Ginger (Zingiber officinale) is a swollen root—or, rhizome—that is consumed as a food, a spice or flavoring, and a medicine against nausea.
There are over 1.5 million tonnes of ginger produced in the world, but as a tropical/sub-tropical crop the main production areas are found in India and PR China (approx. 350,00 t each), followed by Indonesia, Nepal, Nigeria and Thailand (about 150,000t each).
Characteristics of Ginger Production
The plant itself comprises several upright, grass-like leaves that grow from the rhizome, which has both fiberous and thick roots. The plant steadily expands with the production of new rhizomes (the roots come first and produce the stalks from which leaves grow).
The characteristic odor and flavor of ginger comes from fragrant essential oils, particularly gingerols, found within the rhizome.
The success or failure of ginger production is determined by the health of the “seed pieces” (pieces of the rhizome) and the health of the soil. Diseases, particulary fusarium and pithium, and pests like nematodes can seriously reduce production.
All growers anticipate some losses every season due to disease. However most growers believe that a 10% losses in a patch are acceptable and, at times, some patches can experience over 80% losses. In Hawaii, the soil pathogen problem is so serious that it is normal to fumigate the soil with methyl bromide.
The Queensland bulletin on ginger production also cites crop establishment in Australia being anything from as low as 5% to up to 95% due to soil borne pathogens.That being said, it’s no surprise that disease-free planting material is highly desirable.
Can You Grow Ginger Hydroponically?
While at a hydroponics conference in Adelaide last year I was asked about growing ginger using hydroponics. I confessed complete ignorance, but this stimulated my interest to investigate the potential of using this production system—which is becoming well-established for many crops—for the less common goal of growing a root crop.
The first approach was to review the existing literature on the subject. I, however, only discovered three papers on the hydroponic production of ginger—namely Kratky (1998), Rafie et al (2003) and Hayden at al (2004)—and numerous articles on the world wide web that were how-tos without any research findings.
The Kratky paper proposes that the production of ginger using a non-circulating hydroponic method, in which essentially the plants were grown in plastic nursery flats filled with a growing medium comprised of peat, vermiculite and perlite.
The plastic nursery flats were suspended eventually some 4 cm above a static nutrient solution once the roots had moved through the medium into the solution.
The Hayden paper was similar to some respects, except that instead of a static nutrient solution the growing medium was suspended above a tank in which the roots grew, and the nutrient solution was applied as a fine mist using aeroponics.
The third (and simplest) system, explained in Rafie et al, used trays filled with a medium of coarse perlite. Plant spacing was 1.5 ft x 1 ft (1.35 x 0.3 m).
All systems appeared to work satisfactorily. The Hayden trial showed major disease problems when using peat as a growing medium, illustrated the importance of a growing medium (perlite in this case) for the rhizomes (as opposed to no growing medium), and demonstrated that heating the nutrient solution to 25ºC produced rhizomes that were 50 per cent larger.
The Kratky paper also showed low yields without the use of a medium over the rhizome and that the more medium volume the better. The Florida paper merely shows that the hydroponic system produced nearly double the yield of a field soil system.
In our experiments, since ginger is not grown in New Zealand and introducing it via quarantine can be a tedious (and expensive) exercise, we purchased imported dried ginger roots (rhizomes) from a local supermarket from Fiji (or Australia) and from Thailand.
It was unclear whether this might have been treated to prevent sprouting, but in fact it sprouted easily when planted in a moist growing medium in a greenhouse.
We started the rhizome pieces in small pots filled with coir in September (Fiji source) and November (Thailand source), and once they had produced a shoot and some roots they were transferred into large pots filled with coir (cocopeat) and with a single dripper nozzle to each plant.
A complete nutrient solution was applied with every watering, and the plants were grown in a greenhouse heated at 15ºC and ventilated at 25ºC.
In early May, it was decided to examine the plants to determine whether any ginger had developed, and we were gratified to discover that the system had worked successfully.
As one might anticipate, the early planting had produced the greater yield and there clearly could be some advantage in planting even earlier than September so that the plants would be much larger in mid-summer when growth potential is greatest.
Is this the way to grow ginger hydroponically? The answer (in my view) is a clear cut no. The more sensible solution would be not to use pots, but to grow the crop in beds filled with a good, well-drained growing medium (coir certainly fits this bill) using hydroponics.
The key factor would be to isolate the beds from the soil, either by using beds on benches or a layer of polythene film over the greenhouse floor. The importance of temperature is clear from the Arizona research, and this must pose the question of whether greenhouse production might even be an even better option in warm climates such as India or Australia?
Of course, the longer the plant is grown the higher the yield, but apparently the rhizomes also become more fibrous; so for candied ginger, the younger rhizomes are likely to be more desirable. If the crop is being grown for the oils alone, such as for flavoring ginger beer, then the oil content (and differences in chemical constitution) is likely to be influenced by genotype, possibly by harvest date, and by the way in which the crop has been grown.
This article was originally published in Practical Hydroponics.
Hayden A L, Brigham L A & Giacomelli G A (2004). “Aeroponic Cultivation of Ginger (Zingiber officinale) Rhizomes” Acta Hort. 659, 387- 402.
Kratky, B A. (1998). “Experimental non-circulating hydroponic methods for growing edible ginger”. Proceedings, 27th National Ag Plastics Congress. Tucson, Arizona, USA. Feb18-21, 1998. pp 133-137.
Rafie R A , Olcyk T, & Guerrero W (2003). “Hydroponic production of fresh ginger roots (Zingiber officinale) as an alternative method for South Florida.” Proc.Fla State Hort. Soc. 116, 151-2.