Gadenin日本語Get the appWhy the seed sits there and does nothing
Echinacea seed carries a dormancy mechanism that stops it germinating in the autumn it falls, which on the prairie would send a soft seedling into winter and kill it. The seed only releases that block after it has been through a period of cold while damp. Sow it warm and dry-stored straight into a heated propagator and you will typically get a scattering of seedlings from a whole packet, and gardeners reasonably conclude the seed was bad.
Give the same packet four to six weeks of cold and moisture first and germination jumps sharply, often to well over half the seed. The effect is real and it is the single biggest thing separating a disappointing sowing from a good one. Fresh seed from your own plants responds even better than bought seed.
Two ways to give it the cold period
You can either let the winter do it outdoors, or do it deliberately in the fridge. Outdoors is less work and suits anyone with cold winters; the fridge method gives you control over the timing and works anywhere, including in mild climates where the winter is never cold enough to break dormancy on its own.
- Outdoor method: sow in autumn and leave it out Sow into pots or trays of ordinary seed-starting mix in autumn, cover with a quarter inch (5 mm) of grit, and stand them outside in a sheltered spot or an open cold frame where rain reaches them. Protect from mice, which take the seed. Seedlings appear in spring when the soil warms.
- Fridge method: damp sand or paper for four to six weeks Mix the seed into a handful of just-damp sand or fold it into a barely moist paper towel, seal it in a labeled bag, and keep it in the fridge at around 40F (4C) for four to six weeks. Damp means damp, not wet; free water in the bag causes mold.
- Sow at moderate warmth, not high heat After the cold spell, sow into trays and keep them at 65 to 70F (18 to 21C). Coneflower does not want the high bottom heat that suits tomatoes; above about 75F (24C) germination actually falls off.
- Cover very lightly and keep the surface just moist Cover the seed with about an eighth of an inch (2 to 3 mm) of compost or fine grit. It germinates better with a light covering than sown on the bare surface. Keep the tray evenly moist but never sodden, ideally by watering from below.
- Expect ten to twenty days Germination usually starts around day ten and continues for another two weeks. Do not throw the tray away early; the later seedlings are just as good as the first ones. Move the tray into full light the moment the first shoots break the surface.
If a batch germinates in the fridge before you are ready, do not wait. Sow those seeds immediately, roots downward, and treat them as normal seedlings.
The first eight weeks
Coneflower seedlings are slow and unremarkable for the first month, which catches people out. The two seed leaves are small and rounded, the first true leaves are narrow, and the plant puts most of its early energy into a root rather than into visible top growth. Nothing is wrong; this is a plant that builds downwards first.
Transplant into individual small pots once the first pair of true leaves is fully open, handling the seedling by a leaf and never by the stem. Use a free-draining compost and choose a deep pot rather than a wide one, because the taproot goes down early. Grow them in the best light you have, and keep them a little on the dry side rather than a little wet; damping off is the main cause of losses at this stage.
Feed weakly, if at all, with a half-strength general feed once a month. Overfed seedlings make soft floppy growth that struggles when it goes outside.
| Stage | Timing after sowing | What to do |
|---|---|---|
| Germination | 10 to 20 days | Move to full light immediately, reduce warmth slightly |
| First true leaves | 3 to 4 weeks | Transplant into individual deep pots |
| Four to six leaves | 6 to 8 weeks | Harden off over ten days before it goes outside |
| Planting out | 10 to 12 weeks, after the last frost | Space 18 to 24 inches (45 to 60 cm) apart in full sun |
| First flowers | Usually the second summer | Do not feed to force flowers in year one |
Planting out and surviving the first winter
Harden the plants off properly over about ten days, increasing their time outside gradually, then plant after the last frost into full sun. Set the crown level with the surrounding soil, water them in well, and water deeply once a week through their first summer. Do not add rich compost to the planting hole; if your soil is heavy, work in coarse grit instead.
The first winter is the dangerous one. A young plant has a small crown and a shallow root system, and it is far more likely to rot in cold wet soil than an established clump. Keep mulch away from the crown, make sure nothing drips onto the plant from a roof or a gutter, and if your soil is heavy consider growing the seedlings on in deep pots through their first year and planting them out the following spring instead.
What to record about your seedlings
Write down the sowing date, the length and method of the cold treatment, and how many seedlings you got from how much seed. Germination rates vary enormously between seed sources and between your own batches, and after two seasons your own figures will tell you exactly how long a cold spell your seed actually needs.
Once the seedlings are planted, record the position of each one. They will not flower until their second summer, and when they finally do you will want to know which plant came from which sowing, especially if you saved seed from a plant you liked. Note the date each seedling first flowered as well; a plant that flowers strongly in its second year from seed is one worth taking root cuttings from later.