It would be helpful if you shared your general location with us. I can tell you that it's not dangerous, though. That's the easy part....there are a mere handful of species that are considered harmful and thousands that aren't.

There are so few that you can very easily do a search on 'venomous spiders in (your region) '. Learning to recognize a couple of spiders won't be so overwhelming.

Let me know your location and I'll be happy to help. In the meantime, though this image isn't particularly helpful in leading to an ID, I can say with certainty that it's not something to fear.

Spiders should be welcomed in the garden.

ANY spider in a garden is helpful! There are only two genera of spiders in the US which are considered to possess "medically significant" venom, that is, venom capable of causing serious negative effects in humans who manage to be bitten, and those two genera are Latrodactus(Widow spiders) and Loxosceles(Recluse or "fiddleback" spiders). Learn to recognize the distinctive features of each and whether they are even found in your area. NO spider is a threat to humans unless pinned, as all will avoid contact with us if possible. Bites occur when the spider is unable to escape. I can't see enough of this spider in the photo to make a definitive ID, but I CAN say, without a doubt, that it is neither a Latrodactus nor a Loxosceles, so it poses no risk whatsoever.