Saffron Cultivation
Cultivating Saffron in the Southern Hemisphere
Saffron Crocus Corms must be prepared for the Southern Hemisphere by giving the corms a temperature treatment. This treatment lasts from August to December/January and the corms do dry out somewhat during this period, therefore, no or hardly any flowering can be expected during the initial blooming period. The corms will continue to grow and multiply and will produce flowers the next season. Experience has shown that the vitality of smaller corms after the temperature treatment is even better than the larger ones, which means that these corms adapt sooner to the climate of the Southern Hemisphere, therefore, we recommend starting your cultivation with a corm size of either 9/10 or smaller.
Climate
When cultivating Saffron, we need an explicit climatological summer and winter with temperatures ranging from no more than 35˚C or 40˚C in summer to about -15˚C or -20˚C in winter. This is why Saffron can be cultivated in dry, moderate, and continental climate types but not in tropical or polar climate types. Cultivating Saffron in areas with dry and hot summers is not a problem as Crocus sativus is a heat-tolerant bulbous plant. In extreme winter temperatures, the leaves could dry-freeze, causing the corms to develop less and therefore bloom less and provide less saffron. If extreme frost threatens to attack your saffron fields it would be wise to cover the plants with straw or fiber cloths until the frost eases out. During dry climatological circumstances in springs time, irrigation is essential. During this period regular rainfall is good for the development of the corms, as it means a higher yield of flowers and cormlets(daughter corms).
Soil
The Crocus sativus can grow in several different soil types but thrives best in calcareous, humus-rich, and well-drained soil with a pH between 6 and 8. Saffron Crocus corms can be grown in dry or semi-dry soil types, it is important that during periods of drought in autumn and in spring that you need to irrigate the land. If your Saffron corms are planted in wet or semi-wet soil types you must ensure that your land is well-drained to prevent the corms from rotting or getting infected during periods of wet weather.
Planting
When it comes to planting saffron corms for the first time choose a virgin piece of land where no other tubers or Saffron corms have ever been planted before, if possible (if not, at least none in the past ten years). Before planting we advise to till the soil 20 to 50 centimeters deep to keep the planting beds loose and well-aired, incorporating organic fertilizer during the process. Planting corms on raised beds is ideal for ensuring irrigation and drainage. Irrigation should be minimal once the corms started growing leaves. Planting is done in the first two weeks of March to Mid-April, either by hand or by machine. Harvesting comes at the end of May to mid-June, roughly eight weeks after planting. Saffron crocuses like full sun and should be planted in the dry open fields rather than in the shade. Usually, corms are planted between 7-15 centimeters deep into the soil. The deeper they are planted, the lesser the corms multiply, the lesser the harvest, but the higher the blossoms' quality.
Seedbed system
D) Width of the seedbed 80 cm - 120 cm
E) Width of the walkway 25 cm
F) Height of the seedbed 15-35 cm
A) Planting depth 7-15 cm
B) Row spacing 15-20 cm
C) Distance between the bulbs 5-15 cm
Notes:
Raised bed width of 80 cm you can plant 3 rows .
Raised bed width of 120 cm you can plant 4 rows.
Observing the row system in planting corms is very important as illustrated in the image above. Each row is ideally 15 to 20 centimeters away from each other. Firstly dig the holes in the first row and fill them with corms. As you dig your second row use the soil that you dig up to cover the corms in the first row and so on. Keep your rows raised for enough drainage and ventilation. Between each block of rows leave enough space to create a pathway to walk between your blocks so it is easy to navigate along the crocus field as you work to weed, water, and later on the harvest.
Spacing
Spacing between corms is largely dependent on their sizes. Spacing depends on how often grubbing is scheduled. Grubbing refers to the complete removal of Saffron corms from the ground the separate the mother corms from the cormlets that have formed and store them for the next planting season. Biennial grubbing requires a spacing of between 5-10 centimeters between each corm, for a longer period make it between 10-20 centimeters between each corm.
Pests
Protective measures have to be taken against birds, rodents, and rabbits. Corm rot, leaf rusts, nematodes, and other pathogens must also be prevented from affecting the saffron crocus plants.
Grubbing
The corms of your saffron plant stay good for growing for up to four years and in the fifth year, they need to be grubbed. Once the Saffron leaves turn brown and wilted, the corms are dormant and are ready for grubbing. The fields are then upturned using a hoe or a plow machine and the corms are collected manually. The corms are then cleaned of unwanted seeds and bulbs, and new planting materials are classified according to size. The corms must not stay out in the sun for longer than a couple of hours. The sorted corms have to be stored in a dark, dry but well-ventilated place until the next planting season.
Weeding
Removing weeds requires a tedious, manual method especially if you are dealing with root weeds. Although machine weeding may be used in saffron cultivation there is a danger of harming the bulbs, therefore most farmers prefer to do it the traditional way. The longer the weeds stay in the saffron beds, the more difficult they become to remove, so it is better to deal with them the soonest. When Saffron leaves have withered but it is not time yet for grubbing, remove the brown leaves to spot the weeds easily.
The Saffron harvest
In the middle of May, saffron flowers begin to blossom and the blooming season lasts for about three weeks. There occurs a period of intensified blossoming called “blanket days” which last two to six days. Blooms that appear during the night must be harvested at dawn the very next day until noon time to avoid the petals from wilting. It is best to harvest blooms that are still “sleeping” or closed to ensure high-quality saffron threads.
Drying
After the stripping immediately comes to the drying, also known as the toasting, which is done daily until the last thread has been dried. Because they are exceedingly humid, the harvested stigmas are dehydrated by toasting at a temperature not higher than 60˚C, utmost care must be taken so that the threads are not overdone. Therefore the “toaster” known as the person appointed to do the task has a very delicate role in the production of quality Saffron spice. After the toasting period, the threads will reduce their size and weight extremely, down to 80% of the original size and weight. Five kilos of fresh stigmas yield a mere kilo of dried, vivid crimson threads. Stigmas can also be dried over hot coals or in an oven. Spread out the fresh threads on a wire mesh lined with baking paper and place them in the middle of the oven. Turn to heat to 50˚C, observing the thread keenly for 10-20 minutes until they are dry enough to fall away from each other. For bulk drying, saffron threads are placed in a room heated at 30˚C to 35˚C for 10-12 hours. A method known to be more modern is to use a dehydrator, with a temperature set at 48˚C for 3 hours. The length of drying time depends on the number of threads to dry. But the important thing is that they are not overdried because that will reduce the quality and price of the saffron threads.
Stripping
When the blooms are harvested they are brought to the “stripping” zone where the stigmas or threads are carefully removed manually and painstakingly. The white and yellow parts of the stigma are not to be included in the cutting, just the red parts.
Storage
If the threads are dried they turn into vivid dark red, with the tips being dark orange. They are then cooled and wrapped in tissue or foil and placed inside airtight jars, covered and kept in a cool, dark corner for at least thirty days before they are ready for use. They can be kept in that nook for a year and would still be in good use for the flavoring dishes.
Plant cycle in the Saffron cultivation
Saffron corms undergo stages of activity, transitory, and dormancy. The activity period begins when they are planted and they grow roots, shoots, leaves, and flowers. The transitory period occurs when the corms become mother corms and produce new bulbs or corm lets. The dormancy period is when the corms reach a mature stage and are no longer producing new bulbs, this stage is characterized by wilted leaves and dried-up roots. The corms will then need to be dug up and allowed to rest for some time before they can be replanted to produce again. As to the planting area, it is very ideal to let a Saffron field “rest” for at least ten to twelve years after a cropping cycle has been maximized to recover or refresh. It is best to move to a virgin field or a refreshed field to start a new cycle. This will ensure to give you good yields for another term.
Bulb size
Corms are sorted and graded according to their sizes. The sizes of a corm will therefore determine its yield. Years of experience have resulted in the conclusion that the larger the mother corms the more progenies it produces, meaning the higher the yield of flowers and stigmas in the first year of planting.