No set of signs proves poisoning, and waiting for certainty wastes the window when a vet can do the most. The working rule is simple: suspicious signs after access to the garden, combined with something chewed, dug up or missing, mean phone the vet immediately and let the clinic judge. Your job at home is observation, information gathering and a fast, calm journey, not treatment.
Signs that raise the alarm
Report vomiting that starts suddenly, drooling or foaming, pawing at the mouth, sudden diarrhoea, wobbling or unsteady walking, tremors or twitching, unusual drowsiness or the opposite, frantic agitation, pale or bright red gums, collapse, or a seizure. Any of these appearing shortly after garden time deserves an immediate call, and so does discovering chewed plant material, a dug-up bulb, a torn product packet or spilled pellets, even before signs appear. Do not wait to see whether signs develop after a known risky item: for many garden hazards, including certain plants, slug pellets, fertilisers, compost and some fungi, early advice changes what the vet can do. Equally, keep your report factual: say what you saw and when, rather than naming a suspected poison as if it were established.
The information the vet needs fast
Before you phone, gather four facts if you safely can. What: the plant, fungus or product involved, identified as precisely as possible, with a photo taken on your phone or the product packaging kept to hand. How much: estimate the missing amount, such as a handful of pellets or two bulbs, since quantity shapes urgency. When: the time window in which he was unsupervised in the garden, because elapsed time guides every decision. What he is doing now: the signs present, when they started, and his weight if you know it. Write these down before dialling, because stress garbles memory, and read them to the clinic in that order. Bring the packaging, or a sealed sample of the plant or vomited material if the vet asks for one, taking care not to handle suspect material with bare hands.
What never to do at home
Never make him vomit unless a vet specifically directs you to, in that call, for that substance. Inducing vomiting with household substances or by any improvised method can add burns, inhalation injury or a second emergency to the first, and for some substances vomiting is actively dangerous. Do not offer food, milk or water in quantity unless the vet advises it, and do not administer any human medicine or home remedy, however harmless it seems. Keep other pets away from the area and from any vomited material, and prevent him eating more while you wait: bring him indoors, on a lead in the garden only if he needs the toilet, under direct watch.
At the clinic and afterwards
Travel promptly, keep him warm and quiet, and watch him continuously during the drive if a second person can drive, since signs can escalate en route. Hand over your written notes, packaging and any samples, and mention every garden chemical used recently, including products applied by a gardener or neighbour, because residues on paws he licks count as exposure too. Afterwards, walk the garden with fresh eyes and remove or fence off what he reached: fallen fruit stones, bulbs brought to the surface by digging, compost he can raid, and any chemical stored at dog height. Ask the vet what to monitor over the following days, since some effects appear late, and note the answers beside the incident record. Afterwards, record the suspect plant and the advice given by the clinic inside KinsLe's Pet Passport, warning future sitters about that corner.