Germination temperature
Best at about 30 °C (86 °F) in laboratory tests; alternating 20-30 °C (68-86 °F) also works well. 40 °C (104 °F) is less favourable.
Tree growing guide
Shisham is a fast-growing, nitrogen-fixing timber tree of the Indian monsoon belt whose seed germinates within days in warm conditions. This guide covers pod versus clean seed, why boiling water is the wrong treatment for this legume, and how to raise strong nursery seedlings.
Best at about 30 °C (86 °F) in laboratory tests; alternating 20-30 °C (68-86 °F) also works well. 40 °C (104 °F) is less favourable.
Shallow: just cover the seed or pod piece with a thin layer of fine soil or sand.
About 3-11 days for clean seed at 25 °C (77 °F); pods with seed still inside are slower.
No special light is needed for germination; seedlings need full sun.
Usually none; nicking or cutting the pod edge can help. Do not use boiling water or acid.
Both work: raise seedlings in a nursery or sow directly at the site.
Shisham seed comes either as clean seed (about 45,000-55,000 per kg) or still enclosed in flat, papery pod pieces, each usually holding one seed. Clean seed germinates faster and more evenly. If you have pod pieces, you can sow them whole or carefully break or cut the pod open to release the small kidney-shaped seed.
Usually not needed: the ICRAF tree guide for Tanzania lists no pre-treatment and about 70% germination. Where seed is slow, a 2020 study found light abrasion with sandpaper and cutting the side of the seed or pod the most effective treatments, while scalding in boiling water, overnight soaking in boiling water and sulphuric acid gave low to zero germination. In a pod trial, cutting both edges of the pod gave better germination than whole pods.
Not needed. Shisham is a tropical and subtropical tree with no cold requirement.
Optional. Soaking cut pods in plain tap water for 24 hours gave the best result in a nursery trial; soaking alone, without cutting the pod, made little difference. Never pour boiling water over shisham seed.
In tests at the Forest Research Institute, Dehradun, 30 °C (86 °F) gave the highest and fastest germination; alternating 20-30, 25-30 and 30-40 °C were also effective, while a constant 40 °C (104 °F) was less favourable. Sow in the warm season, not in a cold spell.
Keep it shallow. Lay seeds or pod pieces flat and cover them with a thin layer of fine soil or sand, just enough to hide them.
A light, well-drained mix such as sandy loam. Shisham grows slowly on poorly aerated, heavy clay, so avoid sticky soil in seed trays and polybags.
Keep the medium evenly moist but not waterlogged until seedlings are established.
Germination does not need light, but move trays into full sun as soon as seedlings appear to avoid weak, stretched growth.
Clean seed at 25 °C (77 °F) germinated in about 2.7-11 days depending on the seed source, and germination was complete within 9 days at 30 °C (86 °F). Seed still inside the pod takes longer.
Prick out seedlings into individual polybags or deep pots once they can be handled, and plant out at the start of the monsoon so the roots establish with the rains. Plantations are spaced from 1.8 x 1.8 m (6 x 6 ft) for straight timber up to 4 x 4 m (13 x 13 ft).
Young trees grow quickly in full sun. Keep weeds down around the seedling, protect it from grazing and watch for termites, which attack young trees.
Cause: shisham seed is not a hard-coated legume like acacia, and boiling water kills it. Fix: sow fresh seed dry or after a plain cold-water soak; nick or cut the pod edge if germination is slow.
Cause: the large cricket Brachytrypes portentosus is a recorded nursery pest of shisham. Fix: check beds at night, keep the nursery clean and raise seedlings in containers off bare soil where crickets are common.
Cause: termites attack young shisham trees. Fix: plant healthy, well-grown seedlings, avoid buried woody debris in the planting pit and use locally recommended termite control.
Cause: the defoliator Plecoptera reflexa and the leaf binder Dichomeris eridans. Fix: inspect young plants regularly and remove affected leaves early; established trees usually recover.
Cause: leaf spot (Cercospora sissoo), leaf blight (Colletotrichum sissoo) and powdery mildew. Fix: give seedlings space and air movement and avoid wetting the foliage in the evening.
Shisham grows from sea level to about 1,500 m (4,900 ft) with 500-4,500 mm of annual rain and tolerates a dry season of up to 6 months, which makes it well suited to much of India.
The seed tolerates drying. Kept dry and cool in an airtight container it stays viable for 1-2 years, and up to about 4 years in hermetic storage. Seed stored well for a year germinated as well as fresh seed in FRI tests.
Besides seedlings and direct sowing, shisham can be grown from cuttings and root suckers, and it tolerates lopping, pollarding and coppicing.
In plantations, the first thinning at canopy closure, around year 6, removes 30-40% of the stems so the best trees can grow on.
Sow shisham seed in the warm season for a fast-growing shade and timber tree.
No. Shisham seed is easily damaged by heat: in a 2020 study scalding and boiling-water soaks gave low to zero germination. Sow fresh seed as it is, or lightly nick it or cut the pod edge and soak in cold water for up to 24 hours.
It helps. Clean seed germinates faster and more evenly; whole pods can still be sown, but cutting the pod edges improved germination in a nursery trial.
In warm conditions, within days: clean seed germinated in about 3-11 days at 25 °C (77 °F), and germination was complete in 9 days at 30 °C (86 °F).