Gadenin日本語Get the appThe whole run at a glance
Radish shoots have three phases and no seasons. Days zero to three are the blackout, when the tray is covered and the stems stretch. Days four to seven are greening, when the tray is in light and being bottom watered daily. Days eight to ten are the harvest window, which is three days wide and closes into bitterness rather than staying open.
The schedule below assumes a room at 65 to 70F (18 to 21C). Warmer pulls every stage forward by a day or more, cooler pushes it back by two or three. Work from what the tray looks like rather than from the day number when the two disagree, because the tray is always right.
Because there is no regrowth and no salvage, the only decisions you make in ten days are when to uncover and when to cut. Everything else is watering and leaving it alone.
| Day | Phase | Action | What you should see |
|---|---|---|---|
| 0 | Sowing | Fill, pre-water, level, sow, press, cover | An even single layer of seed, seeds nearly touching |
| 1 | Blackout | Lift the cover, look, replace | Seed swollen and split, first white root tips |
| 2 | Blackout | Mist only if the surface has paled | White root hair halos, often mistaken for mold |
| 3 | Blackout | Check stem height under the cover | Pale stems 1 to 2 in (2.5 to 5 cm), cover starting to lift |
| 4 | Uncover | Bottom water, move to indirect light | A brief wilt, then the mat stands up again |
| 5 | Greening | Bottom water, full light, quarter turn twice | Seed leaves opening, color coming up fast |
| 6 | Greening | Bottom water, keep air moving | Leaves flat and green, stems 3 in (8 cm) |
| 7 | Greening | Bottom water, check base for soft stems | Deep green mat, first tray is cuttable |
| 8 | Harvest window | Stop watering the evening before cutting | Stems 3 to 4 in (8 to 10 cm), mild and sweet |
| 9 | Harvest window | Cut with scissors above the medium | Peak flavor, clean and distinctly peppery |
| 10 | Closing | Cut now if you have not | Heat climbing sharply, leaf edges darkening |
Days zero to three: covered and left alone
The blackout is the least demanding part of the run and the easiest to overdo with attention. Under a solid cover the humidity holds, and most trays need no water at all in these three days. Lift the cover once daily for half a minute, which is enough to exchange the air and let you see what is happening.
Look for two things. Free water standing on the surface means you pre-watered too heavily and should leave the cover slightly ajar for an hour. A surface that has gone from dark to pale gray means it is drying and wants a light mist.
The height check on day three is the one real decision. One and a half to two inches (4 to 5 cm) of pale stem means uncover; anything less means cover it for another day, and a cool room routinely needs day four or five.
If the cover has been on for five days and the stems are four inches (10 cm) of thin white thread, uncover immediately and expect a floppy mat. It is still edible and still worth cutting, but shorten the blackout by a full day on the next tray.
Days four to seven: light, water, air
Uncovering day is the busiest point in the run. Bottom water first, then put the tray somewhere bright but out of direct beams, and expect the mat to sag for an hour or two before it recovers. From the next day it takes full light for twelve to sixteen hours.
From here the tray wants water every day, always from below, and it wants air moving in the room. Lift the tray each morning to judge whether it is light and needs a drink rather than looking at the surface, which tells you very little once the mat has closed over.
Color arrives fast. A tray that is pale yellow-green on the morning of day four is usually properly green by the evening of day five. If it is still yellow on day six, the light is too weak rather than something being wrong with the crop.
Days eight to ten: cut, and clear the tray
The tray becomes cuttable as soon as the seed leaves are flat and fully green, and it stays good for about three days after that. Stop watering the evening before you plan to cut so the mat is dry at the base, then shear the whole thing half an inch (1 cm) above the medium in one session.
Nothing regrows. Tip the root mat and spent medium into the compost the same day rather than leaving a wet mat sitting in a warm kitchen, and wash the tray in hot soapy water before it is used again.
If you cannot cut on the day it is ready, cut anyway and refrigerate. Shoots held in the fridge for two days are far better than shoots left standing in the tray for two days, where the heat and the fiber keep climbing.
Overlapping trays for a steady supply
Because a tray is a single crop, continuous supply is a matter of arithmetic rather than technique. A ten-day cycle and a harvest window of about three days means a new tray every four to five days gives an unbroken run with a small overlap, which is what you want.
Two trays on a rotation are enough for a household eating shoots two or three times a week. Three trays on a four-day interval keeps a bowl in the fridge permanently. Sowing all your trays at once instead is the classic first mistake: you get more shoots than you can eat in three days and then nothing for a week.
Stagger the shelf as well as the calendar. Keep the covered trays somewhere out of the way and the greening trays under the light, so the two jobs do not compete for the same spot.
| Setup | Sowing interval | Trays running | Typical supply |
|---|---|---|---|
| Occasional | As wanted | 1 | One bowl every ten days |
| Steady household | Every 5 days | 2 | Fresh cut twice a week |
| Continuous | Every 4 days | 3 | Always something in the fridge |
| Heavy use | Every 3 days | 3 to 4 | A cut tray most days |
Keep a running sheet across trays
One line per tray is enough: sowing date, seed weight, the day you uncovered, the day you cut, the cut weight and one word on flavor. Kept across a dozen trays this becomes the schedule for your own home rather than a general one.
The two things it settles quickly are your true cycle length, which is usually a day or two off the standard figures because of your room temperature, and your correct sowing interval. Both drift with the seasons as the house warms and cools, and a running sheet catches that shift long before you notice it as trays arriving at the wrong time.