The short answer: ginger and turmeric grow well in coco peat, and growers move them into bags mainly to escape soil-borne rhizome rot. In trials, pure coir dust out-yielded coir blended with burnt rice husk, and coir matched peat and bark. Give each plant 12 to 20 litres of substrate, plant a 20 to 40 g piece with two or three buds, keep the feed weak (50 to 100 ppm N, EC around 1.8 to 2.3 mS/cm), hold the root zone at 25 to 30°C, and expect 1.5 to 5 kg of fresh ginger per bag depending on volume and feeding.
This article covers bag and trough culture of the two rhizome crops under a rain shelter, net house or polytunnel. Field figures appear only for comparison.
Why growers move ginger and turmeric into bags
Rhizome rot is the reason. Pythium soft rot (mainly Pythium myriotylum and P. aphanidermatum) is one of the most destructive diseases of ginger anywhere, with losses of 50 to 90 per cent in bad years in major producing areas. In Australia it appeared in the wet summer of 2007/08 and some growers lost whole blocks. The pathogen moves in soil, in surface water and in infected planting material, and it thrives where the soil stays saturated and warm. Bacterial wilt (Ralstonia) and Fusarium yellows are also soil- and seed-borne, and root-knot nematode can make a field crop unmarketable.
A bag of clean coco peat on a bench or on ground cover breaks that cycle. The crop never touches field soil, drainage is under your control, and if one bag goes down you remove it instead of losing the row. Under cover you can also start earlier and run later than the open field allows, which matters for young "baby" ginger sold at a premium.
The trade-offs: a bag has a small nutrient reservoir, so feeding has to be regular. Bags in full sun heat up fast. And nothing stops rot if you plant infected seed or overwater, so clean seed and drainage still come first.
Bag size and substrate volume
Ginger grows in layers, so depth matters as much as width.
| Container | Plants per container | Notes |
|---|---|---|
| 12 L nursery pot | 1–2 sprouted rhizomes | Used in a six-month greenhouse substrate trial. Fine for young ginger, tight for a nine-month crop |
| 19 L (5 US gal) fabric bag | 2 rhizomes | In a 2025 tunnel trial, 38 L bags gave more high-quality rhizome per plant than 19 L bags at the same density |
| 38 L (10 US gal) fabric bag | 3 rhizomes | The size most often recommended for three plants under protected culture |
| 40 × 24 × 24 cm bag (about 23 L) | 1 piece of 20 g | Kerala extension method. Up to 1.5 kg fresh ginger per bag |
| 60 × 60 cm lay-flat polybag | 1 piece of 40 g | Malaysian rain-shelter trial, 100 per cent coir dust, drip fertigated. 5.5 kg per plant at nine months |
| Minimum for any bag | – | At least 30 cm deep and 30 cm wide. Smaller bags stunt rhizome development |
For turmeric the published bag work is thinner. A grow-bag system in India uses about 60 g of seed rhizome per bag of pure coco peat under a net house, with 3 to 3.5 kg per bag as a realistic first-year figure and a best bag of 8.17 kg.
Open-top coir bags and slabs filled on site work the same way as fabric bags. See coco grow bag sizes and plant density for volumes and plant counts, and grow bags for the formats.
Coir alone or a coir blend?
Pure coir dust has the best record so far. In a nine-month rain-shelter trial, 100 per cent coir dust gave the highest rhizome yield (5,480 g per plant), and media with 70 to 100 per cent coir out-yielded media with 70 to 100 per cent burnt rice husk by up to 36 per cent. The explanation offered was air porosity: rhizomes need oxygen, and the rice husk blends held more water and less air. Gingerol content was the same across all substrates.
Coir against peat and bark is a draw. In 12 L pots, 100 per cent coir, 100 per cent peat, three peat–bark blends and 100 per cent bark showed no significant yield difference over six months.
Compost blends are common where growers want some nutrient buffering and lower fertiliser input.
| Blend (by volume) | Where it's used | Comment |
|---|---|---|
| 100% coir dust (coco peat) | Fertigated rain-shelter ginger, Malaysia. Turmeric bags, India | Highest trial yield. Needs complete fertigation from day one |
| Coir pith + coconut husk chips | Greenhouse grow bags, USA | Chips add drainage for a long crop. Ratio not published |
| 2 parts soilless mix : 1 part finished compost | High tunnels, US Midwest | Fill bags 40% with mix, add compost to 60%, hill with a further 10% later |
| 1 : 1 : 1 : 1 soil, sand, dried cow manure, coir pith | Kerala, India | Heavier and cheaper than soilless. Carries more disease risk |
| 3 : 1 : 1 coco peat, vermiculite and a third component | Black turmeric (Curcuma caesia) under shade net, India | 0.56–1.5 kg per pot. Different species, so a pointer only |
If you blend coir with chips, see coconut husk chips for grades. Use washed, low-EC coir for a rhizome crop: ginger is sensitive to salt and to fertiliser burn.
Seed rhizome size, pre-sprouting and planting
| Parameter | Ginger | Turmeric |
|---|---|---|
| Seed piece | 20–40 g with 2–3 buds (40 g, 4 cm long is a common trial standard). 75 g pieces for three-plant bags. Field growers use 113–227 g | 25–30 g |
| Seed treatment | Hot water at 50°C for 10 minutes, or a fungicide dip. Hotter or longer damages the buds | Same |
| Pre-sprouting | In moist sand or trays 20–25 days until shoots show, or until shoots reach 15–20 cm, then harden off 7–10 days | Optional, often planted direct |
| Planting depth | 5–7 cm of cover in a part-filled bag | About 4 cm |
| Density | One piece per 12–20 L. Three pieces 10–15 cm apart in a 38 L bag | About 60 g of seed per bag |
Pre-sprouting pays off under cover because a dormant rhizome in a cold, wet bag is the easiest thing to rot. Plant with shoots up, rhizome buried, shoot tips above the surface.
Topping up (hilling) in a bag
Field ginger is hilled three to five times a season. Covered too deep, rhizomes come out thin and elongated. Covered too little, they turn knobby and grow sideways. In a bag you fill to about 60 per cent at planting and add substrate as the shoots grow.
- US high-tunnel method: fill to 60 per cent, then add roughly 10 per cent more mix once plants are established.
- Kerala layering method: half-fill, plant, then add a layer every 22 days or so, up to three layers. Growers quote at least 500 g of rhizome per layer and 4 to 4.5 kg per bag from three layers.
Moisten top-up coir before adding it. A dry layer over a wet one wets unevenly.
Fertigation, EC and water
Ginger wants less feed than most greenhouse crops. In a coir pith and husk chip grow-bag trial with five nitrogen rates, 100 ppm N gave the highest fresh rhizome weight: 16 per cent more than 50 ppm, 205 per cent more than 200 ppm and 345 per cent more than 500 ppm. A second trial in the same programme put the best range at 50 to 100 ppm N. Field growers say it differently: high nitrogen grows leaves at the expense of rhizome, so they use low-N analyses like 10-20-20 and switch to potassium late in the crop to plump the rhizome and give a shiny skin.
| Stage | Fertigation and water |
|---|---|
| Solution strength | EC 1.8–2.3 mS/cm in a fertigated coir trial. Nitrogen 50–100 ppm |
| Months 1–3 | About 675 mL of solution per plant per day in three events |
| Months 4–7 | About 1,350 mL per plant per day in six short events. Rhizome bulking starts in month five |
| Last 1–2 months | Cut back hard (75 mL per day in the trial) and stop feeding and watering about a month before harvest |
| Soil-based bag mixes | Under 3 g of NPK per plant. All phosphorus and half the potassium at planting, nitrogen split at 1.5–2 and 3–4 months |
Rot is a free-water disease, so run drip on a timer, never let a bag stand in water, and raise bags off wet ground. For EC drift during the crop see coco coir pH and EC management.
Shade and temperature
| Condition | Figure |
|---|---|
| Root-zone target | 25.5–30°C (78–86°F) |
| Air range | 18–35°C. Below 13°C the rhizome goes dormant. Above 32°C expect leaf scorch |
| Shade | About 25 per cent in Kerala practice. 30–50 per cent cloth over tunnels in summer where the root zone passes 30°C |
| Turmeric | Shade-tolerant. Indian bag systems use simple net houses rather than polyhouses |
| Pythium risk | Warm, saturated media. In pot tests, disease developed readily with daily maxima above 30°C under overhead sprinklers |
Black bags in sun are the common mistake. They push the root zone past 30°C on a bright day, which stalls the rhizome and favours Pythium. White or fabric bags, shade cloth and bench spacing all help.
Harvest timing
Ginger is marketable as young, low-fibre ginger from 3 to 6 months and as mature ginger from 8 to 9 months. In the nine-month coir trial gingerol peaked at month six and fell afterwards, so young ginger is both tender and the most pungent per gram. Mature rhizomes add a large share of their final weight in the last month, so lifting a month early costs more than you'd think.
Field guides give 8 to 9 months in India and 10 months for best yield in Hawaii. Trimming the tops two to three weeks before harvest hardens the skin, and cured rhizomes need three to five days of airy drying before packing. Turmeric is a 270-day crop in Indian practice, harvested when the leaves yellow and lodge, though six-month varieties exist.
Yields from trials and demonstrations
| System | Fresh rhizome yield |
|---|---|
| Ginger, 23 L bag, one 20 g piece, soil–coir mix, Kerala | Up to 1.5 kg per bag |
| Ginger, bag with three 75 g pieces, soil-based mix, West Bengal | 1.5–2 kg per bag |
| Ginger, large sack, three layered top-ups, Kerala | 4–4.5 kg per bag |
| Ginger, 60 × 60 cm polybag, 100% coir dust, drip fertigated, nine months | About 5.5 kg per plant |
| Turmeric, coco peat bag, 60 g seed, net house | 3–3.5 kg per bag typical, 8.17 kg best |
| Ginger, open field, India | 12–15 t/ha (1.2–1.5 kg/m²) |
| Ginger, open field, Hawaii | 18 t/ha average, up to 32 t/ha |
| Ginger, treated trial plots, Queensland | 36.5–42.8 t/ha at early harvest |
| Turmeric, open field, India | 25–30 t/ha fresh |
A cross-check is the seed-to-crop ratio: commercial field ginger returns about 20 kg for every kilogram planted. The Malaysian coir figure (5.5 kg from a 40 g piece) is far above that, which is what a long season, clean media and precise fertigation buy you. Budget on 1.5 to 3 kg per bag in your first season and improve from there.
Reusing the substrate after a rhizome crop
Here the sources disagree, and the disagreement is about disease rather than coir. Indian extension advice is to use fresh mix every cycle and remove every rhizome fragment at harvest, because Pythium and Ralstonia persist in used media. A commercial turmeric system in coco peat reuses the same coco peat for up to five years and the bags for two or three cycles.
Both can be right. Coir holds its structure for several seasons. The question is whether the bag carried disease. If the crop was clean, screen the used coco peat, re-wet it, check EC and reuse it, ideally on a less sensitive crop. If any bag showed rot, the whole batch goes to compost or landscape use, not back into ginger. The general process is in reusing coco coir.
CVM Fiber and Industries in Kanyakumari, Tamil Nadu, India makes washed, unbuffered coco peat in 5 kg blocks and 650 g briquettes, plus grow bags, open-top slabs, coconut husk chips and custom blends. If you're setting up a rhizome crop under cover and want to talk through bag volume or a coir–chip blend, contact us.
FAQ
Can ginger grow in pure coco peat without soil?
Yes. In a nine-month rain-shelter trial, 100 per cent coir dust gave the highest rhizome yield of all substrates tested, about 5.5 kg per plant. You need complete fertigation from planting because coco peat holds little nutrient of its own, and the feed should stay weak, around 50 to 100 ppm nitrogen.
What size grow bag does ginger need?
Plan on 12 to 20 litres of substrate per plant and a bag at least 30 cm deep and wide. A 38 L (10 US gallon) bag takes three sprouted rhizomes and out-yielded 19 L bags per plant at the same density in a 2025 trial. A 19 L bag should hold two plants, not three.
How much fertiliser does ginger in coco peat need?
Less than most greenhouse crops. In a coir grow-bag trial, 100 ppm N gave two to four times the rhizome weight of 200 to 500 ppm N, and growth was best between 50 and 100 ppm. A fertigated coir trial ran at EC 1.8 to 2.3 mS/cm. Too much nitrogen grows leaves instead of rhizome.
Do I still need to hill ginger in a bag?
Yes. Fill the bag to about 60 per cent at planting and add roughly 10 per cent more substrate once plants are established, or add a layer every three weeks until the bag is full. Hilling keeps the rhizome growing upward and plump. Without it rhizomes grow sideways and knobby.
Does growing in bags prevent Pythium and bacterial wilt?
It removes the main source, which is infected field soil and the water moving through it. It doesn't help if you plant infected seed or let the bag stay saturated and warm, since both diseases are seed-borne as well as soil-borne. Treat seed, use drip on a timer, raise bags off the ground and remove any bag that shows rot.
How long does ginger take to harvest in grow bags?
Young, tender ginger is ready 3 to 6 months after planting, and gingerol peaks around month six. Mature ginger with firm skin takes 8 to 9 months, or up to 10 in cooler climates. Rhizomes add a lot of weight in the final month, so don't lift mature ginger early.
How much ginger can I expect per bag?
Published figures run from about 1.5 kg for one small seed piece in a 23 L bag, through 1.5 to 2 kg for three plants in a soil-based mix, to 4 to 4.5 kg per layered sack and about 5.5 kg per plant in a large fertigated coir bag. Budget on 1.5 to 3 kg per bag in your first season.
Can turmeric be grown the same way as ginger in coco peat?
Yes, and it tolerates more shade, so Indian growers use simple net houses. Plant 25 to 30 g pieces about 4 cm deep, or about 60 g of seed per bag in the commercial coco peat system, and expect a nine-month crop for most varieties. Realistic yields are 3 to 3.5 kg per bag, with a best bag of just over 8 kg.