering the roots with soil. After transplanting, water them well and keep the soil consistently moist as they settle into their new home, leading to healthy, long white shafts of leeks ready for harvest.
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July 2, 2026 • 22 min read • Soshanguve, Pretoria"Leeks teach you about depth. Plant them shallow, and you get thin, green disappointment. Plant them deep, and they reward you with long, white shafts that make every soup better. The same is true for roots in life."
Leeks: Propagating, Handling, and Transplanting for Long White Shafts
Transitioning leek seedlings from their crowded nursery stage into permanent beds is a critical step that requires careful handling. Today, we are breaking down the exact step-by-step method used at Evergreen Hideout to prepare, separate, and plant out these seedlings to ensure a high survival rate this winter.
Leeks are a versatile, cold-hardy crop that deserves more attention in South African winter gardens. They are relatives of onions and garlic but with a milder, sweeter flavor. They store well, are easy to grow, and command a premium price at markets. This post covers the complete process from seedling management to transplanting into our permanent beds.
Why Leeks? Variety Selection and Winter Timing
Before we get into the planting steps, let us establish why we chose leeks and why July is the right time in Soshanguve:
- Variety: 'Winter Giant' or 'Musselburgh' (hardy, thick-stemmed varieties). These are cold-tolerant and can withstand temperatures down to -5°C. They are ideal for Gauteng winters.
- Why leeks instead of more onions? Leeks offer a different flavor profile and are less common in home gardens, which means higher market value. They also store well in the ground (you can harvest as needed over winter).
- Winter planting window in Soshanguve: Leeks can be planted from May through August. Our July 2 planting date is well within the window. Leeks take 60–90 days to mature from transplant, which means a September–October harvest — perfect for spring markets.
- Temperature tolerance: Leeks thrive in cool weather (10–22°C) and can survive light frost. Our winter temperatures (2–10°C nights, 10–22°C days) are ideal.
- Why not earlier? Our beds were occupied with other crops (garlic, chard, onions, cauliflower, kale). The leek seedlings have been waiting in the nursery trays for approximately 8 weeks — they are now at the perfect transplant size.
Seedling Origin: Growing Our Own Leek Starts
These leek seedlings were not purchased — they were raised on-site. Here is the timeline:
- Seed sowing (May 5, approximately 8 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.
- Cost: 0 rands. Seeds were saved from last season's leeks (we let a few plants bolt and go to seed). Trays and materials were reused from previous plantings.
Step 1: Staging the Nursery Block
As seen in the image, before any separation begins, we keep the entire seedling block well-hydrated right next to our white watering can. Keeping the soil damp makes separating the tightly intertwined root masses significantly easier and minimizes structural damage to the fine root hairs.
Leek 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). Leek roots are thick and fleshy compared to onion roots.
- Stem thickness: Pencil thickness (approximately 5–8mm). Thinner than a pencil (3–4mm) means the seedling is weak.
- Leaf count: 4–6 leaves. Fewer than 4 is too young. More than 6 may indicate the seedling is root-bound.
- Leaf color: Deep green with no yellowing or tip-burn. Pale green indicates nitrogen deficiency.
- No visible pests or disease: Check leaf axils for aphids. Check for white powdery spots (mildew).
Our batch assessment: Root color bright white, root density fibrous (handle carefully), stem thickness 6–8mm, leaf count 5–6 leaves, leaf color deep green, no pests or disease — all excellent. Ready for transplant.
Keeping roots moist — the critical rule:
- Leek roots are thick and fleshy, but they dry out quickly when exposed to air.
- Keep the seedling bundle in a shaded, moist environment while separating plants.
- Work in batches of 10–15 seedlings at a time. Do not pull out all seedlings at once.
- If roots dry out, soak them in water for 10 minutes before planting to rehydrate.
Step 2: Handling the Seedling Bunches — Selection and Teasing Apart
Next, we break down the main block into smaller working groups. Looking at the image, we tease out a manageable bunch of seedlings to prepare them for individual planting along the rows. Handling them carefully with gloves prevents bruising the tender green stems.
Separation technique — the gentle tease:
- Hold the seedling bundle at the base (near the roots), not the leaves.
- Gently pull the bundle apart, starting from the outside edges.
- Do not tear or rip — if a seedling resists, leave it and come back to it after removing the surrounding seedlings.
- The goal is to keep each seedling's root system as intact as possible. Broken roots reduce transplant success.
- If the roots are tangled, soak the bundle in water for 5 minutes before separating — the water loosens the soil and makes separation easier.
Seedling preparation before planting:
- Trim the roots slightly (to 3–4cm) if they are very long (over 10cm). This encourages new root growth after transplanting.
- Trim the leaves slightly (to 10–15cm) if they are very long (over 20cm). This reduces water loss during transplant shock.
- Do not trim the white stem — this is the edible part.
Our seedlings: Roots were 5–8cm long — we did not trim. Leaves were 15–20cm long — we did not trim. The seedlings were ready to plant as-is.
Step 3: Clearing the Planting Zone — Bed Preparation
With our seedling bunches ready, we move down the prepared bed channels. As shown in the image, we work methodically through the chicken feathers compost layer to create small planting pockets, ensuring each root system drops straight down into the rich soil matrix below.
Bed preparation protocol:
- Mulch removal: Pull back the mulch layer (Post #5) to expose a 15cm-wide strip of soil. Do not remove the mulch entirely — just push it aside temporarily.
- Soil loosening: Use a hand trowel or garden fork to loosen the top 10–15cm of soil. Leeks need loose soil to develop long white shafts.
- Compost incorporation: The chicken feather compost (Post #13) is already in place, providing slow-release nutrition.
- Furrow creation: Create a shallow furrow (5–10cm deep) along the row using a trowel or hoe. This gives the leeks a head start on blanching.
Why depth matters for leeks — the blanching effect:
- Leeks produce long, white shafts when the stem is kept away from light. The white part is the edible section.
- Planting leeks deep (5–10cm) ensures that the lower stem is buried, preventing light from reaching it.
- As the leek grows, you can mound soil around the stem to extend the white shaft.
- A longer white shaft = higher market value and more edible product per plant.
Step 4: Inspection of the Newly Set Leek — Depth and Spacing
Once tucked into its permanent spot, as captured in the close-up image, the young leek stands stable in the dark earth, securely surrounded by protective chicken feathers compost. While they look incredibly delicate and can loop or curve early on, they quickly straighten out as they anchor and establish.
Planting depth — the key to long white shafts:
- Target depth: 5–10cm deep (the white stem should be buried so only the green leaves are visible).
- How to achieve depth: Dig a hole 5–10cm deep using a dibber or trowel. Drop the seedling in so the split between roots and stem is 5–10cm below the soil surface.
- Why deep planting works: The buried stem will etiolate (grow long and white) as it reaches for light. This is how leeks develop their prized long white shafts.
- If planted too shallow (under 5cm): The shaft will be short and green. Market value is lower.
- If planted too deep (over 15cm): The stem may rot in wet soil.
- Our planting depth: 8–10cm — ideal for long white shafts.
Spacing calculations — leeks need room to thicken:
- Plant-to-plant spacing: 10–15cm. Leeks grow upright and do not spread much, so they can be planted closer than onions.
- Row-to-row spacing: 30cm. This gives the leeks room to thicken and allows space for weeding and harvesting.
- Plants per square meter: Approximately 30–40 leeks per square meter (at 15cm spacing).
- Our spacing: 12cm between plants, 30cm between rows — approximately 33 plants per square meter.
Firming technique — how to set the seedling:
- After placing the seedling in the hole, backfill with soil.
- Press the soil gently around the stem — do not compact.
- Test: Gently tug on a leaf. The seedling should not lift out.
- Do not press soil into the "V" where the leaves split — this can cause rot.
Step 5: Settling the Beds with Targeted Irrigation
To finalize the planting loop, immediate watering is required to eliminate air pockets around the newly moved roots. In the video demonstration, we stand in the rows using a garden hose to apply a controlled stream across the organic compost beds, ensuring deep moisture penetration without flattening the young, fragile plants.
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.
- Water volume: 1–2 liters per plant (depending on soil moisture). Leeks need consistent moisture during establishment.
- Water temperature: Room temperature (18–22°C). Cold tap water (10–12°C in winter) shocks roots.
- Application method: Gentle stream at the base of each plant. Keep water pressure low so you don't uproot or wash away the tiny seedlings.
- Water quality: If using municipal tap water, let it sit for 24 hours to off-gas chlorine.
- Second watering: Do not water again for 3–5 days unless the soil surface is completely dry. Overwatering causes root rot.
Mulch management after planting:
- After watering, pull the mulch layer back around the stems, leaving a 2–3cm clear zone (the "donut hole").
- Do not pile mulch directly against the stem — this causes rot and attracts pests.
- The mulch layer should be 8–10cm thick, tapering to 2cm near the stem.
Key Lessons from the Leek Plot
- Root Hydration: Never let separated seedlings sit exposed to the dry winter wind; keep them damp until the moment they go into the ground. Leek roots dry out faster than onion roots.
- Compost Protection: Keeping the chicken feathers compost (Post #13) tucked neatly around the base helps regulate soil temperature during freezing Soshanguve winter nights while feeding the soil biology. The compost also provides slow-release nitrogen for steady growth.
- Gentle Flow: When using a hose pipe, keep the water pressure low so you don't uproot or wash away the tiny seedlings before they establish. A gentle shower head attachment is ideal.
- Blanching Potential: Planting leeks at 8–10cm depth gives us a head start on blanching. As the leeks grow, we will mound soil around the stems to extend the white shaft further.
The Blanching Process: Extending the White Shaft
Leeks are valued for their long white shafts. The white part is the stem that has been kept away from light. Here is how we manage blanching:
- Initial planting depth (this post): 8–10cm deep. This buries the lower stem, starting the blanching process immediately.
- Mounding (hilling) — 4–6 weeks after planting: As the leek grows, we will mound soil around the stem to extend the white shaft. This is done twice during the growing season.
- Mounding technique: Gently pull soil from between the rows up around the stems, covering the lower 5–10cm of the green leaves. This forces the stem to elongate further.
- Mulch blanching: Instead of soil, we can use mulch (straw or dry grass) to blanch the stems. This is lighter and easier to manage.
- Why blanching matters: A longer white shaft = more edible product per plant = higher market value. Leeks with 15–20cm white shafts sell for a premium; leeks with 5–10cm white shafts sell for less.
- When to stop blanching: Stop mounding 3–4 weeks before harvest to allow the stems to firm up.
Failure Mode Analysis: Leek Transplanting Edition
Failure 1: Seedlings wilt and die within 48 hours. Cause: Roots dried out during planting, or no water applied immediately after. Recovery: None — dead seedlings cannot recover. Prevention: Keep seedling tray moist and shaded during planting. Work in batches of 10–15 seedlings at a time. Water immediately after planting each batch.
Failure 2: Stems rot at the soil line (soft, brown, mushy). Cause: Planted too deep (over 15cm), or mulch piled against the stem, or overwatering. Recovery: Remove affected seedlings — they will not recover. Prevention: Plant at 8–10cm depth. Leave 2–3cm clear zone around stem. Water only when the top 2cm of soil is dry.
Failure 3: Leeks produce short, green shafts (small white part). Cause: Planted too shallow (under 5cm), or not mounded during growth. Recovery: Mound soil immediately to cover the lower stem. The white shaft will extend over the next few weeks. Prevention: Plant at 8–10cm depth initially. Mound soil twice during the growing season.
Failure 4: Leaves have rust-colored spots (leek rust). Cause: Fungal disease common in wet or humid conditions. Recovery: Remove affected leaves. Apply milk spray (40% milk, 60% water) every 5 days. Prevention: Water at the base of plants, not overhead. Ensure spacing is at least 10cm between plants for airflow.
Failure 5: Seedlings are attacked by onion flies or thrips. Cause: Pests attracted to alliums. Recovery: Spray with soapy water (1 teaspoon castile soap per liter) every 3 days until pests are gone. Prevention: Plant garlic or onions nearby — alliums repel pests. Use floating row cover for the first 2 weeks after transplanting.
Integration with the Series
- Post #5 (Mulch Firewall): The mulch layer that is protecting our leek seedlings.
- Post #9 (Weed Management): Weeding protocol that keeps the leek beds clean.
- Post #13 (Feather Compost): The top-dressing that provided slow-release nutrition for the beds.
- Post #19 (This post — Leek Transplanting): Planting leek seedlings into the compost-amended beds.
- Post #20 (Upcoming — Spring Onion Update): We will provide a growth update on our spring onions.
Seasonal Timing: Why July 2 Works for Leeks
In Soshanguve, leeks can be planted from May through August. Our July 2 planting date is well within the window. Here is the analysis:
- Advantage: Leeks grow best in cool weather (10–22°C). Soshanguve's July temperatures (10–22°C days, 2–10°C nights) are ideal. Leeks can survive light frost without damage.
- Risk: Leeks planted in July may have a shorter growing period before spring heat arrives. However, leeks are slow-growing and can tolerate some heat.
- Mitigation: Our mulch layer (Post #5) insulates the soil, keeping roots cool. We will provide consistent moisture to prevent heat stress.
- Expected harvest: September–October 2026 (60–90 days from planting). This is ideal for spring markets.
- Continuous harvest: Leeks can be left in the ground and harvested as needed over 2–3 months.
What's Next?
We will monitor this new bed over the coming weeks to watch the stems begin to thicken up.
The next post will be about a Spring Onion update.
Back in Post #8, we planted our spring onions (the "Middleware Layer" protocol). It has now been approximately 8 weeks since planting (May 7 to July 2). The spring onions have gone through their initial establishment phase, and it is time to provide a full growth update — including how they have responded to the fish fertilizer (Post #10), the feather compost top-dressing (Post #13), and the winter conditions in Soshanguve.
The next post will cover:
- Growth metrics: Current plant height, leaf thickness, and overall health compared to the planting date. We will measure leaf length, number of leaves per cluster, and stem diameter.
- Harvest update: We have been harvesting spring onions on a cut-and-come-again basis. How many harvests have we taken? How much total weight per cluster? How quickly do they regrow?
- Response to fish fertilizer (Post #10): Spring onions are light to moderate feeders. We have been applying fish fertilizer every 14 days. How has the crop responded? Are the leaves darker green? Is growth faster?
- Response to feather compost top-dressing (Post #13): We applied feather compost to the spring onion beds on June 5. Has there been a visible growth response in the 4 weeks since?
- Winter performance: Spring onions are cold-hardy but grow slowly in winter. How are they handling Soshanguve's winter temperatures (10–22°C days, 2–10°C nights)? Have we seen any frost damage?
- Pest and disease check: Have we seen any onion flies, thrips, or fungal diseases on the spring onions? How are we managing them?
- Comparison to other alliums: How do spring onions compare to garlic (Post #6) and leeks (Post #19) in terms of growth rate and cold tolerance?
- Future plans: When will we plant the next succession of spring onions? Will we continue harvesting the existing plants or replace them?
This spring onion update will complete our mid-season audit of all the allium crops in our system — garlic (Post #6), spring onions (Post #8), and leeks (Post #19). Together, these updates will give us a comprehensive picture of how our allium family is performing through the winter months.
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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