What Hot/Cold means in a nutshell: Basically, certain flowers have a warm color (red, orange, yellow), which are hot, and cold (you know the drill).....yeah, so you bet a host on what flower it would be by giving them a certain amount of cash.
Then when they accepted the trade, you tell them what flower will pop up when they plant the seed, which shows up instantly. So if you said "Hot," and a hot type of flower shows up, you win double the money that you put into the bet.
And so on if you said the wrong flower, the host gets it, and also, if there's a rainbow flower (red, yellow, and blue), the host automatically wins unless you have some balls and predict that a ryb will show up. Usually, if you're right on that, you get 4-5 times the cash you put into the betting.
Easy way to make cash, IF you're hosting, but you can get lucky with betting as well, but it's always best to host, which is why people think it's a form of scamming, but if you find the right hosts that don't log out when you put a bet in, it CAN be addicting just like real life gambling.