How to Sow Chamomile: Surface Sowing Because the Seed Needs Light

Do not cover the seed at all

Chamomile seed is light dependent. Buried under even a quarter of an inch (5 mm) of soil it sits there, takes up water and rots without ever sprouting. Scatter it on a firmed, level surface and press it down with the flat of your hand or a small board so each seed is in contact with damp soil, and leave it exposed.

The seed is close to dust. A gram holds several thousand of them, so sowing straight from the packet gives you a solid mat in one spot and bare ground everywhere else. Tip it into a cup of dry sand at roughly one part seed to twenty parts sand, shake it, and scatter the mixture. The sand also shows you where you have already been, which is impossible to see with the bare seed.

This applies to both kinds. The annual German type, which is what you grow for tea, and the low creeping Roman type, which is what you grow as a lawn or between paving, are different plants but their seed behaves the same way: surface sown, firmed, never buried.

1. Level and firm the bed first Rake the surface fine and firm it before you sow, not after. Seed that falls into hollows in a rough seedbed ends up buried by the first watering and never comes up, which is why a sowing often germinates in stripes.
2. Mix the seed with dry sand One part seed to twenty parts fine dry sand, shaken in a cup. It spreads the seed evenly and lets you see the coverage on the soil. Damp sand clumps and defeats the whole point, so use it dry.
3. Press, do not rake After scattering, press the surface with a board or your palm. Raking it in buries the seed. Pressing gives you contact without cover, which is exactly what the seed wants.

If you have already sown and covered a bed and nothing has appeared in three weeks, do not dig it over hoping to find seedlings. Firm the surface, sow again on top, and treat the first sowing as lost.

Soil temperature and how long it takes

Chamomile germinates in cool conditions. It moves at soil temperatures from about 50 to 68F (10 to 20C), with 60F (15C) close to ideal. Above about 77F (25C) germination drops off sharply, so a mid summer sowing in a hot climate is the one time you struggle. That makes early spring, as soon as the soil is workable, and early autumn, once the worst heat has broken, the two reliable windows.

Expect seedlings in seven to fourteen days. They emerge as tiny threads with a pair of seed leaves barely a sixteenth of an inch across, so easy to miss that people rake the bed over before the seedlings are visible. Mark the sown area with canes and leave it alone for three weeks before you decide anything.

Keeping the surface damp without washing the seed away

Surface sown seed lives in the top eighth of an inch of soil, and that layer dries out in a couple of hours of sun and wind. One drying is enough to kill seed that has already started to swell. The whole job between sowing and emergence is keeping that thin layer damp without moving the seed off it.

Water with a fine mist, or from below if you are sowing into trays. A watering can rose, even a fine one, floats the seed into the corners and you get a dense clump in one place. Once the seedlings have their first true leaves the roots are deep enough that ordinary watering is safe.

1. Cover with row cover, not soil A sheet of row cover or a piece of shade netting laid on the bed holds moisture at the surface and still lets light through. Take it off the day you see the first seedlings, or they stretch.
2. Mist twice a day in dry weather Morning and late afternoon, enough to darken the surface and no more. Puddles mean you are moving seed around. In cool damp weather you may not need to water at all.
3. Sow in trays if your soil crusts Heavy soil that forms a crust as it dries traps the fine seedlings underneath. Sow into a tray of fine sieved compost, surface sown the same way, and transplant at four true leaves.

Thinning and final spacing

Almost everybody sows chamomile far too thickly, because the seed is invisible and it feels as if you have sown nothing. The result is a mat of seedlings that all stay four inches (10 cm) tall, flower thinly and then collapse into a mildewed heap. Thinning is not optional with this plant.

Thin the German annual type in two stages: to about two inches (5 cm) apart once the seedlings have two true leaves, then to eight to ten inches (20 to 25 cm) apart when they are three inches (8 cm) tall. That final spacing looks absurdly generous on a bed of tiny seedlings, and it is exactly right by flowering, when each plant is a two foot (60 cm) tall bush covered in buds.

The creeping Roman type is thinned differently because you want it to knit together into a mat. Space it four to six inches (10 to 15 cm) apart and let the plants run together over the first season.

Thinnings transplant badly at any size above about two true leaves, because the root is a single fine taproot. Pull them out and compost them rather than trying to move them.

Soil, and why you should not feed it

Chamomile flowers best on thin, free draining soil in full sun. Rich ground and nitrogen feed give you a tall soft plant with big leaves, few flowers and stems that fall over in the first heavy rain. If you are sowing into a bed that had a well manured crop last season, sow chamomile without adding anything at all.

What it will not tolerate is standing water. On heavy clay, raise the bed by four inches (10 cm) or work in coarse grit before sowing. In containers use a free draining mix rather than a moisture retentive one.

Write down the sowing date, the location of the row and the date you saw the first seedling. Chamomile germination is slow enough that without a note you cannot tell, three weeks later, whether the sowing failed or you are simply being impatient. That record makes next year's decision easy.