Growing Sage from Seed: Germination, Potting up and the First Year

Expect two to three weeks, not four days

Sage germinates at 65 to 70F (18 to 21C) and takes two to three weeks even at that temperature. Half the seed in a packet often comes up a week after the other half. That slow, staggered emergence is normal, so do not resow over the top of a tray that looks empty at day ten. You will end up with two ages of seedling in one pot and lose both.

Below 60F (15C) the seed sits and takes on water without moving, and in a wet, cold seedbed it goes moldy. Warmth from below is worth more than warmth in the air: a propagator, or a tray on something that stays gently warm, cuts the wait to around twelve days. Above 77F (25C) germination drops off again, so a hot windowsill in full summer sun is not the answer either.

Sage seed loses viability fast. A packet three years old will give you a scattered few seedlings at best. If a sowing fails completely, suspect the age of the seed before you blame yourself.

Sow shallow into a gritty mix

The single biggest cause of failure is a rich, water-holding seed-starting mix. Sage seedlings collapse at the base long before they run short of anything. Mix one part sharp grit or perlite into three parts ordinary seed-starting mix so that water runs straight through, and the same watering that would kill a seedling in peat becomes harmless.

1. Cover to about an eighth of an inch Sow on the surface and sift a bare eighth of an inch (3 mm) of compost over the top. Sage needs darkness less than it needs contact with damp soil, but buried half an inch deep it will not reach the light.
2. Two seeds per cell, or thinly in a tray Modules save you the transplant check. Put two seeds in each cell and pull the weaker one at the first true leaves. In an open tray, sow far enough apart that you can lift each seedling without touching its neighbor.
3. Water from below, then leave it Stand the tray in shallow water until the surface darkens, then take it out and let it drain fully. Repeat only when the top of the compost is dry to a fingertip. Daily watering from a can is what kills sage seedlings.
4. Give them full light the day they emerge Sage seedlings stretch badly in poor light and a stretched one never thickens at the base. Move the tray to the brightest place you have as soon as the first pair of seed leaves stands up.

Pot up before the roots start circling

Sage puts down a strong taproot early and resents being left in a small cell once it has filled it. Move each seedling into a three and a half inch (9 cm) pot when it has two or three pairs of true leaves, which is usually four to six weeks from sowing. A plant checked at this stage stays stunted for the rest of the season.

Use a free-draining potting mix, not seed-starting mix, and a terracotta or plastic pot that you can lift to judge weight. Learning to water sage by weight rather than by schedule starts here: a pot that still feels heavy does not need water, whatever the surface looks like.

1. Handle by the leaf, never the stem A crushed seedling stem does not recover. Lift each plant by a seed leaf with a dibber under the roots, and hold it at the same depth it was growing at.
2. Do not plant it deeper Burying the base of the stem to steady a floppy seedling invites stem rot. If it will not stand up, it needs more light, not more compost.
3. Pinch the tip at six inches When the plant reaches about six inches (15 cm), pinch out the growing tip above a pair of leaves. It branches from the joints below and starts building the low, many-stemmed frame that keeps it upright in later years.

Plant out into lean soil after the last frost

Harden off over a week or ten days once frosts have finished, then plant into the sunniest, sharpest-draining spot you have. Sage wants poor ground. Adding compost or manure to the planting hole produces soft, sappy growth that gets through its first winter far less well than a plant grown hard on thin soil.

Space plants 18 to 24 inches (45 to 60 cm) apart. That looks absurd around a four inch seedling, and it is correct: a mature plant is two feet across, and one crowded into a foot of space holds still, damp air in its center all winter and rots off at the base.

On heavy clay, plant on a low mound three or four inches high rather than into a hollow. The crown then sits above standing water in winter, which is where most first-year losses happen.

The first year is for roots, not for cooking

A seed-raised sage is not fully productive until its second summer. Take a few leaves as you need them, but no more than a fifth of the growth in the whole first season. Everything the plant does not lose to your kitchen goes into a woody base and a deep root, and that is what carries it through winter and gives you an armful of leaves the following year.

Stop taking anything at all about eight weeks before your first expected frost. The soft growth that follows a late picking has no time to harden and it is the first tissue to blacken when cold arrives.

1. Write down the sowing date and the emergence date The gap between them tells you next year whether your compost was warm enough. Two weeks means the conditions were right; four means you sowed too early or too cold.
2. Record how many seedlings survived potting up Losses at potting up point to watering; losses in the tray point to compost. Knowing which one you had this year decides what you change next year.
3. Mark where each plant went Sage dies back to bare wood over winter and is easy to dig up by mistake in early spring. Note the position of each plant, and note which ones came through, because the survivors tell you where in the garden sage actually wants to be.