Transplanting Rice Seedlings Into a Tub or a Small Flooded Bed

Be honest about the yield before you choose a container

Rice is a field crop that has been squeezed into a tub, and the arithmetic is unforgiving. A wide container of about 20 gallons (75 liters) holds perhaps a dozen clumps, and a dozen well-grown clumps yield somewhere between a half and a full cup of finished white rice, after threshing and hulling have taken their share. That is one or two bowls at a meal. Nobody grows rice at home to eat through the winter. People grow it because a rice plant is a startling thing to watch, because the flooded tub is a small ecosystem in its own right, and because holding grain you germinated, transplanted, dried and hulled yourself changes how you look at the bag in the cupboard.

Once you accept that, the container decision gets easy. Choose width over depth every time. Rice roots occupy only the top eight inches (20 cm) of mud, so a deep barrel wastes most of its volume, while surface area is exactly what sets the number of clumps and therefore the number of heads. A shallow, wide vessel like a mortar tub, a stock trough or a lined half-barrel laid out flat beats a tall drum of the same capacity by a wide margin.

Mud, not potting mix

Fill the container with heavy soil to a depth of eight to ten inches (20 to 25 cm). Plain garden loam or a clay-rich topsoil is ideal. Avoid bagged potting mixes with a high bark or peat content: they float, they break down into a brown broth, and they will not hold a seedling upright. If your only option is a bagged mix, cut it half and half with the heaviest soil you can find.

A few days before transplanting, flood the soil and stir it thoroughly with a stick or your hands until it is a smooth, lump-free slurry with no dry pockets, then let it settle until the water above is clear and the mud below is soft. This stirring is not a nicety. It seals the mud so water stops draining away, it evens out the surface so no seedling sits proud and dries out, and it kills whatever weed seedlings had started. Leave the settled mud with about an inch (2.5 cm) of standing water on top and it is ready.

Mix a modest amount of general-purpose fertilizer into the mud at this stage, roughly a third of what a leafy vegetable would get in the same volume. Rice given a rich start grows lush, floppy leaves and blows over in the first summer storm. It is far better to start lean and feed later when the plant is carrying heads.

Do not use a container that has held weedkiller, wood preservative or road salt. A flooded tub concentrates residues, and rice roots sit in that water for four months with nowhere else to go.

Setting the seedlings in

Transplant on a still, overcast day if you can pick one. Seedlings lifted from a tray have almost no root left after the mud is rinsed off, and a hot windy afternoon will crisp them before they anchor. Lift a handful at a time and keep the rest of the tray wet while you work.

1. Separate into small clumps of two to three seedlings Rice is planted in clumps rather than singly. A clump of three establishes faster and shades out weeds sooner than one seedling on its own, and each stem still tillers into a fan of its own.
2. Push each clump about one and a half inches (4 cm) into the mud Two fingers do the job: pinch the base of the clump, push straight down until the mud closes over the white part of the stem, and withdraw. Planted too shallow the clumps float free within a day. Planted much deeper the plant delays tillering for a week or two.
3. Space clumps six to eight inches (15 to 20 cm) apart That looks absurdly generous when the seedlings are four inches (10 cm) tall. It will not look generous in high summer, when each clump has spread into a fan of fifteen or twenty stems and the surface is closed over.
4. Keep the water shallow for the first week Hold about an inch (2.5 cm) over the mud until you see new upright growth, roughly five to seven days. Deep water at this stage lifts the clumps out and floats them across the tub.
5. Raise the water once they stand up When the seedlings are visibly growing rather than just standing, bring the water to two to four inches (5 to 10 cm) and keep it there through the main growing season.

Why flood it at all, and what to do if you cannot

Rice does not need standing water. It is a grass, and it will grow perfectly well in soil that is merely kept constantly wet, the way you would keep a bog garden. Every rice-growing culture floods anyway, and the reasons are practical rather than botanical. Standing water smothers nearly every weed that would otherwise compete, and weeding a densely planted rice bed by hand is miserable work. The water also buffers temperature, holding warmth overnight in a cool spring and keeping roots from cooking in a heatwave. And it discourages a range of soil pests that cannot cope with waterlogging.

So if a watertight tub is not practical, grow it wet instead of flooded. Use an ordinary large container with drainage, stand it in a shallow saucer of water, and never let the surface dry. You will get rice. You will also get far more weeding, slightly slower growth in a cold spell, and a plant that is less forgiving of a missed watering, because a flooded tub can survive a forgotten weekend and a wet pot cannot.

Record the date you transplanted, the number of clumps you set, and the layout, sketched or photographed from above. Rice clumps merge into an unreadable mass by midsummer, and when you are trying to work out later why one corner headed early or one clump lodged, the only way to reconstruct it is a note made on planting day.