How to Grow Lemongrass from Seed in South Africa
Grow a fragrant lemongrass clump for your sunny herb garden, starting with seed. This guide explains how to give seedlings a warm, gentle start, make room for mature growth and protect plants when South African winters turn cold.
Start with the right kind of lemongrass. These seeds are listed as East Indian lemongrass, Cymbopogon flexuosus. Grow it for aromatic foliage and leaf stalks; thick supermarket-style stem bases often associated with C. citratus are not guaranteed. Rooting bought stalks is a different starting method.
Lemongrass from seed: quick grow facts
Choose your Lemongrass Seeds pack for seed-grown Cymbopogon flexuosus from Ubuntuberg. The pack choices are 5 cleaned seed, 100 raw seed and 1000 raw seed. No named cultivar or series is confirmed.
Plant and position
A clump-forming perennial grass in a warm, frost-free garden; grow seasonally or protect it in colder places. Choose full sun and a warm, sheltered position.
Seed and warmth
Cleaned and raw describe the listed seed forms, not treatment status. A protected tray start makes moisture easier to manage. General lemongrass guidance uses a warm medium around 20–25°C.
Mature size and space
Foliage commonly reaches about 90–150 cm. Missouri Botanical Garden lists 60–90 cm spread; the RHS species profile allows 1–1.5 m. Start with 60–90 cm garden spacing and leave more room for older clumps to broaden.
Harvest stage
Pick lightly only once the clump is well rooted and growing strongly. Leaf picking and removal of whole outer leaf stalks are different demands on a young plant; build the clump before taking more.
Choose a shallow sowing method. The shop's displayed 100-seed label gives a depth of 5 mm. Kings Seeds also specifies approximately 5 mm for East Indian lemongrass, with a thin covering and light. Johnny's instead recommends surface sowing or light cover because light helps germination. These are different published methods, not evidence that 5 mm is always wrong. The tray steps below use the surface-or-light-dusting method. Keep the medium gently moist and follow any treatment precautions on your packet.
Give seed a warm, lightly covered start
- Use clean small pots or cells with drainage holes and fresh, fine seed-sowing medium. Moisten the mix before sowing; it should be damp and airy, not muddy.
- For the general seed-grown method, distribute seed thinly on the surface and press it into contact. Use no more than a very light dusting of fine medium. Do not bury it under a heavy layer or keep the tray in darkness.
- Keep the medium warm and gently moist. A clear cover can reduce drying before emergence; ventilate it and keep it out of fierce direct sun. Avoid a sealed, overheated tray.
- Once seedlings emerge, give them bright light and gradually remove the cover. Water gently without leaving the pot standing in water.
How long? Johnny's reports 7–14 days for its cleaned East Indian seed at about 20°C, or 20°C nights and 30°C days. Kings Seeds gives 21–40 days at 21–24°C. The RHS general guide gives 2–3 weeks at 20–25°C, while its species profile suggests a cooler 13–18°C start. The shop label says 20–30 days without a temperature. These are separate reference conditions, not a combined germination guarantee for the cleaned and raw packs. For a protected warm start, use the method above, track medium temperature and moisture, and allow for uneven emergence.
Do not rub, soak, scarify or chill the seed yourself without instructions for your pack. A supplier description of seed being cleaned or rubbed during processing is not a request to repeat that treatment.
Trays are the practical first choice. Move seedlings into a larger cell or pot as roots fill their space. Around 8–10 cm tall is a useful transplant guide, provided roots hold the plug together and the plants are healthy. Harden off gradually, then plant at the same soil level after frost danger has passed and growing conditions are warm. Direct sowing is a small-trial option only where a warm, fine seedbed can stay reliably moist; thin crowded seedlings before roots become tangled. A protected start avoids many weather and weed problems.
Leave room for a spreading clump
The shop label lists 45–60 cm spacing. For plants kept for several seasons, 60–90 cm is a practical starting allowance based on Missouri Botanical Garden's spread, with access between clumps. The RHS species profile lists a larger 1–1.5 m spread, so leave extra room where clumps can develop over time. This garden allowance is a planning adaptation, not a new packet instruction. Flowering stems can rise above the leafy clump.
Johnny's uses a closer 20–30 cm spacing with rows about 45 cm apart for its seed-grown crop. Treat this as a separate intensive seasonal trial, not the permanent-clump layout or a proven yield system for these packs. In damp sites, prioritise airflow and access. Decorative cut-flower row spacing is not applicable to this herb.
For pots, choose a stable container with drainage holes and room to pot on. A small starter pot will not accommodate a mature clump. Leave space to move it into shelter before winter; avoid a container so heavy that your cold-weather plan becomes impractical.
Choose a growing window for your South African region
These are practical adaptations to local heat, rainfall and frost, not results from trials of this seed lot. Use your garden's conditions and the forecast rather than one national sowing month.
Winter-rainfall Western Cape
Start in spring under protection as warmth returns. Plant out when the bed drains freely and late frost is unlikely. Summer wind and dry weather can empty pots quickly. Keep overwintering crowns out of saturated winter soil; a movable pot is useful in cold or wet gardens.
Frost-prone interior
Raise seedlings in warmth before outdoor planting conditions arrive. Plant after the last local frost, leaving a long warm season for clump growth. Plan protection early: move a pot into bright, frost-free shelter or grow it as a seasonal herb. Do not count on frost-damaged crowns surviving.
Humid coast and KZN Midlands
A frost-free coast offers a longer growing season, but wet summers call for drainage and space between clumps. Avoid sowing into pounding rain. Frosty Midlands sites need the interior approach; coastal advice is not a reliable winter plan higher up.
Hot-dry or subtropical interior
Choose a warm period when irrigation is dependable, avoiding peak heat for exposed seed trays. Protect emerging seedlings from drying wind and introduce full sun gradually. Subtropical sites can retain clumps where winters stay mild; colder inland pockets still need frost protection.
Water, feed and protect the growing clump
Keep the root zone moist during establishment, then water in response to the soil, rainfall and growth. Check pots frequently in hot weather. Use freely draining soil with modest compost where needed, and keep mulch away from the crown. Persistent standing water is a drainage problem, not a cue to feed.
Feed container plants during active growth with a suitable general-purpose fertiliser at its label rate. Pause feeding when growth slows in cold conditions. No pinching or routine staking is required to form the grassy clump; choose shelter from damaging wind and remove damaged foliage with clean tools.
Before cold weather, move container plants into a bright, frost-free place. Water less as growth slows, without letting the root ball become completely dry. Trim dead leaves carefully as warmth and new growth return. Division is an option for an established crowded clump later, but it does not replace the seed-starting instructions above.
Inspect leaves for rust-like spotting and indoor plants for fine webbing or mites. Separate affected pots, remove badly damaged foliage and improve growing conditions. Confirm the cause before using a treatment; follow a product label that allows the crop and intended harvest, including any waiting period. Do not substitute household spray recipes.
Pick leaves first, then spare outer stalks
Light leaf picking: wait for a vigorous, well-established clump, then take a small amount of outer foliage while leaving plenty of green growth. A seedling with only a few blades needs time to build roots.
Outer leaf stalks: harvest sparingly from the edge once the clump has enough shoots to spare. Avoid pulling apart its young centre. Johnny's lists 75–85 days from sowing for its cleaned East Indian seed, which is a useful comparison rather than a tested schedule for these packs. The shop's 75–100-day figure does not define its starting point or harvest stage. Judge readiness by sturdy growth, not a fixed deadline; cold starts, small pots and moisture stress can delay useful harvests.
Use the aromatic foliage or fibrous leaf stalks to infuse food, then remove tough pieces before serving. This species can flavour soups and curries, but a seed-grown clump is not a guarantee of supermarket-style swollen stems. Rinse harvested material and use clean tools. Flowering is not needed for a leaf harvest and may be absent in a short season.
When seeds or young plants struggle
Nothing emerges
Check actual medium temperature, excessive cover and whether the surface dried out. Cold, saturation or damaged seed can also be involved. Record sowing conditions and contact the supplier about the lot before repeating the same method with all remaining seed.
Seedlings collapse at soil level
Damping-off is a possible cause, especially in wet, crowded trays. Remove failed seedlings, clean containers and restart with fresh medium if needed. Improve drainage and ventilation; more fertiliser will not repair a rotted stem.
Growth stalls after transplanting
Check cold nights, disturbed roots, a buried crown or abrupt sun and wind exposure. Keep the root zone gently moist and protect the plant while it recovers. Next time plant healthy plugs after gradual hardening off.
Yellow or brown leaves
Inspect moisture and drainage before assuming a nutrient shortage. Dry pots, saturated roots and cold can look similar. Look closely for rust spots or pest damage; seek a diagnosis if the cause remains unclear.
No thick stalks to harvest
Check the species and stage: C. flexuosus is being grown for aromatic foliage and leaf stalks here. Give the clump time, warmth and space. Extra fertiliser cannot make it a different species.
Brown growth after winter
Frost can kill leaves and may kill the plant. Do not assume a crown will recover. Keep surviving plants out of waterlogged soil and look for new shoots as warmth returns; replace a dead plant and improve protection next season.
Handle seed and sharp leaves with care
Do not eat sowing seed or use it for sprouts, microgreens or animal feed. Neither raw nor cleaned proves untreated or food-grade status. Follow the current packet's treatment and crop-use precautions, and ask for the lot declaration if these are missing. Keep seed labelled and away from children and pets; wash after handling. Washing seed is not a treatment-removal method.
Mature leaf edges can cut skin: wear gloves when handling or trimming a clump. Kitchen use applies to appropriately grown, correctly identified plants, not every grass with a lemon scent. No medicinal use, essential-oil ingestion, pet-safe status or insect-repellent performance is claimed.
Planning your herb bed? View Lemongrass Seeds and choose a pack for your next sowing. Keep the packet with your sowing notes so you can follow the right instructions as the clump develops.
Growing references and packet notes
Product identity and displayed packet figures come from GARDENING.co.za's current listing and Ubuntuberg's Lemongrass listing. Sowing alternatives are also documented by Kings Seeds' East Indian lemongrass instructions; the named maturity comparison comes from Johnny's cleaned-seed timing reference. General guidance is cross-checked with Johnny's seed-grown East Indian lemongrass instructions, the RHS lemongrass guide, the RHS East Indian species profile and Missouri Botanical Garden's species profile. The RHS general guide includes other lemongrass, so its swollen-stem harvest advice is not used as a promise for these seeds.
University of Maryland Extension and University of Minnesota Extension inform the general seedling checks. NPIC explains treated-seed precautions. A current physical packet, lot test, treatment declaration and exact supplier depth/harvest clarification have not been supplied; the displayed label is not a lot certificate.