Gadenin日本語Get the appDecide first which of the two forms you have
Coix lacryma-jobi is grown in two quite different forms, and almost every disappointment with this crop traces back to sowing one and expecting the other. The bead form carries a shell that hardens into something closer to stone than to grain: glossy, gray to porcelain white to near black, so hard that a hammer is a more realistic tool than a mill. It is grown for stringing, not for eating. The soft-shelled form carries a thin, dull, straw-brown husk that yields to a thumbnail when ripe, and inside it is a white kernel you can actually cook.
You cannot reliably tell them apart from the packet, and seedlings are identical. What you can do is test the seed itself before you sow it. Press a fingernail hard into the shell of a dry seed. If it dents, scores or splits, you have the soft-shelled grain form. If your nail slides off a surface like a glass bead, you have the ornamental bead form, and no amount of good growing will make it edible. A second test: drop one on a hard floor. The bead form rings and bounces; the grain form lands dead.
Both are sown identically, so if you are unsure, sow a short trial row of each source you have and label the rows. One season of side-by-side growing settles the question permanently, because the difference is obvious the moment the beads harden on the stem.
| Test | Hard bead form | Soft-shelled grain form |
|---|---|---|
| Fingernail pressed into shell | No mark at all | Dents, scores or splits |
| Dropped on a hard floor | Rings and bounces | Dull thud, no bounce |
| Surface | Glossy, enamel-like | Matte, faintly ribbed |
| Color when ripe | Gray, white, blue-black, often mottled | Even straw to light brown |
| What it is for | Stringing and craft work | Hulling and cooking |
Sow into genuinely warm soil, and give it the whole season
This is a long-season tropical grass. From sowing to the first hard beads is roughly 120 to 150 days, and the last beads on a plant may take another month after that. There is no fast version of it, so the sowing date is not something to negotiate with: sow too early into cold ground and the seed sits and rots, sow too late and the season ends with the beads still soft and milky.
Wait until all frost risk has passed and the soil at two inches (5 cm) has held 65F (18C) for three mornings running. At 65F (18C) germination takes ten to twenty days, which feels alarmingly slow if you are used to sweet corn. At 75F (24C) it comes down to seven to twelve days. Below 60F (16C) you will lose most of the seed. Where the frost-free season is under about five months, start seed indoors four weeks before the last frost in three-inch (8 cm) pots and set the plants out once nights stay above 55F (13C); Job's Tears transplants well as long as the root ball is not broken up.
Soaking helps, especially with the hard bead form. Twenty-four hours in room-temperature water, changed once, softens the shell enough to shave several days off emergence. Discard any seed that is still floating at the end of the soak; those are empty.
- Soak the seed Cover the seed with room-temperature water for 24 hours, changing the water once at the halfway point. Skim off and discard floaters, which are hollow and will not germinate.
- Sow one to one and a half inches deep Push each seed one to one and a half inches (2.5 to 4 cm) into loose soil and firm it. Shallower than an inch and the tall stems later rock loose; deeper than two inches (5 cm) and emergence becomes patchy in cool ground.
- Space for the size it actually reaches Set seed twelve inches (30 cm) apart in rows twenty-four to thirty inches (60 to 75 cm) apart. Mature clumps stand four to six feet (1.2 to 1.8 m) tall and fan out; closer than a foot and the lower leaf axils, where much of the crop sits, are shaded into nothing.
- Water in and keep it damp until emergence Soak the row at sowing and do not let the top two inches (5 cm) dry out for the two to three weeks it may take to come up. A dry crust during that window is the commonest cause of a thin stand.
Ground that stays wet suits it better than ground that drains
Job's Tears is a wetland grass by origin. It is one of the few grain crops that will grow happily in the low, heavy corner of the garden where everything else sulks, including ground that puddles after rain. Pick the site accordingly: full sun, and the dampest soil you have. It tolerates ordinary garden soil, but on light sandy ground you will be watering constantly all summer and the beads will be fewer and smaller.
Work in a bucket of compost per square yard (square meter) before sowing but do not load the bed with nitrogen. Rich, nitrogen-heavy ground produces six feet of leaf, late flowering and stems that go flat in the first storm. Moderate fertility with plenty of moisture is the combination that fills beads.
Write down what you sowed and where
Because the two forms look identical until autumn, the sowing record is worth more here than in almost any other crop. Note the source of each batch of seed, the row or the end of the row it went into, the sowing date, and the soil temperature you measured. Add the date the first seedling showed. Next season those four lines tell you which seed source gave you edible grain, which gave you beads, and how many days of ground warmth you actually needed to get a good stand.
Also mark the position of the planting itself on a sketch of the beds. Job's Tears self-seeds freely, and the following spring you will want to know whether a seedling coming up in that spot is a volunteer from last year or something you planted deliberately.