Saffron may be the most expensive ingredient you'll ever eat -- in fact, it rivals gold in value by weight. Knowing this, it may be hard to believe that this valuable culinary commodity comes from a simple crocus flower. The saffron crocus is no more difficult than any other bulb to grow, but the fragile golden-red strands are labour-intensive to harvest. They must be hand-picked from the crocus on the day the flower opens, or else they rot and cannot be used. Saffron crocus bulbs should be planted in the autumn, which is also when they bloom.
Lay 5 cm (2 inches) of fine gravel or coarse sand in the bottom of a planter that is approximately 15 cm (6 inches) deep. Fill the container about 2.5 cm (1 inch) from the top with a rich, well-draining growing medium.
Dig a 5 to 7.5 cm (2 to 3 inch) hole in the soil and place the bulb in it, root-end down. Cover it with soil. Place the bulbs 7.5 cm (3 inches) apart if planting more than one crocus in the same container.
Place the planting container in a cold room at approximately 1.5 to 9 degrees C (35F to 48F), where it will receive four to six hours of sunlight a day. Water the bulbs lightly on alternate days. Stop all watering when the grass-like foliage begins to die down, usually around April.
Move the planter box to a warmer location to mimic the spring weather it would naturally experience outdoors. Temperatures of 10 to 21 degrees C (50F to 70F) are typical for most parts of the UK.
Watch for leaf growth from late summer to early autumn. Restart the every-other-day watering schedule.
Harvest the stigmas from the crocus the same day the flower opens. Cut open blooms from the stem and pluck out the strand of saffron with a pair of tweezers. Lay the strands on a paper towel to dry in a breeze-free area where they will not be disturbed. Place them in an airtight container when no moisture remains.
Trim back the spent foliage only when you are certain the plant is no longer blooming. Watch for new buds breaking through the soil within one to seven days after the first blossom. Sometimes a second flower will arise from the same plant.
Stop watering and move the planters back into the cold room for the dormant season.
Be patient when growing saffron crocuses. It takes a full year after planting before the first blossom appears.
Each crocus produces three strands of saffron. On average, it takes three strands per serving to flavour a dish. It would take 24 plants to supply a family of four with enough of the seasoning to enjoy around six saffron-spiced dishes a year.
Do not water saffron crocuses when they are in their dormant stage, from approximately April to September: The bulb will rot and die.
Purchase saffron crocus bulbs from a reputable supplier. The Autumn Meadow crocus is sometimes misleadingly referred to as "saffron crocus." Accept only Crocus sativus bulbs.