Valerian (Valerian officinalis)

How well established is this crop?

This crop is relatively new. It has been grown here commercially for approximately 5 years. Commercial returns, current growers and some level of regional based research may be available to help those new to this industry.

Background

Valerian officinalis has been widely used in Europe as a sedative for many years. The active ingredient is mainly in the roots of the plant and is known simply as Valerian. It is known to reduce the effects of insomnia and act as an antidepressant. Valerian can be taken as a crushed up root or in capsules. Valerian oil is also available and is made by steam distilling the roots.

Valerian is a perennial and grows from winter dormancy to over 2m tall, flowers then dies off again. If grown for cropping the plant can be treated as an annual. Although a native to eastern and central Europe, Valerian is now grown worldwide after being taken by immigrants as a medicinal plant.

Climate

Valerian grows in a wide range of climates and soil types all over the world. It is the type of plant that will grow nearly anywhere but like most cropped plants, a good soil type and water will ensure quality harvests.

Winter Chilling and Frosts

Valerian will grow all over Otago and tolerates frosts as long as they are not out of season events as this can damage the foliage.

Rainfall and Irrigation

Valerian does best if the roots are kept moist with a combination of rainfall and irrigation. Overhead watering is the best method for this crop as it is grown on a broad acre scale.

Wind

Because Valerian is grown in a paddock situation there is little benefit from wind protection.

Soil

The key physical requirement of the soil for valerian growing is a free draining root zone with a very friable soil. You harvest the roots so a clay soil type will mean breakages and a reduced crop.

Fertility

To get a good crop from Valerian, soil fertility needs to be high. Applications of a general NPK type fertiliser, based on soil test results is recommended before planting, with a follow up application of nitrogen based fertiliser when the plants are actively growing.

Weed Control

Starting with a clean seedbed is the key to success with this crop. Valerian is a strong grower and will out-compete most weeds.

Varieties

Although there are a number of valerian species, only Valerian officinalis has medicinal properties.

Pests and Diseases

Few insects live on valerian plants. Fungal diseases, notably Sclerotinia and
Phoma are the main problems. Phoma mainly infects the plants in the spring and is caused by warm moist conditions. Sclerotinia is more prevalent in the autumn as the plants start to die off. Fungicides can be used for both these diseases.

Rabbits can be a nuisance as they like to dig around the bottom of the plants and expose the roots. However, they have not been observed eating the actual plant.

Layout

Using transplanted plugs seems to be the best way to get a valerian crop established. Direct seeding has been less effective. Ideal spacing seems to be rows 40-50cm apart and plants within the rows 20-30cm apart. Plugs are more expensive so some work on the economic of the two systems may be needed. The key thing is to make sure you are planting into clean soil free of weeds. Pre-planting herbicides are the best way to guarantee this.

General Management

After crop establishment little is needed apart from water and watching for fungal diseases.

Harvest

Harvesting tends to be done by machinery as this crop tends to be grown on a large scale.

Valerian is grown as an annual crop. In the autumn a foliage cutter is used to slice off the tops. A root crop lifter such as a potato digger then goes through the filed to a depth of 30cm lifting the roots to the surface. They are then shaken and washed.

Roots are dried down to approximately 25% of there fresh weight using forced air drying at no more than 40C. This ensures the active ingredients are not broken down. Once dry they are packed in barrels for sale or further processed.

Equipment

After preparing the ground and planting most work on a valerian block will be done mechanically. This means requirements for a tractor, spray unit, harvest machinery, bins etc.

Returns

It is very difficult to estimate returns for New Zealand grown valerian due to the fact that it is a worldwide traded commodity. Finding niche markets will be the key to success.

Contacts

Crop and Food Research Ltd Broadsheet # 34: www.crop.cri.nz