Saffron is the spice made from the stigma of the crocus (Crocus sativus). You will need quite a number of crocuses to make cultivation for the purpose of obtaining saffron worthwhile. However, if you have enough space, a polytunnel could make crocus growing easier, as the sunny, warm and well-drained conditions inside a polytunnel will be perfect environment and could allow for earlier blooms. Since saffron is one of the most expensive spices in the world by its weight, this may be one crop that is well worth growing at home.
Saffron crocus bulbs can be found through many online retailers. Place bulbs in the beds in your polytunnel or in a sunny and sheltered location outside at a depth of around 8-12cm in a good quality, rich soil. The addition of some grit can aid with good drainage in denser soils and ground up charcoal may help provide the optimum growing conditions for these flowers. Saffron crocus bulbs are usually planted in autumn and will flower in autumn the following year. You should aim for a spacing of around 10cm between your crocus bulbs.
Bear in mind when making the decision to grow saffron crocuses that each bulb will produce only one flower and each flower will produce only three tiny stigmas. 50 to 60 crocus bulbs will produce only one tablespoon of saffron. So this is quite an investment of both time and space. That said, these bulbs will multiply rapidly, so your stock will quickly grow over time.
The good news is that once you have planted your crocus bulbs, they will require very little care or attention (until the time comes to collect the fiddly harvest) and so are a really low-maintenance crop. Water when the weather is particularly warm and dry. If you wish you can also ensure good soil health with the addition of a good quality organic fertiliser once a year.
When the crocuses flower in the autumn, you can carefully detach the stigmas from each one very carefully with a pair of tweezers. Lay out the stigmas to dry on a piece of paper towel where they will not be knocked over or blown away. They should be dry within a few days and can then be stored in an airtight container and used sparingly in a wide range of different dishes