Cultivating saffron is an agricultural practice that is making a strong comeback in our countryside. It is a flowering plant derived from a bulb that yields a precious spice, highly valued in commercial markets. With the return of youth to agriculture, producing saffron pistils can be a highly appealing crop choice. This is particularly valid in rural areas and on smaller plots of land that don’t require significant material investment. Of course, cultivating saffron can also be driven by simple passion, given the beauty of its flower. It can thus be planted in domestic gardens without expecting large yields.
In this article, we’ll introduce you to saffron and its botanical peculiarities. Additionally, we’ll explain the cultivation techniques typical of our regions.
Saffron: Botanical Background and Origins
Saffron, scientifically termed Crocus sativus, is a plant belonging to the Iridaceae family. The term crocus comes from the Greek kròcos, meaning “thread”, recalling the long and typical thread-like stigmas of the saffron flower. The Crocus sativus species is the most cultivated to obtain the prized spice. In Italy, the wild Crocus vernus species (wild saffron) is also found in almost all regions, preferring cool, grassy places, woodland clearings, and blooms from March to June. Saffron is an ancient plant originating from Asia Minor, although it was known in India and China. The earliest written record in which it appears is an Egyptian papyrus from the 15th century BC. It’s also mentioned in the Bible, in the Song of Solomon, and by authors like Homer, Hippocrates, and Pliny the Elder. The introduction of saffron to Europe dates back to the 8th century, brought by Arab conquerors. In Italy, the cultivation of this spice spread mainly in the Center-South: Abruzzo, Sardinia, Sicily, and Tuscany. Today, Italian production mainly concentrates on Abruzzo and Sardinia. Iran is the world’s largest producer, followed by Spain, Greece, and India.
Botanical Characteristics of Saffron
The peculiarity of the saffron plant is that it originates from a bulb (tuber), similar to tulips, daffodils, or Jerusalem artichokes. The saffron bulb has a very solid and compact texture and is white in color. It also has a circular shape and a flattened appearance. The bulb has a diameter ranging from 3 to 6 cm. Another characteristic is the covering of filamentous tunics of dark cappuccino color, which are gathered at the top in a tuft. Under the tunics, there are 2-3 buds that develop into leaves and flowers and serve as an embryo for new bulbs. The bulb has adventitious roots, white and filamentous. They are up to 20-25 cm long, have mycorrhizae, and are poorly branched. They cease their activity when the leaves start to turn yellow. In the lower part of the bulb, there are also some contractile roots. These push the bulb deeper to meet the plant’s growth needs. The leaves and flowers, which are wrapped in a white spathe, emerge from the ground together shortly after late summer planting. The spathe is a transformed leaf that wraps around the flower and its base. It consists of 3-4 layers of very thin white tunics. The tunics have the consistency of a film similar to that which wraps around garlic. They tear at the tip and release the leaves, numbering from 9 to 11. The number of leaves that a saffron bulb can produce depends on the size and vitality of the buds. The leaves are narrow in bunches, almost triangular in shape. They are up to 40 cm long and 2-3 mm wide, with an entire, papilliform margin. The upper side of the leaf has a lighter central groove, and the lower side shows two parallel grooves with transparent prominences. The color is intense green.
Saffron flowers typically have a pinkish-purple color. They are often seen closed in a tube, but they open at the first morning sun. They have the shape of a bell and consist of:
- 6 tepals, fused into a tube at the base;
- 3 stamens with yellow anthers;
- 3 filamentous stigmas of crocus red color, with the enlarged apex shaped like a trumpet. These unite into a style, colorless, terminating in an ovary located underground where the seeds abort.
Usually, the appearance of the first flower precedes the leaf emergence (phenomenon of hysteresis). However, the leaves appear before the flower opens. The floral axis emerges from late October to mid-November. The saffron flower’s vibrancy is due not only to its bright color but also to its few leaves. The floral stigmas are the precious part of saffron. They are the reason for its cultivation, being the only useful part of the plant. These red stigmas are 3-4 cm long, elastic, and tangled. When chewed, they stain the saliva a deep yellow. They have a characteristic bitter-spicy taste with a strong aromatic odor that emerges upon drying.
Saffron’s Biological Cycle
Before delving into the details of how to cultivate saffron, it’s essential to explain the plant’s biological cycle because the agronomic interventions to be carried out vary depending on the life stage we are in. Here are the different phases in summary:
- Resumption of bulb activity;
- Bulb germination;
- Development of leaves and flowers;
- Development of new bulbs;
- Reproductive phase;
- Harvesting new bulbs;
Resumption of Bulb Activity
This moment begins with transplantation, which in our country usually takes place towards the end of August. From the planting, the apical buds become active and start to develop.
The vegetative recovery phase ends between late September and early October. The apical bud forms a cylindrical organ, a real protective sheath. The sheaths stop their vertical development when they emerge from the ground, and the buds of the flowers and leaves begin to form.
Development of Leaves and Flowers
This phase begins in October and ends in the first days of November. From the protective sheaths, the leaves begin to emerge, surrounded by the spathes, which protect the flowers. A floral shoot can contain from 2 to 5 flower primordia inside.
Saffron flowering occurs throughout the month of November and coincides with the harvesting period. It lasts for 15-20 days, a period called “mantle days”.
Development of New Bulblets
Immediately after flowering ends, i.e., at the end of November, the development of new bulblets begins. This phase covers a very long period, from December to February. During this long period, the mother plant has an intense vegetative activity, producing leaves and roots. Through these activities, reserve substances are accumulated, which are needed for the subsequent development of new bulbs. During this period, it’s important that the plant finds a good amount of organic matter in the soil, sufficient moisture, and favorable climatic conditions. Under these conditions, a balanced and lasting photosynthetic activity is guaranteed. It’s also important to keep weed presence under control through periodic weeding. This prevents the reduction in the quantity and quality of the newly produced tuber bulbs.
In early spring, the saffron plant transitions from the vegetative phase to the reproductive phase. The plant seems to be entering a resting period, but important generative processes occur inside it. These processes lead the apical vegetative meristems to transform into root or flower buds. During this phase, the plant has a high energy and water demand, ideally requiring a rainy spring season. Water helps in the growth of the newly formed bulbs. In areas like Sardinia, where there is a risk of low precipitation even in early spring, emergency irrigation is necessary.
Harvesting New Bulbs
Between May and June, the plant’s activity decreases, leading to the yellowing and drying of the foliage. At the end of this period, the new saffron bulbs are harvested, which will be used for late summer planting.
Soil and Climatic Needs
A significant advantage of cultivating saffron is its ability to survive both winter’s low temperatures and summer drought.
Despite this characteristic, let’s outline a climatic trend favorable to the crop throughout the year. Late summer rains after bulb planting are very beneficial. Water promotes root formation and growth. As mentioned, a rainy season at the beginning of spring is important. Conversely, incessant rains and water stagnation in autumn and late spring can be detrimental.
Saffron adapts well to different types of soil, as long as they have a good amount of organic matter and do not cause water stagnation. The ideal range for the soil pH is between 6 and 8. To start a new saffron cultivation, it’s ideal to use new soil, never previously cultivated with saffron and at rest for at least a year. Crop rotation is important for successful production since saffron is a perennial crop. For example, in the production regulations for Sardinian Dop saffron, a 4-year period for cultivation is indicated. Additionally, the bulb cannot be replanted on the same soil for another 4 years. In crop rotation, other tuber or root crops should be avoided. These include crops like potatoes, onions, garlic, carrots etc. The soil should be prepared in advance, with plowing to a depth of at least 40 cm, to be done in autumn. After plowing, the soil is left to rest, and if needed, fertilization is carried out.
Saffron greatly benefits from the presence of organic matter, especially aged and matured. Therefore, fertilization might not be necessary if abundant manuring has been done in previous years for other crops. Mature manure is the best fertilizer but should be applied only if the soil is genuinely poor. Manure can be spread on the soil after plowing at a rate of 3 kg per square meter.
Saffron bulbs intended for planting are harvested in June and subjected to careful sorting. The sorting involves the separation of bulbs, keeping aside those suitable for reproduction and flowering, with a nice apical bud. Typically, bulbs with a diameter not less than 2.5 cm are kept. Smaller, misshapen, signs of decay, or rodent-damaged bulbs are discarded. The selection of bulbs concludes with an initial “cleaning,” meaning the removal of the first layer of dry tunics, leaving the shiny inner ones.
The larger the bulbs, the greater their reproductive capacity, thanks to a greater presence of reserve substances. For this reason, saffron cultivation is renewed every year with bulb selection. In theory, it could remain directly in the soil for several years, but to the detriment of the quality of the final production. The well-cleaned bulb should be stored in a dark, dry place, awaiting transplantation. Of course, this refers to an already initiated saffron cultivation that is being renewed. If starting for the first time, bulbs need to be acquired from the market, seeking specialized retailers.
Planting the Saffron Field
In our country, planting the saffron field occurs in the second half of August. The soil is freshly milled to make it clean and level. Then the bulbs are cleaned by removing the outer tunics before planting. Planting begins from one side of the field, marking a straight furrow with a triangular hoe. The furrow should be about 15 cm deep and 15-20 cm wide. Bulbs are placed aligned in this furrow, next to each other, with the tuft of the tunics facing upwards. After the first furrow, the second is started, banking with soil from the first one, repeating the bulb placement. After the fourth furrow, a gap of about 50 cm is left, and the process is restarted. This way, 80 cm wide beds are obtained, with four rows of bulbs and 50 cm wide walkways. This structure can be organized differently, for example, with 2 or 3 rows. Fifteen days after planting saffron bulbs, the beds are leveled using a rake, straightening the furrow edges and deepening the walkways.
As we’ve seen, saffron flowering starts from the second half of October, which is the time for harvesting operations. The flowers emerge from the cluster of leaves, initially closed in a tube and open completely within 24 hours. Harvesting must be done early in the morning when the flower is still closed. It shouldn’t extend beyond 9-10 am. Harvesting open flowers jeopardizes the final quality of the product, risking damage to the stigmas. That’s why it’s important to visit the field every morning to pick the flowers formed during the night.
The harvesting technique, assuming a 4-row bed, involves walking along the path between the furrows, with a basket under the arm, picking flowers from 2 rows at a time. The flowering period lasts about 10 days, and it’s during this time that maximum effort is required for successful saffron production.
Processing Saffron After Harvest
Once the flowers are harvested, the red stigmas must be collected within the day, so the operations start immediately after returning from the field. Separating the stigmas from the flower requires great skill, precision, and speed. The stigma should be detached at the right point, where the red color ends. The freshly selected stigmas are then placed in a flour sieve and dried over coals near a fireplace for 15-20 minutes. This phase is very delicate and determines the quality of saffron. The drying should reach the point where when pressed between the fingers, they don’t crumble completely, maintaining good elasticity. At the same time, they must be dehydrated enough to avoid fermentation. The color of saffron should be a beautiful purple-red, and the aroma should be distinct. The final product obtained is stored in canvas bags or ground and placed in sachets. If done correctly, saffron can be stored for years, retaining its aroma. At the end of this lengthy article on how to cultivate saffron, stay tuned for future discussions on its uses and properties. If you want to buy quality saffron, you can find it here.