Healthy habits

摘要

A range of common problems on protected and outside nursery stock could be reduced or prevented by good nursery practice. When problems arise, growers assume there is a disease problem, but quite frequently there is some husbandry defect, which maycause the disease symptoms, or influence its incidence or severity. Watering is probably the most critical operation in nurseries, and is frequently the most neglected. Excessive watering during autumn and winter months often causes root asphyxiation andis a common cause of subsequent poor growth. This is most pronounced in outdoor containerised crops, especially if compost has slumped or compacted, or if the crop is standing on poorly drained beds or ground. In theory, this can be prevented in tunnelsand glasshouses. In practice, due to poor maintenance, faulty irrigation equipment or poor supervision/training of staff, under- or over-watering is common. With the majority of nursery stock now grown in specific peat- or bark-based composts, problemsof acidity, alkalinity and conductivity are rare. In protected crops, it is important to check the pH of irrigation water and adjust it if necessary. Acidification is often used for long-term, acid-loving shrubs to ensure healthy growth and to prevent deficiency symptoms. As well as ensuring good drainage, soil for border-grown shrubs should be analysed, or at least pH checked. Acidity is vital for Azalea, Camellia, Erica, Rhododendron and Calluna, but most other shrubs thrive in neutral or slightly alkaline soils.