Germination temperature
Cool: stones often sprout during chilling at 2-3 °C (36-37 °F).
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Plum stones need a long, moist chill before they sprout, and the seedlings may not match the parent fruit. Raise them as rootstocks, hedging or experimental trees, and expect several years before the first crop.
Cool: stones often sprout during chilling at 2-3 °C (36-37 °F).
2.5-5 cm (1-2 in).
After 3-5 months of moist chilling; sprouting is uneven.
Not needed to germinate; full sun for trees.
Cold stratification, ideally after 2 weeks warm and moist.
Sow in pots or a nursery bed; plant out after 1-2 years.
Take stones from fully ripe fruit, scrub off all the flesh and rinse. Do not let the fruit ferment or heat up in a pile: warm fermentation can sharply reduce germination. Stones you will sow within a few weeks only need surface drying; for longer storage keep them dry and cool, ideally at 1-5 °C (34-41 °F).
Not essential. The hard stone (endocarp) lets water in, so plum is not truly hard-seeded, but it slows germination. Carefully cracking the stone or removing the kernel after chilling helps; a high share of stones cracked open but not yet sprouting is the best moment to sow.
Required. Keep the stones moist in damp sand or peat at 20 °C (68 °F) for about 2 weeks, then in the fridge at 2-5 °C (36-41 °F) for 3-5 months. In USDA trials garden plum gave 91% germination after 90 days at 2 °C. Check monthly and sow any stones that crack or sprout.
Not needed beyond the moist stratification. If the stones have dried, soak them in water for a day before you start the warm phase.
Chilled stones germinate at low temperatures; many begin to sprout in the fridge at 2-3 °C (36-37 °F). Sow sprouting stones at once into pots kept cool and bright, or sow outdoors in late winter or spring.
2.5-5 cm (1-2 in). Nurseries sow garden plum about 5 cm (2 in) deep; in pots 2.5-3 cm (about 1 in) is enough.
Deep pots of free-draining, loam-based compost, or a fine, weed-free nursery bed. Stones sown direct in autumn (the traditional nursery method without a fridge) chill naturally over winter where winters are cold.
Keep evenly moist but never waterlogged; stones rot in cold, saturated compost.
Not needed until the shoot appears; then give full light so seedlings do not stretch.
Expect the first sprouts after about 3 months of chilling and stragglers for weeks after. Keep unsprouted stones moist and cool for a second season before discarding them.
Move seedlings into deeper pots once they have a few true leaves, keeping the root ball intact. Grow them on for one to two years in a nursery bed or large container.
Plant while dormant, from late autumn to early spring in temperate climates and in winter in the Indian hills. Choose full sun, shelter from strong wind and no frost pocket; FAO gives about 6 m (20 ft) between orchard trees.
Keep weeds away and water in dry spells while the young tree establishes. If you want a named variety, bud or graft it onto your seedling; in Indian hill nurseries plum is shield-budded in July-August.
Cause: too short or too warm a chill, or stones dried out. Fix: give 2 weeks warm and at least 3 months at 2-5 °C in a moist medium, and keep them moist throughout.
Cause: cold, waterlogged compost or flesh left on the stone. Fix: clean the stones well and use a free-draining mix.
Cause: silver leaf fungus entering pruning cuts. Fix: prune only in dry weather in spring or summer, never in winter or autumn, and cut out infected wood.
Cause: bacterial canker. Fix: avoid autumn and winter pruning and remove affected branches in summer.
Cause: plum moth in Europe; fruit fly in Indian orchards. Fix: clear fallen fruit; FAO lists a bait spray of malathion with sugar for fruit fly where it is permitted.
Seedling plums grow larger than grafted trees and do not come true to type. Use them as vigorous rootstocks or hedging, or graft a named variety onto them.
Plums need winter chilling. European plums do best in the hills; Japanese types such as 'Santa Rosa' suit lower hills, and low-chill cultivars such as Titron, Kala Amritsari and Alubukhara are grown on the north Indian plains.
Fertile, moisture-retentive but well-drained soil, ideally pH 6-6.5, in full sun and sheltered from wind.
Many plums are self-fertile; others need a compatible variety flowering at the same time. Check before relying on a single tree.
Garden plum gives its first seed crop at about 5 years from seed; fruit is ready 95-135 days after full bloom, depending on cultivar.
Chill plum stones through a moist winter and raise sturdy seedlings for rootstocks or your own trees.
Often not. Seedlings may not come true to type and are often more vigorous than grafted trees. To get a known variety, graft or bud it onto the seedling.
Yes, unless you sow them outdoors in autumn where winters are cold. Without about 3 months of moist chilling most stones stay dormant.
Yes, mainly in the hills. On the north Indian plains choose low-chill cultivars such as Titron or Kala Amritsari, because plums need some winter chilling.
Garden plum usually takes about 5 years from seed, longer in poor conditions.