basic greenhouse solar power system advice

[Dee_aitch]

Hello,
I'm looking to set up a basic system to run an ultrasonic mister and an old pc fan in my greenhouse. Ideally I'd like to add a timer so the mister and fan come on when I want them to, rather than running all the time there is charge, so I'm aware I would need a battery to store power. What I'm wondering is whether it's feasible to set this up using something like a 20W 12v kit. Any advice or suggestions as to parts required gratefully received.
Thanks