Gadenin日本語Get the appSow where it is to flower, and nowhere else
Nemophila puts down a fine, brittle taproot within days of germinating and it does not forgive being lifted. Plants transplanted of a tray or shifted from a pot sulk for a fortnight, go yellow at the base, and flower half the size of a direct sown neighbor that went in on the same day. This is not a plant to raise under cover and set out later, and a strip of seedlings that comes up in the wrong place is better pulled and resown than moved. Decide the position before the seed leaves the packet.
The seed is small, dark and roughly the size of a pinhead, which makes it easy to sow far too thickly. Mix it with a pinch of dry sand in the palm if you are scattering it over a wide area, or place it in stations if the patch is small. Broadcasting straight from the packet gives a mat of seedlings so dense that thinning becomes a two hour job on hands and knees, and the ones you leave behind have already been drawn up thin and pale by competition.
- Clear the ground and rake it fine Take out perennial weed roots and rake to a crumb tilth. Nemophila seedlings are small and slow for the first three weeks and cannot outrun weed seedlings that come up alongside them.
- Sow thinly over the whole area Scatter across the patch rather than in a straight line. A drift reads as one sheet of blue, and the plants prop each other up when they flop, which they will.
- Cover the seed lightly An eighth of an inch (3 mm) of fine soil is enough. Nemophila germinates better in darkness, and seed left bare on the surface dries out between waterings or is taken by birds.
- Firm and water once Press the surface down with the back of a rake so the seed is in contact with damp soil, then water with a fine rose. Keep the top inch (2.5 cm) damp until the seedlings are through.
- Thin in two passes At two true leaves take the patch back to one plant every three inches (8 cm), and at four true leaves to one every six to nine inches (15 to 23 cm). Pinch the surplus off at the ground rather than pulling, so the roots of the keepers are not disturbed.
Autumn where winters are mild, very early spring everywhere else
Nemophila is a cool season annual that finishes in heat, so the whole aim of the sowing date is to get the plant to flowering size while the weather is still cold. Where winter lows stay above about 20F (minus 7C), sow in autumn once the summer heat has broken. The seedlings sit as small green rosettes through the winter, root deeply while nothing is being asked of them, and flower six weeks earlier and half again as big as anything sown in spring.
Where winter is genuinely cold, sow as early in spring as the ground can be raked, which is usually several weeks before the last frost date. Young nemophila takes a light frost without damage and germinates in soil far too cold for most annuals. Waiting for warm settled weather is the single commonest mistake with this plant: a late sown patch is only just coming into flower when the first hot spell arrives, and it collapses with most of its buds unopened.
| Sowing time | Suits | What you get |
|---|---|---|
| Autumn, after the heat breaks | Winters above 20F (minus 7C) | Largest plants, earliest and longest flowering |
| Late winter, ground just workable | Mild areas with wet winters | Good display, a couple of weeks behind autumn sown |
| Early spring, before the last frost | Cold winters | The standard sowing, flowers by late spring |
| After the last frost | Nowhere, if it can be helped | Short, thin plants that quit as soon as it turns hot |
Temperature at germination, and how long to wait
Soil between 55 and 65F (13 and 18C) brings nemophila up in seven to fourteen days. Colder ground is slower but perfectly safe, and seed sown into cold soil in late winter simply waits, sometimes for a month, and germinates the week the ground warms. Warm ground is the problem rather than the solution: above about 75F (24C) germination becomes patchy and erratic, and the few seedlings that appear are already fighting conditions that will finish them.
Do not soak, chill or scarify the seed, and do not sow into ground that has just had a heavy dressing of manure. Nemophila germinates and grows perfectly well without any of it, and a rich seedbed produces soft leafy plants that flop earlier and flower less. Fresh seed germinates best, so if you have collected your own, sow it the same season rather than saving it for a second year.
| Soil temperature | Days to emerge | Notes |
|---|---|---|
| 40 to 50F (4 to 10C) | Twenty to thirty days | Reliable but slow, normal for a late winter sowing |
| 55 to 65F (13 to 18C) | Seven to fourteen days | The target range, even emergence |
| 65 to 75F (18 to 24C) | Five to ten days | Fast, but keep the surface damp or losses are heavy |
| Above 75F (24C) | Patchy or none | Too late in the season, wait for autumn |
Nemophila germinates better covered than uncovered. If you have sown into a container, lay a sheet of newspaper over the surface until the first seedlings show, then take it off the same day.
Spacing, and why a drift beats a row
A grown plant is six to twelve inches (15 to 30 cm) tall with stems that sprawl outward to cover a foot (30 cm) or more of ground. Those stems are brittle and hollow, and a plant standing on its own splays open in the first heavy rain, leaving a bare center with the flowers face down in the soil. Grown shoulder to shoulder in a block, the same plants lean on each other and hold the whole sheet of flower up at knee height. This is why nemophila is sown in drifts and almost never in a single line.
Six to nine inches (15 to 23 cm) between plants after thinning is the working figure for a bed. Along a path edge or the front of a border, go to six inches (15 cm) and let it knit into a solid band. In a container or window box, four plants to a twelve inch (30 cm) pot fills it and the stems spill over the rim, which is the one situation where flopping works in your favor.
What to write down at sowing time
Record the date you sowed, the date the first seedlings showed and the soil conditions on the sowing day, because those three together tell you next year whether you were early enough. Mark the corners of the patch as well. Nemophila seedlings are small and easily hoed off by mistake before you recognize them, and an unmarked autumn sowing is regularly destroyed by its own gardener during a tidy up in late winter.
Note the date of the first flower and the date the plants gave out in heat. The gap between them is the length of your display, and if it was short, the fix is almost always to sow earlier rather than to feed or water more. Two seasons of those dates will tell you the exact window that works in your garden, which no general advice can.