Sowing seed
Ten to fifteen years to first flower, and the first two months decide most of it. What to sow into, how field capacity feels, and which alarming things in the box matter.
30-second version first, the whole guide below7 min read
The short version
- Seed is the slowest route to a plant and the only route to a new one.
- Buried seed does not germinate at all.
- The seed needs light, but a sealed clear box in the sun becomes an oven in twenty minutes.
- Steady warmth. 68 to 86°F (20 to 30°C), growers say, constant, through germination and about a month after.
- Nothing rich in the mix: no worm castings, compost or feed.
- Check every day or two through the plastic.
- Emergence usually starts between day 4 and 14, growers report; most of the tray is up inside a month, stragglers after.
Your setup
Pick yours to see what changes in this guide.
Where it grows
In the ground
Nothing in this guide changes in the ground.
In a pot
Nothing in this guide changes in a pot.
Where it lives
Outdoors
Nothing in this guide changes outdoors.
Indoors
A mat should lift soil temperature no more than about 10°F (about 6°C), growers say, run on a soil-probe thermostat.
Foam board underneath sends heat up.
The season
Winter
Cold nights redden them too, growers say, so check the thermometer before you touch the light.
Not winter
Without a mat, sow in late spring or summer, because cold soil refuses.
Lines are from this guide, or from the cultivar library where one says so. For where they come from, see the end of the guide.
Introduction
Seed is the slowest route to a plant and the only route to a new one. A seedling is, growers say, roughly ten to fifteen years to first flower; year-old seedlings buy back about one. What you get for the wait is genetics that never existed before, which is the one thing a cannot do.
It is also, growers say, the only propagation job here that needs near-daily checking for the first three months.
Buy seed properly: most failures start here
Old seed is, growers say, the commonest cause of a tray that never comes up, and the word fresh on a packet proves nothing. Buy from the actual producer and ask what year it came off the plant.
- Open-pollinated seed is fine unless you care who the father was. Then it is useless. In a garden of many strains, insects bring whatever happened to be flowering, growers say.
- Mixed seed is real. If one packet grows that look nothing alike, growers say, seed from several fruits was combined.
- Sticky seed was never washed. Wash it before it goes near a warm sealed box.
- The name on the packet is a hope. Misidentification happens at every scale, growers report — one grower saw seed sold as grow out as . You will not know for years; identification takes that long.
- Wild-collected habitat seed reportedly dodges the open-pollination worry: no other strain for miles, so it is often effectively pure.
The three conditions
- Light on the seed. Surface-sow, never bury. Buried seed does not germinate at all.
- Steady warmth. 68 to 86°F (20 to 30°C), growers say, constant, through and about a month after.
- Moisture at . Damp throughout, nothing pooling or dripping. A hard-squeezed fistful should give a bead or two of water, not a trickle, growers say.
On the surface
light reaches it · it germinates
Buried
no light · no germination
What to sow into
Two substrates both work. Pick one and run it exactly as written before you start improvising. Stitching two methods together is, growers say, why beginners get unrepeatable results.
Straight vermiculite
Sterile out of the bag, inorganic, pH neutral, and it holds water well. Algae and gnat larvae can still turn up in any mix that stays constantly wet, growers report. An inch and a half, leveled, not pressed down. Top with a screened extra-fine layer, growers advise, an eighth of an inch at most, so seed lands on a cushion instead of dropping into lightless gaps.
Sieved soil and pumice
Potting soil through a quarter-inch sieve (bark and sticks are wet sponges and a fungal risk), then half and half with 1 to 4 mm pumice, washed of dust, growers advise. Perlite works but eventually floats to the top and separates. Never sand: it packs down and stunts them.
Straight vermiculite
Sterile out of the bag, inorganic, pH neutral, and it holds water well. Algae and gnat larvae can still turn up in any mix that stays constantly wet, growers report. An inch and a half, leveled, not pressed down. Top with a screened extra-fine layer, growers advise, an eighth of an inch at most, so seed lands on a cushion instead of dropping into lightless gaps.
Sieved soil and pumice
Potting soil through a quarter-inch sieve (bark and sticks are wet sponges and a fungal risk), then half and half with 1 to 4 mm pumice, washed of dust, growers advise. Perlite works but eventually floats to the top and separates. Never sand: it packs down and stunts them.
- The container: growers say anything clear, four inches or taller, that can take drainage holes later. A takeaway box or lidded clear cup is fine.
- Seal with cling film, not the lid. Lids are not airtight. They lose moisture slowly and let things in.
- Nothing rich in the mix: no worm castings, compost or feed. One grower reports a castings-enriched mix that grew white surface mold that came back after every peroxide treatment.
- Sanitize if you like; never sterilize. Growers say sanitizing is four minutes in the microwave, with the moist mix in a covered container whose lid sits loose so steam can escape, then an hour covered to cool; the container and the steam are hot. Sterilizing needs 356°F (180°C) for half an hour, growers say, drives off ammonia and changes the soil chemistry. Skip it.
Sealed, and left alone
condensation on the walls
About two months — it comes off
three rows of spines · holes punched
Sowing
Step 1: Soak the seed (optional, and worth it)
An hour in neat 3% hydrogen peroxide, or 1:1 with purified water for six hours, or as weak as 1:10 for twelve, growers say.
Step 2: Moisten the mix before it goes in
Spray to field capacity, work it through, tip out the excess. If you are filling several containers, growers advise mixing one batch for all of them, so the moisture is the same in every tray.
Step 3: Scatter, do not place
Roll seed off a folded paper crease, brush it off a damp fingertip, or sprinkle like salt, growers say. Placing one at a time is only worth the hour for something rare.
Step 4: Space them about three eighths of an inch apart
Roughly four to six seeds per square inch. Closer and they crowd each other within weeks; much further apart and the tray holds fewer plants for the same care, growers say.
Step 5: Press, mist, seal
Press lightly so they sit on the surface. Mist with a genuine fine mist, growers advise — a stream buries and scatters them. No standing water underneath; if there is, prick a pinhole and drain it.
Step 6: Get the heat right
A mat should lift soil temperature no more than about 10°F (about 6°C), growers say, run on a soil-probe thermostat. The probe goes in an identical dummy container sealed the same way, growers say; in the live tray it shifts about and uproots seedlings. Foam board underneath sends heat up. Without a mat, sow in late spring or summer, because cold soil refuses.
Two months of not opening it
Check every day or two through the plastic. Walls should always show condensation, growers say; if it vanishes, open, mist, reseal. Emergence usually starts between day 4 and 14, growers report; most of the tray is up inside a month, stragglers after.
Normal — leave it alone
Fine white hairs on the first root, at about a week, are root hairs, not mold, growers say. A casing still riding a seedling's head stays put, growers say; it is not worth breaking the seal for. Sideways or upside-down seedlings right themselves as their roots take hold, growers report.
Act today
Orange or red growth on the surface: open up and mist with 3% hydrogen peroxide several times a day until it dies back, growers say. A green algal film usually means an unsanitized organic mix in a warm bright box, growers say. That is often saveable, but give the next tray a cleaner substrate.
Normal — leave it alone
Fine white hairs on the first root, at about a week, are root hairs, not mold, growers say. A casing still riding a seedling's head stays put, growers say; it is not worth breaking the seal for. Sideways or upside-down seedlings right themselves as their roots take hold, growers report.
Act today
Orange or red growth on the surface: open up and mist with 3% hydrogen peroxide several times a day until it dies back, growers say. A green algal film usually means an unsanitized organic mix in a warm bright box, growers say. That is often saveable, but give the next tray a cleaner substrate.
What you are looking at
Step 1: The seed casing, still on
A tiny green sphere wearing its own shell like a hat.
Step 2: Two horns
The , the only two leaves this plant will ever have. Two is normal; three happens and means nothing.
Step 3: The first spines
Now a very small ribbed column. It starts looking like a cactus rather than a bean.
Day zero — on the surface
hard · black · about a millimeter
About a week — the first root
fine root hairs · on one root
The casing, still on
two horns wearing a hat
Blue is not a seedling trait. It arrives after some years. Seedlings from a famously blue plant look plain green for a long time, growers say, and nothing is wrong. Species that are spineless as adults reportedly still carry spines as seedlings and lose them with age.
Common mistakes, try it, quick check and sources
Quick check
Question 1: How deep do the seeds go?
Question 2: It is week one and there is white fuzz around some of the seeds. What do you do first?
Question 3: Your seedlings have gone pink at the tips. What is the likeliest cause?
