🌿 Orchid

Most cultivated orchids are epiphytes and should not be grown in ordinary potting soil. Use a very open, free-draining orchid substrate (usually fir or pine bark), often amended with materials such as sphagnum moss (to retain moisture), perlite or pumice (for aeration), charcoal (to soften the mix) or coconut bark or shavings. Choose the size of the particles according to the thickness of the orchid's roots and your conditions (finer for thin roots/drier homes, coarser for thicker roots/more frequent watering); the aim is to obtain a root zone that remains aerated, drains quickly, while retaining some moisture between waterings. Ensure excellent drainage (pots with plenty of holes; avoid compact, waterlogged environments). Terrestrial orchids (if present) prefer a humus-rich, moisture-retaining but well-drained mix of potting soil and leaf compost, rather than bark alone. Refresh/repair when the medium decomposes and becomes fine/compact (generally every 1 to 3 years, depending on materials and conditions).

Orchids are rarely grown from seed by private individuals. Orchid seeds are extremely fine (dust-like) and have no endosperm; in nature, they germinate only when infected by compatible mycorrhizal fungi. In cultivation, reliable germination is generally achieved by culturing asymbiotic tissue ("flaking") under sterile conditions on a nutritious agar medium. Unless you have sterile culture facilities and experience, start with a nursery plant and concentrate on correct potting. Seed sowing (specialized/vial method): - Requirements: a sterile workspace (e.g. laminar flow hood or well-practiced open-air technique), sterilizers, sterile containers (flasks/jars), sterile tools and a formulated orchid seed germination medium. - Seed sterilization: seeds are surface sterilized before sowing to reduce contamination. - Sowing: distribute seeds on sterile agar medium; seal containers to maintain sterility. - Aftercare: maintain warm temperatures and adequate light; monitor for contamination. Seedlings develop as protocorms, then seedlings. - Deflastification: when seedlings have several leaves and roots, they are gradually acclimatized ("deflasked") to high humidity, then potted into a fine, aerated orchid medium. Planting/potting (most common approach): - Container: use a pot with excellent drainage; choose a pot barely larger than the root mass (transparent pots are often used for epiphytic orchids like Phalaenopsis to keep an eye on the roots). - Medium: use a coarse, aerated orchid mix suitable for the type (usually fir bark with perlite/charcoal; sphagnum moss is sometimes used where greater moisture retention is required). Do not use ordinary garden soil. - Positioning: keep the crown (where the leaves emerge) above the substrate; do not bury the crown. Place the roots gently and backfill without compacting. - After repotting: water to settle the medium, then leave to drain completely. Keep the plant in a well-lit spot, under indirect light and in warm conditions; avoid water stagnation in the crown. - When to repot: generally every 1-2 years, or when the medium decomposes, drainage decreases or the roots protrude from the pot; repotting is most effective when there is new root growth. Propagation (practical alternatives to seeds): - Sympodial orchids: divide mature clumps, ensuring that each division contains several healthy pseudobulbs/canes and roots. - Some orchids produce keikis/plantlets: collect these and pot them once they have several roots long enough to establish themselves in an aerated environment.

Fertilize orchids only during active growth (new roots/leaves and, for many types, during tip/butt development). Use a low-dose water-soluble orchid fertilizer (about 1/4-1/2 of the label dose). A common approach is to "lightly fertilize every week" (a small amount at most waterings), or to fertilize every two weeks if you water less often. Fertilizer type: a balanced formula (e.g. 20-20-20 or similar) is suitable for general use; some growers switch to a slightly higher phosphorus "bloom" formula as the tips develop, but overall, adequate light and correct cultivation are more important than high P content. Urea-free formulas are often recommended for orchids grown in bark or inert media. Application: apply to an already moistened substrate or roots (do not fertilize a dry plant) and ensure good drainage; never leave the pot standing in the fertilizer solution. Salt management: to avoid salt build-up in the fertilizer, rinse the pot thoroughly with clean water regularly (e.g. every 3-4 waterings or about once a month) and discard any run-off water. Seasonal adjustment: reduce or interrupt fertilization when growth slows down (often in winter or when light levels are low) and resume when new growth starts. Note on water quality: if you use rainwater, distilled or reverse osmosis water, add a fertilizer that provides calcium and magnesium (or add a cal-mag supplement) to avoid deficiencies. Avoid over-fertilization, which can burn roots and reduce flowering; don't fertilize stressed, recently repotted or severely dehydrated orchids until they resume active growth.

Only plant a stake when the plant or inflorescence is unstable or in danger of toppling over. For common potted epiphytic orchids (e.g. Phalaenopsis), insert a thin bamboo or metal stake into the growing medium near the edge of the pot, away from the crown; avoid forcing it through the roots or compacting the growing medium. Secure the flowering stem with orchid clips or soft, flexible ties (raffia, Velcro, coated soft wire), placing the first tie at the bottom of the stem and adding additional clips/ties as it lengthens; keep the ties loose enough to allow thickening and slight movement (no shrinkage). For sympodial orchids (e.g. Cattleya type), use a rhizome stake (or 1-2 stakes) to stabilize the newest pseudobulb and prevent the rhizome from swaying; tie the plant gently at the base and again higher if necessary, and use a heavier pot or top dressing (stones) if the plant is top-heavy. For climbing orchids (e.g. Vanilla), provide a moss post, plate or trellis and loosely tie the stems at regular intervals, to allow attachment and growth of aerial roots. Check ties regularly and loosen them before they bite; remove or reduce staking after flowering or once the plant is stable.

Orchids generally require minimal pruning; the aim is to remove spent flower stems and dead or diseased tissue, while preserving storage organs (pseudobulbs/canes) and active roots. - Hygiene: Use sharp tools and sterilize blades between plants and between cuts (e.g. with 70% isopropyl alcohol or a fresh 10% bleach solution) to limit the spread of orchid viruses and bacterial or fungal rots. Discard removed diseased tissue. - After flowering (flowering stems) : - Phalaenopsis (moth orchids; monopod): At the end of flowering, either (a) cut off the green spike just above a node (often the 2nd-3rd node from the base) to try to obtain a lateral spike/new flowering, or (b) cut off the spike at the base if it becomes brown/dry or if the plant is weak and needs to rest. If the stem is entirely brown, cut it off at the base. - Sympodial orchids (e.g. Cattleya, Oncidium alliance, many Dendrobium): Remove the inflorescence or spent flower spike at its base after the flowers have faded. Don't cut off healthy pseudobulbs or stems; they store reserves and can contribute to future flowering. (Some types of Dendrobium can re-flower from older canes; keep the canes green and firm). - Leaves: Only remove leaves that are completely yellow/brown and can be easily detached. Do not prune green leaves or cut the crown of monopodial orchids (risk of crown rot). - Roots (generally when repotting): Only cut dead or rotten roots (brown/black, hollow, pasty or with vellumene). Keep roots firm (often green when wet, silvery when dry). Avoid heavy pruning of roots. Aerial roots should generally be left in place, unless they are obviously dead. - Old sheaths/canes: Remove only dry, loose, papery sheaths if they come off easily; do not remove tight sheaths protecting new shoots. - Wound care: Allow cuts to dry; a light dusting of horticultural sulfur can reduce the risk of infection. Use cinnamon with care (it dries out and is best reserved for small cuts, not live roots). - Timing: Prune just after flowering and/or at repotting time, when new roots are starting to grow; avoid major work when the plant is stressed (heat, drought, active epidemic).