A lemon seed is an inexpensive way to experiment with growing citrus. Save a few from a fresh fruit, sow them in a small pot and you may eventually have a glossy evergreen plant on a sunny windowsill. Growing an actual crop of good lemons is a different challenge.
Seed-grown citrus can take years to reach maturity, and the fruit may not be identical to the lemon you bought. In Britain, the main obstacles are winter light, warmth and the need to protect citrus from frost. If you approach it as a houseplant experiment first, it's much more rewarding.
Start with fresh viable seeds
Choose a sound ripe lemon and remove several plump seeds. Not every seed will germinate, so starting a few improves your chance of success.
Rinse away sticky fruit pulp. Handle the seeds gently rather than scraping away everything that looks like a skin.
Avoid using seeds that have dried out completely for a long time. Fresh seed is often a better starting point for many citrus types.
Understand that seedlings vary
Some citrus can produce seedlings with similar characteristics to the parent, but seed propagation doesn't guarantee an identical named commercial cultivar.
Commercial lemon trees are commonly grafted onto selected rootstocks for predictable growth and performance. A random supermarket lemon seed doesn't provide those assurances.
Enjoy the learning process. If your goal is reliable fruit, buying an appropriately grafted citrus plant may be more practical.
Choose suitable seed compost
Fill a small pot or module with clean free-draining seed compost. Use a container with drainage holes.
Moisten the compost before sowing, then allow excess water to drain. It should feel evenly damp rather than swampy.
Don't use heavy compacted garden soil in a tiny indoor pot. Poor drainage can encourage seeds to rot before roots establish.
Sow at a modest depth
Place the seed in the compost and cover lightly according to citrus propagation guidance, usually around one centimetre or so depending on seed size.
Firm gently so the seed has contact with moist compost. Mark the pot with the date and 'lemon'.
Avoid burying it at the bottom of a deep wet pot. A seed needs oxygen and a realistic route to the surface.
Provide warmth for germination
Citrus seeds generally germinate better in warmth. Place the pot in a bright warm area out of cold draughts.
A propagator can help maintain temperature, but it must not overheat or trap excessive condensation. Ventilate as recommended.
Don't place a plastic-covered seed pot directly against a powerful radiator. The compost can overheat and dry unevenly.
Wait for seedlings
Germination may take several weeks and vary between seeds. Keep the compost lightly moist during this period.
Resist digging into the pot every few days to check progress. Small emerging roots can be damaged by repeated disturbance.
If some seedlings appear earlier than others, give them good light and continue caring for the remaining pots within a reasonable germination window.
Thin carefully if several emerge
More than one seedling may appear in a pot. Allow them to develop a little before deciding whether to separate or remove weaker plants.
Lift seedlings with the root ball where possible, avoiding damage to delicate stems. Don't pull hard through tangled roots.
One sturdy seedling in a small pot is easier to manage than several competing for the same limited compost and light.
Give citrus bright light
Young lemon plants appreciate good light. In Britain, a bright south-facing window or suitably sheltered conservatory may work, although intense summer sunlight through glass can scorch leaves.
Rotate the plant occasionally to encourage even growth. Keep it away from cold window glass during winter nights.
Low light can make growth thin and weak. Additional warmth without sufficient light isn't a substitute for suitable conditions.
Use citrus-appropriate compost when repotting
Once roots begin filling the small pot, move the plant into a slightly larger container with suitable free-draining growing medium.
The RHS recommends appropriate citrus compost and careful feeding for established citrus plants. Avoid sudden jumps to enormous pots.
Empty any decorative outer pot after watering so roots aren't left submerged.
Water carefully
Citrus needs moisture but dislikes waterlogged roots. Check compost below the surface and water when needed, allowing drainage.
The correct frequency changes with season, light and pot size. A seedling in summer may dry much faster than the same plant in a cool winter room.
Yellowing foliage has several possible causes, including excess water, dry roots or inadequate light. Look at conditions before adding more fertiliser.
Feed at the right stage
Established citrus plants can benefit from seasonal citrus feeds according to the product and RHS guidance. Tiny seedlings don't need heavy feeding immediately after germination.
Use a suitable diluted feed only when the plant has developed enough to require it. Overfeeding can damage roots and lead to salt accumulation in pots.
Follow the label rather than applying large amounts to force rapid fruit production.
Protect from British winter conditions
Most lemon plants require protection from frost. Bring them into a bright, appropriately cool or warm sheltered place according to cultivar and growing guidance.
Avoid putting the pot next to a hot radiator in a very dark room. That combination can encourage leaf drop and stress.
Keep an eye on watering as growth slows. Wet compost stays wet longer in winter.
Encourage healthy branching
As the plant matures, appropriate pruning can help manage height and shape. Wait until it is established before cutting back stems.
Use clean tools and follow citrus pruning guidance. Severe cutting of a small seedling may delay growth.
Remember that a seed-grown citrus plant can eventually become a substantial tree if conditions allow.
Will a seed-grown lemon fruit?
It may, but seedlings can take years to flower, and indoor British conditions may not support reliable ripening. Fruit traits aren't guaranteed to match the original.
Pollination, light, nutrition and season length all affect production. Commercial grafted lemon plants are more predictable for someone who wants to harvest.
A healthy green plant is still a good outcome from a seed that would otherwise have gone in the bin.
Watch for pests
Indoor citrus may attract scale insects, spider mites or other pests, especially under warm dry conditions.
Inspect leaves and stems regularly and follow appropriate horticultural control guidance if needed. Don't spray random household insecticide around edible plants.
Healthy light and careful watering help, but a pest problem needs correct identification.
A simple seed project
Rinse several fresh seeds, sow shallowly in moist free-draining compost, keep warm and bright and be patient.
Pot up healthy seedlings as they grow and protect them from frost. The satisfying part is growing a citrus houseplant from an ordinary kitchen fruit.