why do my veg plants bolt and go too seed very quickly

Mine did that too.I was told by some experienced gardeners here that it was because we had put in manure before planting.I thought this was odd because I thought that manure was very good for the garden.I was wondering if it was because of our hot and cold weather pattern here lately.

It's the conditions they are growing in, on long summer days brassicas will flower and go to seed, cauliflowers are already flowering, in the spring and autumn they grow slowly to make more green parts to the plants with more moisture and fertiliser being absorbed slowly.

Could be the manure answer - turns out we'd manure'd our 1st ever raised bed b4 finding out that brassicas aren't happy in the 1st growing season after enriching the soil.