Foliar Fertiliser: Your Questions Answered by New Zealand Soil Scientist Dr Gordon Rajendram
Q: Why is liquid foliar fertiliser especially important as we head into colder months? As soil temperatures drop, pasture growth slows. At around 5 to 6 degrees, grass can stop growing. The primary reason is reduced microbial activity. In warmer conditions, soil microbes convert nutrients into plant-available forms. In the cold, this slows significantly. Foliar fertiliser works differently. It delivers nutrients directly into the plant through the leaf, bypassing the soil. When applied, nutrients can enter the plant and roots within an hour, keeping growth systems active when soils are not. Q: How does foliar feeding work? Foliar fertiliser is applied to the leaf and absorbed directly into plant tissue. This allows rapid uptake and immediate use and growth. Farmers understand this. Herbicides such as Roundup are applied as foliar sprays to kill weeds quickly, the same principle applies here. Just as it’s possible to get herbicide into a plant rapidly using foliar to kill and eradicate plants quickly, you can just as effectively deliver nutrition for plant growth. Foliar is a more efficient pathway, especially in challenging conditions. Q: What have trials shown about its effectiveness? Trials in New Zealand, including Canterbury, show clear increases in pasture growth when foliar fertiliser is used in cooler conditions. International research supports this finding. Studies show yield increases of 15 to 19 percent under stress conditions, particularly when soil performance is limited. This has been demonstrated in the field with farmers seeing a response within days and maximised within 3 to 4 weeks. In addition, foliar application is more uniform and provides nutrition to plants evenly. Q: How does New Zealand’s foliar fertiliser use compare internationally? Overseas, foliar fertiliser is no longer niche. It is standard practice across many farming systems, from broadacre crops like wheat and maize to intensive production. In high-performing systems, multiple foliar applications are used through the season to maximise results. In comparison, New Zealand systems still rely heavily on soil-applied fertiliser, often around 70 kilograms of urea (36 kg N) per hectare in a single application, with less focus on foliar strategies. Q: Why is foliar more widely adopted overseas? The main driver is nutrient use efficiency (NUE). Overseas farmers focus on maximising return from every unit of nutrient. Foliar fertiliser allows faster response to plant demand, quicker correction of deficiencies, and better performance when soil conditions are limiting. In many cases, farmers use half to a quarter of the usual fertiliser and still achieve the same response. Q: Is foliar fertiliser a replacement for traditional fertiliser? No. The most effective systems use both. Soil fertiliser builds soil foundation, while foliar fertiliser fine-tunes performance by filling in the gaps. It is about using the right tool at the right time. Q: What is the key takeaway for farmers? As soils cool and biology slows, relying on soil fertiliser alone limits potential. Foliar fertiliser provides a direct line into the plant when other conditions are not favourable. Consequently, for growth maintenance and improved efficiency, foliar feeding can be a game-changer. Contact Dr Gordon Rajendram 021 466 077 | rajendram@xtra.co.nz www.gordonrajendramsoilscientist.co.nz Contact MediaPA Phillip Quay MediaPA 027 458 7724 phillip@mediapa.co.nz









