This will enable some adjustments to the fertiliser program and provide information on nutrients that are deficient or toxic. Some of the suggested nutrients in the programs in this publication may be deleted or reduced, if it is obvious that they are sufficiently high in the irrigation water and soil, including sources from compost and fertilisers from previous cropping. Do not apply excess fertilisers, because nitrogen, phosphorus and potassium are easily washed through sandy soils by rainfall and irrigation. This may lead to groundwater pollution in rivers and estuaries. There have been no trials to obtain information on the watering requirements of leeks.
Growers use overhead irrigation systems and keep the plants well watered.
Water below 1000 ppm in total soluble salts is preferred to produce good yields and quality. There are no major problems with soil borne diseases or nematodes, so metham sodium is not normally used as a soil fumigant before planting. Bacterial soft rot is sometimes a problem in the autumn and cooler months, especially in the leaves and shanks below ground. Few problems are experienced with pests in leeks. Onion seedling maggot, two spotted mite and grubs can occasionally be a problem.