Match the pack’s full name and PCS in DAFM’s label index. It links a 2026-to-date specimen for Roundup Flex Plus, PCS 07261. Check another formulation’s own wording separately.
What is the maximum wind speed for spraying Roundup?
For the Flex Plus specimen cited here, preserve the wording about windy conditions and drift damage. Do not manufacture a miles-per-hour or kilometres-per-hour limit from that sentence.
Locate the warnings and effects-of-weather sections in the matched label and read them together with the intended use. If a contractor or adviser quotes a number, ask where it comes from (the label, the sprayer's instructions or their own working rule) and write that source down next to the figure. If the product or equipment instructions disagree, settle that before you set the sprayer's wind limit.
Check direction as well as speed
Check wind speed and direction before deciding whether to spray.
On the field brief, mark what lies downwind: neighbouring crops, hedges, gardens, paths and houses. Mark drains, ditches, springs, wells and streams separately. Walk a contractor who does not know the holding through the map before the job, and point out boundaries that are hard to see from the cab. Ask which spots need a fresh check if the wind turns.
Gusty or changing wind belongs in the decision too. Write down what you actually observe at the field, at the time of the work, and do not replace an unwelcome field reading with a kinder figure from a distant forecast station. Agree beforehand what should make the operator stop and reassess, and note any material change when it happens rather than carrying the morning's reading through the whole day.
Use forecasts to plan, then assess the field
Use Met Éireann’s agricultural meteorology page to plan the job, then check the field itself. Do not spray if rain is forecast, and confirm there is a long enough window for the application.
If you take measurements, note the instrument, the units, where it was held and whether the figure is a single reading, an average or a forecast, and label remote readings as remote. Do not choose a sheltered corner just because it gives a lower number. If the sprayer shows weather data on its display, ask what the sensor measures before relying on it.
Keep nozzle choice within the label decision
Use low-drift nozzles such as air-induction and pre-orifice types with Roundup Flex Plus.
Give the person setting up the machine the exact nozzle data, pressure range, sprayer and boom width, and ask about output, coverage and drift together. If pressure, speed or nozzle type changes during preparation, redo the output calculation, and check for blocked, damaged or mismatched tips: a nozzle colour on an old order does not describe what is fitted now. A good weather window is not a reason to skip a known setup problem. Check the boom width against field boundaries and excluded areas so the operator knows exactly which part is to be sprayed. Details are in the sprayer-nozzle guide.
Rain, weed condition and hedgerows on the Flex Plus label
The Roundup Flex Plus label also requires a period without rain of at least 6 hours, preferably 24 hours, after application. Do not spray weeds whose growth is impaired by drought, high temperatures, dust cover, flooding or frost, or poor control may result. Take extreme care to avoid drift, particularly near or alongside hedgerows.
A dry forecast does not settle the wind question, and calm wind does not settle the rain or weed-condition questions: check each separately. The rain and herbicide guide covers the rain side. If you switch to another product, compare its own label again, because a familiar brand name does not guarantee the same weather wording. Also check that the crop or situation on the label matches the real job (stubble, grassland, orchard) and that the name and PCS number match the container.
Drift near hedgerows, non-crop plants and water
The Roundup Flex Plus label opens its warnings with drift: extreme care must be taken to avoid spray drift onto non-crop plants outside the target area. Do not mix, store or apply the product in galvanised or unlined steel containers or spray tanks, and do not leave spray mixtures in the tank for long periods.
Keep your spray records in one place. Free to start.
The professional user must know where all nearby watercourses are, including drains, wells and springs, and carry out handling well away from them. If the product label specifies an aquatic buffer zone, comply with it during spraying. Pesticide safeguard zones, where no use or storage of pesticides is permitted, cover groundwater abstraction points such as wells and boreholes.
Label timing after the spray
After application, keep stock out of treated areas for at least 5 days and delay lime, fertiliser, farmyard manure and other pesticides until 5 days after spraying. Disperse or bury large concentrations of decaying foliage, stolons, roots or rhizomes by thorough cultivation before drilling the next crop.
Weeds must be actively growing with green leaves at the correct growth stage. Annual grasses and broad-leaved weeds should have at least 5 cm of leaf or two expanded true leaves, perennial broad-leaved weeds are most susceptible around flowering, and bracken should be treated after the frond tips unfurl. Do not treat survivors with another dose of glyphosate; destroy them by other techniques such as destructive cultivation.
Who may spray, and where a risk assessment is needed
Roundup Flex Plus is a soluble concentrate with 500 g/L glyphosate, present as the potassium salt, for professional use only. It is toxic to aquatic life with long lasting effects, so wear protective gloves, clothing and eye or face protection.
Anyone who applies a product designated for professional use must be trained and registered as a professional user with DAFM, and must show a PU number to buy it. Use a pesticide advisor for integrated pest management and application advice. A closed spray period, during which use is not permitted, is specified on the label of some products, for example those containing MCPA.
Risk assessment records showing the need for pesticide use must be kept for applications in areas used by the public or vulnerable groups, such as public parks and gardens, hospitals, schools and playgrounds, and in Special Protected Areas and Special Areas of Conservation. Those records are required for applications in these specific areas.
Horsetails are not controlled to an acceptable level by this product, so repeat treatment will be necessary. The label also warns of a risk of weed resistance and asks for a strategy that integrates herbicides with cultural control measures.
What the product does to what it hits
Roundup Flex Plus is a non-selective, foliage-acting herbicide with broad-spectrum activity. Foliage takes it up and carries it to underground roots, rhizomes and stolons.
Where ragwort is present, consult the Code of Practice on how to prevent its spread. Ragwort sprayed with this herbicide is more palatable and contains higher levels of toxins, so exclude animals from treated areas until the ragwort has completely recovered or died, and do not include treated ragwort in hay or silage.
Records and clean-up
After spraying, clean the sprayer inside and out while still in the field, and spray the washings onto a suitable area of the same crop without exceeding the maximum allowed dose. Never fill or wash a sprayer on concrete or sealed surfaces where spillage can reach drains or watercourses.
When adding products, the user must wear PPE: half fill the sprayer with clean water, agitate and add products as the label directs. Take the utmost care to avoid spills and never leave a sprayer unattended; a bund or lip around the filling area is recommended. Triple rinse empty containers into the sprayer and recycle them. Store all products on the farm in a secure, bunded and clearly identified chemical store.
Equipment and calibration
The Sustainable Use of Pesticides Directive 2009/128/EC of 21 October 2009 sets the framework for Community action. S.I. No. 155 of 2012 gives it effect by regulating the training and registration of pesticide advisors, distributors, equipment inspectors and users. Never fill a sprayer directly from a watercourse: a single foil cap can contaminate a small stream for 30 km.
Ensure the sprayer is within its test-certificate requirements before use and calibrate it regularly; keep a record of calibrations. Select the nozzle for spray coverage while minimising drift.
Keep a record for each job: product, field, area actually treated, and the weather you observed. If work stops partway, write down the area finished and the reason, so a whole-field plan does not turn into a whole-field record. Keep postponement instructions and cancelled jobs in the planning history. With a contractor, agree who records conditions and who receives the notes.
Next step
Read the matched label and assess wind at the field before confirming the nozzle configuration.