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Tigernuts and its cultivation

WE LIKE HORCHATA, BUT DO WE KNOW HOW TIGERNUT IS GROWN?

We are at the right moment in which in Spain we are watching the thermometers more than ever. The heat falls with all its weight and that weight is best carried on the beach, pool or … with a cool horchata !! Today in Gardenprue we talk a little about the cultivation of tigernut, with which this drink is made.

We have been wanting to talk about tiger nuts for a long time and we have decided to do it today for a very minority crop in Spain and in the world. Practically all tigernut cultivation is centered in the Valencian Community due to its long tradition in the production of horchata. Other uses of tigernut are known to feed livestock in some countries but little else. We are going to get a little into the most common conditions and practices in the cultivation of this small tuber.

THE WEED TIGERNUT ?!

If we had to talk about the genus Cyperus we could spend days. There are a few hundred species and many of them have something in common: They are very persistent in the field and grow easily, consuming many resources, especially if the availability of water is abundant. The tigernut can be one of them and therefore, if you grow it, the advantage is more than clear, but if you grow something else, the presence of species of the genus Cyperus can be a serious problem that is difficult to control, including the tigernut.

Detail of the chufa plant. Photo of NY State IPM Program at C

TIGERNUT CHARACTERISTICS

Botanically it is known as Cyperus esculentus L . It is a perennial plant although its cultivation in Spain is done as an annual. It forms very thin rhizomes that produce, at their ends, the tubers that we take advantage of to make the delicious horchata. That’s right, the part that is used is the tubers, although apparently it could look like a dried fruit such as an almond or similar. In fact in English one of the names it has is Almendra de tierra (earth almond).

The tuber (the tigernut as we know it) is the size of a  wrinkled bean , approximately 2 cm long and although its outer layer or epidermis is brown in color, its inner pulp is cream-colored, then the color that acquires the so precious and fresh drink of the summer.

The plant, morphologically, is not very attractive and it is very easy to confuse it with a multitude of herbaceous species, especially in the vegetative part since it has a very common shape. Lanceolate leaves no more than half a meter long by half a centimeter wide, with an inflorescence in the form of small yellow spikes. In Spain, it does not come to fruition most of the time due to lack of temperature. As we will see later, it is from warm regions although with soft registers, not extreme.

Detail of the fruit, the tigernut. Photo from Wikimedia commons

TIGERNUT GROWING CONDITIONS

 LET’S START WITH THE WEATHER

As we just mentioned, it is from hot climates. In fact, it takes about 5 months without frost for vegetative growth to occur without problems. One of the requirements for the formation of tubers to be adequate is that the temperatures are distributed gradually over time. We get with this, the thickening of the tubers. Hot but extreme climates are not good. As indicative data, the average temperatures should range between 12ºC (minimum temperature for tuber sprouting) and 25-28ºC, the latter being for which the plant stops its vegetative growth and flowering occurs. Irrigation requirements are abundant and therefore, high humidity, will greatly help the development of the plant. The proximity of the sea in the Levantine area makes this crop ideal as is logical.

SOIL IS THE GREAT LIMITING FACTOR

The edaphic conditions are the most tricky. The soil we need is of high quality for proper cultivation. First of all loose and light soils . The main reason is obvious: easy harvesting of the tubers. In caked soils (loamy, filthy), a lot of buried tuber can be lost without the possibility of removing it and the cost of harvesting is enormous due to the great difficulty. For this reason, soils with a certain sandy fraction are the most suitable.

Apart from the texture, they must be very well nourished because tigernut is considered demanding in terms of nutrient consumption . And as if that were not enough, we also need very good drainage , absence of stones, zero or practically zero salinity (this is the most complicated in the lift) and a sufficient water retention capacity to allow more or less constant humidity. Without a doubt, a headache. Of course we are talking about the optimum, that we do not forget.

IRRIGATION

Another important factor is irrigation, which will largely depend on soil conditions. The summer months are obviously the ones with the highest water requirements. Even so, a good level of humidity in the soil must be maintained throughout the growing period without flooding the root zone. The way to achieve this is with frequent waterings that allow a good assimilation of the water by the soil, maintaining a humidity that is maintained within the limits of field capacity and wilting point .

CULTIVATION CALENDAR

PLANTATION

The tubers are grown between March and May (depending on the weather), when temperatures start to improve substantially after winter. Preparing the land prior to planting is key. Well-defined ridges about 20 cm high with a spacing of 60 cm with a sowing depth of 6-8 cm according to data from the Chufa de Valencia denomination of origin.

HARVEST

What is most surprising about tigernut cultivation is the practice of burning it before harvesting it. To collect the tigernut, the aerial part has to be allowed to dry completely and become rotten. This occurs at the end of the year (December) when it is collected. Burning is a common practice that has been going on for years but not always. For several generations, agriculture was a system of cyclical use because there were no large productions. They had a bit of everything, livestock, crops, etc. The tigernut “straw” was used for the roofs of the barracks, as a bed for livestock and even for compost . Currently there is not much outlet for this by-product and it is burned just before harvesting.

Harvesting is currently completely mechanized with a combine that sweeps cutting the ridge from below and a subsequent screen.

WASHING, DRYING AND RIPENING OPERATIONS

After harvesting, postharvest curing or maturation occurs. It is what will give the tigernut the sweetness and aroma that will come to us in the future horchata. First , the tubers are washed and separated from the roots . This is followed by drying, spreading the tubers and moving them very frequently so that the drying is optimal and that no fungus and rots appear. It has to reach a humidity close to 10%. During all this drying process (it lasts for months) there is a degradation of the starch to sugars (as a very mild fermentation), an important process for the aroma and final flavor of the horchata that I am drinking at this moment while I finish writing this article . Delicious!

Photo from: chufamix.wordpress.com

To finish, we leave you an interesting video where it is explained in detail in the video, everything about the cultivation of tigernut. If an image is worth 1,000 words, then a video……

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