Gadenin日本語Get the appOpen sesame, and why the phrase is a warning
A ripe sesame capsule dehisces. It dries, the seams down its sides give way, the top splits open with an audible crack and the seed inside is flung clear of the plant. That behavior is the origin of the phrase about a door springing open at a word, and for anyone growing the crop it is the whole problem of the harvest in one sentence. Nothing about ripening sesame is gradual once it starts.
The capsules ripen in the same order they were formed, from the bottom of the stem upward, because sesame flowers indeterminately over six to eight weeks. At the moment the lowest capsules are dry and splitting, the ones a foot (30 cm) higher are still green and filling and the tip may still carry flowers. There is no day on which the plant is uniformly ripe, and waiting for one means the bottom third of the crop, the best-filled third, has already been thrown onto the soil.
So you do not wait. The rule is to cut the entire plant when the lowest one or two capsules on the stem have just begun to split, or the day before that, when the lowest capsules have turned from green to a pale brown-yellow and the lower leaves have started to yellow and drop. The capsules further up are mature enough to finish ripening on the cut stem. Cutting a few days early costs you a little seed size. Cutting a few days late costs you the seed itself.
| Sign | What you see | What to do |
|---|---|---|
| Lower leaves yellowing and falling | Bare stem at the base, canopy thinning | Harvest is within one to two weeks. Check every second day |
| Lowest capsules turning brown-yellow | Color change from green, starting at the base | This is the window. Cut now or within two days |
| First capsule split at the tip | A narrow open seam at the top of a low capsule | Cut today. Seed is already being lost |
| Seed on the soil beneath the row | Pale flat seed scattered on bare ground | You are late. Cut immediately and accept the loss |
| Whole stem brown, capsules gaping | Open capsules the length of the stem | Most of the crop has gone. Take what is left gently |
| Frost forecast | Any night near 32F (0C) | Cut everything, ripe or not. Frost kills the plant outright |
Cut in the early morning while there is still dew on the plants. Damp capsules are far less inclined to spring open as you handle them, and a whole row can be carried across the garden with a fraction of the losses you would take working in the dry heat of the afternoon.
Cutting and hanging the whole plant
The harvest is not a matter of picking capsules. You cut the whole plant near the ground, bundle a handful of stems together and hang them upside down so that anything that springs open drops downward into something you have put there to catch it. Every step of the process is arranged around the fact that the seed wants to leave the plant.
Bundles should be small and loose. Six to ten stems tied at the cut ends is right. A thick bundle holds moisture in its center, the capsules there do not dry, and the seed inside molds while the outside of the bundle is finishing perfectly. Hang the bundles head down in a shed, garage, porch or open greenhouse, out of rain and direct sun but with air moving, and put a sheet, tarpaulin or open box directly underneath. A large paper bag pulled up over the heads and tied loosely around the stems does the same job for a small quantity and catches everything, which is the tidiest method for a handful of plants.
Give it one to three weeks. The bundles are ready when the stems snap rather than bend and the capsules have opened along their seams. Shake each bundle over the sheet every day or two rather than waiting until the end, so the capsules that ripened first are emptied before they can spill somewhere you cannot recover them.
- Spread a sheet before you cut anything Lay a tarpaulin or old sheet beside the row. Every plant goes straight onto it and any seed thrown during cutting lands somewhere you can gather it up. This one habit accounts for a large share of what you actually end up with.
- Cut the stems low, one handful at a time Shears or a sharp knife two to four inches (5 to 10 cm) above the ground. Grip the stems first and cut second, then lift steadily without shaking. Keep the heads upright as you move them.
- Tie loose bundles of six to ten stems at the cut ends Bind them with string around the base only. Loose is essential. A tight bundle traps humidity in its core and the capsules inside it mold instead of drying and splitting.
- Hang the bundles upside down over a sheet or inside a paper bag Head down, in a dry airy place out of rain and direct sun. Sheet, tarpaulin or open box beneath. For a few plants, invert a large paper bag over the heads and tie it loosely at the stems so nothing escapes at all.
- Shake each bundle over the sheet every day or two A firm shake and a light tap on the stems empties the capsules that have opened since the last time. Repeat until a hard shake produces almost nothing, which usually takes one to three weeks.
Winnowing a very small seed, which takes patience
What lands on the sheet is not seed. It is seed mixed with capsule fragments, dried flower parts, leaf dust and pieces of stem, and sesame seed is small and light enough that separating it is genuinely fiddly work. Set aside a quiet hour and do it in stages. This is the part of growing sesame that nobody warns you about.
Start by sieving. Pass everything through a coarse sieve or colander that holds back stem and capsule pieces and lets seed through, then through a fine sieve or tea strainer that holds the seed back and lets dust and grit fall away. Two sieves in sequence remove most of the bulk in a couple of minutes and leave you with seed and light chaff of a similar size, which is what winnowing is for.
Then winnow. Pour the seed slowly from one bowl into another in front of a fan on its lowest setting, or outdoors in a light steady breeze, holding the upper bowl about eighteen inches (45 cm) above the lower one. The chaff is lighter than the seed and blows sideways while the seed falls straight down. Pour it back and forth four or five times over a wide sheet, and keep the fan low, since sesame seed is light enough to be carried off by an ambitious draft. Finish by picking the last fragments off a white plate in good light.
Yield, storage and keeping seed for next year
Be realistic about quantity before you give a bed over to it. A well-grown home row yields roughly two to four ounces of clean seed per square yard (70 to 140 g per square meter) in a good hot season, and a dozen plants gives you a jar rather than a store cupboard. Grown for next year's sowing seed and a few meals of something you cannot buy at that freshness, it earns its ground. Grown as a staple supply, it does not.
Dry the cleaned seed further before storing. Spread it in a single layer on a tray in a warm airy place, out of sun, for two or three days, and test it by pressing a seed with a fingernail. It should shatter rather than dent. Then store airtight in a cool dark cupboard. Sesame is high in oil and the oil goes rancid, so a warm shelf above a stove spoils it within months while a cool cupboard keeps it a year and a freezer keeps it several. Set aside the best-filled seed, from the lowest capsules of the strongest plants, as next year's sowing seed before you eat any. It stays viable two to three years.
What to record at harvest
Write down the date the lowest capsules first split, against the sowing date. That interval is the true length of the crop where you garden and it is the number that tells you next spring whether your season is long enough, and by how much. Record the cutting date too, and whether you were on time or a few days late, because being late is the commonest way a sesame harvest is lost and you will only correct it if you have written down that it happened.
Weigh the clean seed against the length of row you cut, and note how long the bundles took to dry and where you hung them, since a drying spot that worked once will work again. Mark which plants you took sowing seed from.