Gadenin日本語Get the appSow on the surface: the seed needs light
Marjoram seed is extremely small, a few thousand to the gram, and it germinates on light. Buried under even a shallow covering of compost, most of it will not come up at all, and the usual conclusion that the seed was old is wrong. Press it onto the surface of a moist fine-textured mix and leave it visible.
Sow eight to ten weeks before your last expected frost. Germination takes eight to fourteen days at 65 to 70F (18 to 21C) and is erratic below 60F (16C), so bottom heat or a warm room genuinely helps at this stage even though the seedlings want it cooler afterwards.
- Fill and firm a fine mix Use a seed-starting mix sieved fine, or a peat-free mix with added perlite. Firm it gently and water it before sowing, so you never have to water onto the seed from above.
- Mix the seed with dry sand A pinch of seed stirred into a tablespoon of dry sand lets you scatter it evenly and thinly. Sowing this seed straight from the packet always produces a dense clump.
- Press, do not cover Tamp the seed onto the surface with a flat piece of card so it makes contact with the moist mix. Leave it uncovered and exposed to light.
- Cover the tray, not the seed A propagator lid or a sheet of clear film over the whole tray keeps the surface from drying. Take it off completely the moment the first seedlings show.
- Water from below only Stand the tray in shallow water until the surface darkens, then lift it out. Overhead watering washes surface-sown seed into the corners of the tray.
Marjoram seed stays viable for about three years if kept cool, dry and dark. Older seed germinates thinly and slowly, so sow it more heavily rather than assuming it has failed.
The first month is slow, and that is normal
The seedlings emerge as two round seed leaves barely larger than a pinhead and then appear to do nothing for two or three weeks. This is normal and not a sign of a problem. Marjoram puts down roots before it puts up leaves, and the growth above ground only becomes obvious once the first true leaves, small and gray-green and slightly downy, are established.
Knowing the normal pace matters, because impatience at this stage causes most of the losses. Extra warmth, extra water and early feeding all produce weak drawn seedlings that collapse.
| Stage | Time from sowing | What you should see |
|---|---|---|
| Germination | Eight to fourteen days | Pinhead seed leaves, uneven across the tray |
| First true leaves | Three to four weeks | One pair of tiny gray-green downy leaves |
| Ready to transplant | Five to six weeks | Two true leaf pairs, roots holding the mix together |
| First pinch | Eight to nine weeks | Four or five leaf pairs, plant an inch or two tall |
| Ready to plant out | Ten to twelve weeks | Bushy, three inches (8 cm) tall, roots filling a small pot |
Cooler and brighter as soon as they are up
The warmth that got the seed to germinate is the wrong environment for the seedlings. Once they are up, move the tray to the brightest place you have and drop the temperature to around 60F (16C). Warm dim conditions produce long pale stems that never firm up and are the classic cause of a whole tray failing.
Air movement matters as much as light. Marjoram seedlings are thin-stemmed and prone to damping off, and still humid air around crowded seedlings is what triggers it. A window cracked open on mild days, or a small fan on low across the room, changes the outcome completely.
- Uncover completely at germination Any lid or film comes off the day the first seedlings appear, not a week later. Continued humidity past that point is the main cause of collapse.
- Let the surface dry between waterings Water from below, and only when the surface has gone pale. A permanently wet surface is what damping off needs.
- Turn the tray daily Seedlings on a windowsill lean hard towards the glass. A quarter turn each day keeps the stems straight.
- Remove casualties at once Pull any collapsed seedling and the compost immediately around it as soon as you see it, before it spreads down the row.
Do not feed seedlings before they have two true leaf pairs. There is enough in a seed-starting mix to get them that far, and early feed produces exactly the soft growth that fails.
Transplant into a gritty mix and start being firm with them
Transplant at two true leaf pairs, when the roots are just holding the mix together. Handle each seedling by a seed leaf and never by the stem: a marjoram stem at this stage is a thread, and a pinched stem is a dead seedling.
Move them into a mix with more grit than you used for sowing, roughly one part perlite or sharp sand to three of compost. This is the point at which you start treating marjoram as the dry-hillside plant it is, letting the pots dry noticeably between waterings and keeping them cool and bright rather than warm.
- Lift with a dibber, not your fingers Ease each seedling out from underneath with the point of a pencil or dibber, keeping as much root as possible.
- Plant at the same depth Set the seedling with the seed leaves just above the surface. Buried stems rot; too shallow and it topples.
- One seedling per cell Resist potting two or three together for a fuller look. They compete, stay thin and neither develops a proper root system.
- Water once, then wait Settle them in with one watering and then let the mix dry appreciably before the next. Constant moisture now sets up the rot problems you will meet later.
- Pinch at four or five leaf pairs Take out the top pair with your fingernails. Two shoots break below, and the plant that goes into the ground is bushy rather than single-stemmed.
Harden off properly, and plant out into warm soil
Marjoram raised indoors has soft thin-cuticled leaves that scorch in a day of direct sun and wind. Harden off over a full week rather than the usual two or three days: an hour or two outdoors in shelter and shade on the first day, building to a full day in sun by the end of the week, then two nights out before planting.
Plant out only once nights hold above 50F (10C). Space them eight to twelve inches (20 to 30 cm) apart in full sun on free-draining ground, slightly raised if your soil is heavy, and water once. The plants close the gaps by midsummer, and closer spacing than that traps damp air among the stems and invites mildew.
Record which seedlings you kept
Marjoram from seed varies less than oregano does, but it varies. Rub a leaf of each seedling before you plant it out and note which ones are noticeably sweeter or more strongly scented, and where you put them. Those are the plants to take late-summer cuttings from, and that is how you end up with a marjoram that is better than the packet average.
Also record the sowing date, the germination date and the date you planted out. Marjoram sown too early spends weeks in a pot getting soft and does not catch up; sown at the right moment for your own last frost, it goes into warm soil and grows away without a check. Two seasons of these three dates give you a sowing date you can trust.