Monday, 3 March 2014

Timing advice for SmartGrass

Enhancing the growth rate of grassland in the spring so that stock turnout or cutting for silage can be brought forward would be a key objective for many grassland farmers. SmartGrass, a patented formulation of gibberellic acid, has been proven to enhance the growth rate of grass in the early spring, but its spray window is fast approaching and it is important to apply it at the right time in order to get the maximum benefit.


Stewart Woodhead, Technical Manager for Interfarm, explains that the spray window for SmartGrass is usually between mid-March to mid-April, depending on geography and weather patterns.  “SmartGrass is applied at 20 g/ha as a conventional spray to grass leys for stock grazing or silage. It works on all grass species and both grass leys for stock grazing or silage are suitable for treatment. But it must be applied at the right time, which is at the start of active spring growth, when grass is between 10 and 15 cms. Air temperatures should be warming and likely to remain warm for 7 days.”

He emphasises that the sward must be of good quality, good fertility and adequate moisture in order to support the extra growth that SmartGrass will bring.  “SmartGrass should not be used too late or if crops are suffering from saturated soils, pests or diseases or other stress factors. It is not a miracle cure. Response from a good quality sward will always be far higher than from a poorer sward. Nor is it a substitute for fertiliser – swards should have adequate nutrient supply to support the extra growth anticipated.”

Stewart explains that SmartGrass accelerates the growth rate of grassland for about a 6 week period.  “Gibberellic acid increases plant cell expansion and numbers, resulting in leaf and stem elongation. What you see is taller, lusher grass and increased dry matter per hectare, enabling earlier use of grassland for grazing or for cutting for hay or silage production. By bringing timing of the 1st cut forward, your second cut can also be earlier, bringing the whole season forward and maximising yield and quality during the spring peak in grass growth.”

The use of SmartGrass also helps with planning feedstuffs at turnout. Increased pasture production reduces the need for supplementary feeding, which can be expensive, says Stewart.  “Treated grass has the same nutritional qualities as untreated grass.”

He warns that once rapid growth has started, grass produces enough of its own gibberellins and the opportunity to advance growth further will have passed. First year leys are naturally vigorous and may not give the best response.


Developed by Valent BioSciences Corporation, part of Sumitomo Chemical Company, SmartGrass is already used successfully in Australia, New Zealand, the USA and Chile. “Its UK registration follows three years development work across UK and relevant European countries,” says Stewart Woodhead.