Saffron (Crocus sativus)

How well established is this crop?

This is a very new crop to the Otago region. The plants should grow but information on markets, commercial returns, current growers, and any form of regional research may be difficult to find.

Background

The use of Saffron as a spice is though to have originated in the eastern Mediterranean nearly 4000 years ago. Since that time it has maintained its position as the world’s most expensive spice worth more than its weight in gold.

Saffron comes from the flowers of the autumn crocus. This small corm flowers in the autumn, has foliage in the winter that dies off in the spring and the corm goes through summer dormant.

The actual spice itself is the three bright red stigmas that are the male parts of the flower. These are removed, dried and used to add subtle flavour and colour to dishes. The flowers coming from the crocus are actually sterile meaning the only way to reproduce the corms is to use vegetative means. They readily bulk up and small new corms are easy to divide from the parent.

Climate

As Saffron originates in the Mediterranean it prefers a warm dry climate. However if the soil conditions are correct it can be grown successfully in other areas.

Winter Chilling and Frosts

Saffron has been grown successfully in a range of locations throughout Central Otago. It does not seem susceptible to frosts during the winter and flowers successfully every year.

Rainfall and Irrigation

Water is essential during the establishment phase of a Saffron block. It is also necessary when the crop is developing its flower heads in the period leading up to harvest in the autumn.

Wind

Even though Saffron is a low growing plant, shelter from the wind is advisable. It will reduce the amount of damage to the plants and subsequent disease problems. Be careful with design to allow the plants to get the maximum amount of sunshine during the growing season.

A good rule of thumb when designing shelter is to multiply the final height of the shelter by 5. Use that measurement as the distance you position your shelters apart. For example, when using shelter trees that are 10m high you will need shelters 10m x 5 = every 50m.

Soil

The key physical requirement of the soil for Saffron growing is a free draining root zone. This will ensure the roots and corm is not wet which can lead to fungal diseases. To further reduce the chances of this, raised beds are often used.

Fertility

Saffron corms do not need high levels of fertility to grow well. The only part of the plant being taken away at harvest is a small flower so nutrient turnover is not high. Small annual applications of fertiliser will boost the crop. Slow release products applied in the spring are the best.

Weed Control

Weed control is essential to successfully grow this crop. Hand weeding is time consuming and expensive. As the corms are dormant during the summer, herbicide may be able to be used. This will make sure the crop goes into the autumn flowering period relatively clean.

Varieties

There is only one variety of autumn flowering Saffron corm. The flowers are easily recognisable due to the large size of the stigmas (up to 3cm long).

Pests and Diseases

Saffron suffer a few fungal diseases but if the plants are grown on raised beds or in free draining soil the effect of these will be reduced. The other main pest is rabbits, they dig up corms and feed on foliage. Nettings around the blocks is recommended.

Layout

Saffron beds tend to be planted about 1m wide with up to 50 corms per metre. Spacing beds 30-50cm apart will allow for foot access between them. Planting densities higher than 50 corms/m2, will mean the beds have to be dug up, divided and replanted earlier. At 50 corms/m2 this will only need to happen after 4 growing and harvesting seasons.

General Management

Corms tend to be planted out in there dormant period in summer. Small corms less than 1.5cm diameter should be placed aside and planted in a nursery bed to increase in size. In general the larger the corm the greater the number of flowers it will produce. Corms should be placed about 5-10cm deep in the soil and watered in well. Some growers use a mulch of sawdust to cut down on the requirements for hand weeding or the use of herbicides. Mulch is also a useful way of maintaining soil moisture and would be beneficial to growers in Central Otago.

Weed control is the main activity outside the harvest period. After about 4 seasons it is common for the beds start to get to crowded and the production drops. This is the time to lift the corms and divide to plant more area.

Harvest

Harvesting Saffron is an incredibly time consuming activity. Flower must be plucked from the corms before they open. This is generally done in the morning or evening when there is no moisture on the flowers. The flowers are then taken for processing where they are opened by hand and the stigmas removed for drying. If this is not done immediately after harvest in the field the flowers should be chilled.

A small domestic dehydrator set to 30°C for 24 hours usually will suffice for drying batches of stigmas. Any larger batches are unlikely due to the workload required even for this amount. Once dried the Saffron must be carefully handled so it does not break. It is usually packaged in an airtight storage container for sale.

Equipment

After preparing the ground and planting most work on a Saffron block is done by hand. This means requirements for a spray pack and some kneepads. At harvest a dehydrator is needed to dry the crop.

Returns

Saffron is being grown successfully in a number of locations, from Central Otago through to the Taieri Plains. Yields vary depending on location and grower experience. Research done at Redbank near Clyde in the 90s showed yields varying between 3-5gm of dried saffron per m2 of bed.

Although some small sales have been completed returning $20/gram to the grower, bulk sales to commercial entities in the overseas markets are likely to be $6-8/gram. Saffron grown in Kashmir is available for as little as $2/gram. Quality lines will always attract higher prices.

Contacts

A Saffron growers Association has been set up. The contact people for this group are Megan Huffadine and Maurice Watson, Cromwell.