Sweet Marjoram Growing Calendar: Sowing, Cutting and Overwintering

The year at a glance

Marjoram gets one growing season in most gardens, and its useful window is narrower than oregano's at both ends. It will not start until the soil is warm and it stops for good at the first hard frost, so the whole year is about not wasting the warm weeks in the middle.

Late winter to spring: start it indoors and keep it lean

Sow eight to ten weeks before your last expected frost. Marjoram is slow at the start, taking eight to fourteen days to germinate at 65 to 70F (18 to 21C) and then several weeks to make anything you would recognize as a plant, so an early start is genuinely useful, unlike with fast herbs.

Once the seedlings are up, move them somewhere bright and cooler. Warmth without strong light is what produces the leggy pale seedlings that never make a decent plant. Pinch the tips at four or five leaf pairs to start building a bushy shape while the plant is still indoors.

1. Surface sow and do not cover The seed needs light to germinate. Press it onto the surface of a fine moist mix and leave it exposed, covering the tray only until germination begins.
2. Drop the temperature after germination Move the tray to around 60F (16C) and the brightest place you have as soon as seedlings appear, and take any cover off.
3. Transplant at two true leaf pairs Move seedlings into individual cells or small pots of gritty mix. They are small and fragile at this stage, so handle them by a leaf, never by the stem.
4. Pot up once, then hold A three inch (8 cm) pot is plenty until planting out. Keeping them slightly restricted stops them getting soft while they wait for the weather.

Late spring: plant out later than feels right

This is the decision most people get wrong. Marjoram planted into cold soil sits still, goes bronze and often rots, while the same plant set out two weeks later into warm soil overtakes it within a month. Wait until nights hold above 50F (10C) and the soil at planting depth is above 54F (12C).

Harden off over a week: outdoors in a sheltered spot during the day, back under cover at night, then two nights out before planting. Space plants eight to twelve inches (20 to 30 cm) apart in full sun, on ground raised slightly if your soil is heavy, and water once at planting. After that let the surface dry between waterings.

If a late cold night is forecast after planting out, cover the plants with an upturned pot or a cloche for the night. One frost on newly planted marjoram will kill it outright.

Summer: pinch, then make the cut that matters

Through early summer the job is simply to keep pinching. Take two inches (5 cm) of tip from all over the plant every week or so; it keeps the plant dense, delays flowering and supplies the kitchen at the same time. Water deeply but only when the top two inches (5 cm) of soil are dry, and always in the morning.

Then watch for the knots. When tight green flower buds appear across most of the shoot tips, you have roughly a week to make the main cut of the year at peak flavor. Cut the plant back by about a third to a half, leaving green leaves below every cut, and dry what you take. The plant regrows within three weeks and usually gives a second flush, and in a long warm season a third.

1. Check the tips twice a week from midsummer The closed-knot window is short. Once you see knots forming on a quarter of the shoots, plan to cut within the week.
2. Cut on a dry morning After two rain-free days, once the dew has lifted. Wet material dries badly and loses most of its scent in the bundle.
3. Feed once after the cut, lightly A single half-strength balanced feed pushes the regrowth. Do not repeat it: soft growth from repeated feeding is bland and rot-prone.
4. Let some flowers open on one plant If you want seed, or bees, leave one plant to flower fully. It will stop producing good leaf, so pick a plant you can spare.

Late summer and autumn: decide, then act early

By late summer you have to decide whether this plant is an annual you will let go or one you will carry through winter. Make the decision while the weather is still warm, because both routes need action before the cold arrives. If you are keeping it, take cuttings in late summer while nights are still warm, or lift the whole plant into a pot several weeks before the first expected frost so it can settle indoors while there is still light.

Either way, stop cutting about six weeks before your first frost date. Soft late growth blackens at the first cold night and, on a plant you intend to bring in, gives you nothing but material for spider mite to work on.

1. Take cuttings in late summer Six tip cuttings from clean non-flowering growth, rooted in a gritty mix. They need six weeks of warmth before the light drops.
2. Lift whole plants before the first frost Dig with a good root ball, pot into a container barely larger than the roots, cut the top back by a third and stand it outside in shade for a week before bringing it in.
3. Inspect anything coming indoors Check leaf undersides for mite and aphid before the plant crosses the threshold. It is far easier to deal with outside.
4. Collect seed if you want it Once the knots brown and dry on a plant left to flower, rub them over a bowl and separate the fine seed from the chaff. Store it dry, cool and dark.

Winter, and the dates worth writing down

Indoors, keep overwintering plants at 50 to 60F (10 to 16C) in the brightest place available and nearly dry, with no feed at all until the days lengthen. The plant is resting, not growing. Water only when the pot is noticeably light, check the leaf undersides weekly for spider mite, and pinch the tips once in late winter as new growth starts.

Four dates make next year easier: the date you sowed, the date you planted out and how the plant behaved for the fortnight afterwards, the date the knots first appeared, and the date of the first frost that damaged it. Together those bracket your actual growing window, which is nearly always narrower at the start and wider at the end than the general advice suggests. Note the position of each plant too, because in a cool summer the difference between a bed against a warm wall and an open bed is a matter of weeks.