Vegetables in the 90's - what are the alternatives?

ADAS

VEGETABLES IN THE 90's - WHAT ARE THE ALTERNATIVES?

Garlic (Allium sativum family Amaryllidacae)

Imports have risen to about £2.6 M representing about 2,500 t. The main sources of supply are France, Italy, Spain and Argentina. Smaller quantities arrive from all over the world including China and the USA. By far the largest area in Europe is grown in Spain. The crop is very susceptible to bruising and mechanical damage. Most crops are still produced using hand labour. Attempts to mechanise operations have not been too successful because of bruising and the difficulty of "dressing" the bulbs for market. This limits the scale of production but keeps the market price high.

The crop grows quite satisfactorily in England. But if a yield of 10 t/ha is achieved the potential area required to satisfy the home demand for the fresh market could be as little as 250 ha. The possibilities for processing, (including medicinal) or export may be worth investigation.

Each bulb consists of 7 - 12 cloves. Varieties vary in the numbers, size and ease of splitting down to cloves from bulbs. It is well known that larger cloves tend to produce larger bulbs. In order to form proper bulbs the plants require a cold period. There are basically two types. Firstly; broad leafed, large clove, short dormancy, early maturing but not such good keeping quality. Secondly; narrow leafed, smaller cloves, long dormancy, later maturing, longer keeping.

Culture

On most workable, well-drained soils planting should take place in the autumn, mid October to end November. On heavier soils spring planting in February of the second type of cloves can be successful.

The main vegetative growth period is late March to May. Dry springs can therefore reduce yields considerably particularly on light soils, unless irrigation is available. Bulbs are formed from the end of May and through June. The earliest varieties can be harvested from early July. Most varieties should be harvested by mid August.

Pests and Diseases

It is important to hot water treat the cloves at 46ºC for 2 hours before planting against stem eelworm.Virtually all stocks have one or more viruses; onion yellow and garlic mosaic virus being the two that reduce vigour and yield the most. Other pests and diseases are similar or the same as bulb onions, so it is important to bear this in mind when planning cropping programmes.

Weed Control

Weed control with herbicides can be effective and observations have shown that generally the same materials can be used as on bulb onions.

Work at Efford EHS is currently concerned with -

Spacing trials.
Variety trial, including autumn and spring planting.
Nitrogen nutrition trial

Spacing

The spacing trial, has been autumn planted, either direct or into 38 mm peat blocks subsequently planted out in early spring. Results show that yield increases with density but at higher density the bulbs are smaller. After two years of trials about 30 bulbs/m² seem to be the optimum density (variety Fructidor). This confirms work from other countries.

Varieties

The variety observation and main trials have included up to 15 stocks and varieties. After three years the main conclusions are -

Most are winter hardy.
On Efford soil (which is water retentive but will slump and compact) there is little difference between yields of cloves planted in autumn or spring. While autumn plantings tend to be heavier, spring plantings tend to be of better quality.
Larger cloves give heavier yields than smaller cloves.
Once dressed in the autumn most varieties are acceptable on the market.
The bulbs of some varieties split into cloves much easier than others. This may be an important consideration regarding commercial acceptability.
All the stocks at Efford have virus. Samples of the main varieties have been sent to NVRS with the objective of growing virus free stock.

Observations have commenced this year on how well the varieties store.

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