I have just built a little greenhouse in Christchurch and I want to be able to extend growing season by using plant lights and some kind of solar or passive heating to slightly raise night temperature in the middle of winter.  I am a complete dummy when it comes to electricity ( I had 3 different teachers in sixth form physics who all taught me mechanics but ran out of time for electricity) so I am confused with all the discussions on volts , amps, watts  converters, types of plugs etc when I look at products available. Particularly when I look at say aliexpress or other overseas sites for grow lights I don’t know what they are compatible with.

I thought if I get some kind of energy store and solar panels like a camping set up it could also double as a back up for lights and cellphone charging for the house in a power cut. I like the option of being able to top up with mains power in the gloomiest part of winter if it isn’t charging enough with solar so I need to be able to move it from the greenhouse to the house for overnight charging (or run a lead to it?). Or so I can bring it inside in power cut to use in the house. 

lighting seems feasible with LED nights not using much power  but what is the best way to keep a greenhouse a little warmer over night in winter?  I just want to have the ability to say grow tomatoes in autumn and spring and winter over plants normally found further north like tamarillo citrus, maybe banana ? . Here we get frosty nights frequently in winter and I keep killing things!

It has concrete pad floor so I’m thinking adding a layer of insulation then paving over it? Maybe water barrels painted black to absorb sun light and radiate back at night? Or enough solar energy to run a low wattage panel heater through the coldest hours of the night? or some way of keeping water barrels slightly warm over night?  Or is that too much to expect?

I really need a list of products I can hook together that will work together as I am totally lost when I start reading the technical posts on solar.

Thanks!