Plums from seed are a quiet, patient project: the pits need a cold spell, germination takes 30–90 days, and the tree takes 2–4 years to mature. Like all stone fruit, plums do not come true from seed — but seedling plums are vigorous, often fruit well, and a packet of pits costs nothing.
A grafted nursery tree is the reliable way to get a known plum, but seed is a worthwhile experiment — plums fruit sooner than apples and the seedlings are tough. This guide covers cracking the pit, the stratification, and the fast growth that follows. Plums can be started indoors or direct-sown — its sowing method is listed as "both" — and indoor sowing is the better choice if you want an earlier start, more even germination, or plants ready for the first warm weeks of the season. This crop is in the Rosaceae family, needs full sun, and takes 730–1460 days to reach maturity, so the timing below is built around those facts, not guesswork.
Plums at a glance
| Growing factor | What plums need |
|---|---|
| Days to germination | 30–90 |
| Sowing method | both |
| Days to maturity | 730–1460 |
| Soil pH | 6.0–7.0 |
| Spacing | 144–180 inches |
| Sun | full sun |
| Cold tolerance | hardy |
When to start plums seeds indoors
Start stratification in early winter, then sow indoors 12–16 weeks before your last frost. In Zones 3–5, plant out in late spring after the last frost. In Zones 6–8, plant out in spring or autumn. In Zones 9–10, autumn planting suits young trees. In frost-free Zones 11–13, plums struggle without winter chill. Check your local extension service for frost dates, or use our frost-date calculator and seed-starting calculator.
As a rule, work backwards from your last frost: sow indoors 12–16 weeks before it if you are starting indoors at all, and check the seed packet against the germination time of 30–90 days. Our seed-starting calculator does the backwards maths for you, and the germination-time calculator helps you plan around that 30–90-day window. If you are unsure of your zone, the hardiness-zone finder will confirm it.
What you need
plum pits, a nutcracker, a sealable bag and damp sand or peat for stratification, a seed tray or deep pots, seed-starting mix, a clear lid, a spray bottle, a grow light or bright windowsill, labels, and larger pots for potting on.
You will also want a spray bottle or a watering can with a fine rose, and a notebook to record the sowing date — germination takes 30–90 days, and it is easy to forget when you sowed.
Step by step: starting plums seeds indoors
- Fill your containers. Fill trays or pots with fresh, damp seed-starting mix — not garden soil, which is too heavy and can carry disease. Press it down lightly and level the surface.
- Sow the seed. Plum seed sits inside a hard pit. Crack the pit gently — a nutcracker works well — and take out the kernel, which is the seed. Mix the kernels with damp sand or peat in a sealed bag and refrigerate for 8–12 weeks, then sow shallowly in damp seed-starting mix. Germination takes 30–90 days and is uneven. Keep the mix damp and the tray bright.
- Cover and label. Cover the tray with a clear lid or cling film to hold humidity, and label it with the crop and the date. Put it somewhere warm and bright, out of direct sun until seeds sprout.
- Wait for germination. Germination takes 30–90 days. Check the tray daily, mist the surface if it dries, and be patient — uneven germination is normal, especially for slow crops. Our germination-time calculator helps you track the window.
- Remove the cover. As soon as seedlings emerge, take the lid off. Good airflow from this point on is what prevents damping off.
- Give them light. Move the tray under a grow light or to your brightest window immediately — seedlings stretch within a day or two if the light is weak.
- Thin and pot on. Thin to one seedling per cell once they have two true leaves, snipping the extras rather than pulling them. Pot on into larger pots when roots show at the drainage holes, keeping the seedlings at the same depth.
- Feed lightly. Once seedlings have two sets of true leaves, feed with a half-strength liquid feed every week or two. Do not overfeed — soft, overfed seedlings are more likely to damp off and less likely to harden well.
Light for seedlings
Give plum seedlings 14–16 hours of bright light a day. A grow light a few inches above the leaves keeps them compact. Weak light produces tall, floppy seedlings that are hard to handle.
Watering seedlings
Plums have moderate water needs. Keep the mix evenly moist while seeds germinate, then water from below and let the surface dry slightly between waterings. Young plums dislike both drought and waterlogging. Our watering calculator can help you work out how much water your seedlings need as they grow.
Hardening off
Plums are hardy once established, but seedlings need a gentle introduction: 10 days of increasing outdoor time, starting in sheltered shade and building to full sun. Do not plant out until seedlings are sturdy.
Transplanting outdoors
Grow seedlings on in pots for their first season, then plant out in full sun, in soil pH 6.0–7.0. Space trees 144–180 inches apart — a seedling plum becomes a full-size tree. Our plant-spacing calculator works out the layout. Protect young trees from rabbits and deer, and stake them for the first year. For the full picture — soil, feeding, pests and harvest — see our complete growing plums guide.
Common problems and fixes
| Problem | Fix |
|---|---|
| Seeds never germinate | Plum seed needs the pit cracked and 8–12 weeks of cold stratification, then 30–90 days in damp mix. A whole pit sown without chilling may take a year or never sprout. |
| Leggy seedlings | Not enough light. Move the grow light closer and give 14–16 hours a day. |
| Damping off | Seedlings collapse at the base. The mix was too wet. Water from below and remove the lid once seeds sprout. |
| Japanese beetles after transplanting | Beetles skeletonise the leaves. Pick them off by hand into soapy water in the morning. |
Seeds never germinate
Plum seed needs the pit cracked and 8–12 weeks of cold stratification, then 30–90 days in damp mix. A whole pit sown without chilling may take a year or never sprout.
Leggy seedlings
Not enough light. Move the grow light closer and give 14–16 hours a day.
Damping off
Seedlings collapse at the base. The mix was too wet. Water from below and remove the lid once seeds sprout.
Good companions for plums include borage, marigolds, clover, chives. Watch out for aphids, Japanese beetles, birds, spider mites — check young plants regularly, and deal with pests early while plants are small. Our pest-identifier helper can help you work out what you are looking at.
Frequently asked questions
How long do plum seeds take to germinate?
30–90 days after cracking the pit and 8–12 weeks of cold stratification in the fridge.
Do I need to crack the plum pit?
Yes — the kernel inside is the seed, and it germinates far more reliably once freed from the pit.
Will a seed-grown plum taste like the parent?
Not exactly — plums do not come true from seed. Buy a grafted tree for a guaranteed variety.
How far apart should plum trees be?
144–180 inches apart in full sun, in soil pH 6.0–7.0.
When will a seed-grown plum tree fruit?
Plums take 730–1460 days to mature, so expect fruit in 2–4 years.