First time I've grown ruhbarb, when do I pick it?.

Green rhubarb isn't poisonous, only the leaves are.
Put a bucket with no bottom in it, over the top to exclude the sunlight. This will keep it red.
Don't pull rhubarb if the leaves are bigger than your hand.
Sugar can be added to your own particular taste.

Tonto, I never add water to ruhbarb when I cook it. I wash it remove all the green bits, then cut it in 3 cm pieces across. Put it in a glass dish with enough room over the ruhbarb. Cover with plastic film. For say 4 sticks, cook about 3-4mins on high in the microwave. Let it cool down a bit, then add sugar and stir through. I would say a tablespoon per stalk. The sugar will make it look runny, but when cooled off completely and stored in the fridge, you'll find it thickens a bit. Never add water, as that spoils it. The microwave method keeps all vitamins in and the colour right. Doctor Bob is right, green stalks are ok, but they'll be ever so sour.

Hiho Silver away, ride into tomorrow 2day -
ahem, yes er, rhubarb: my German neighbour swore by not eating it after mid-June, tho as Bob says, i think it's only the leaves which can harm - some acid or other I've heard from scientist husband.

silly me - you're on the other side of the world from Yurp by the look of it. So maybe for June, read December? Help!
Or just ignore my advice altogether.
I could tell you how to make crumble tho, if that compensates for muddying the waters?

Rhubarb crumble I love that.
You gave me a giggle there Evelyn, by the way you can always borrow my glasses now I don't need them anymore. Lol (Sorry only joking)

I stop pulling stems about mid summer as well so the plant can build up strength for the following year. If it ever gets to throw up a flower stem, you know it's growing VERY strongly so you can pull stems for longer without weakening it too much

green rhubarb, could be a green variety, that is only pink at the start of growth. as the plant ages some of the stems get 'stringier' but still edible.