I've been wanting to have a go at hydroponics for AGES but lack the space or a greenhouse to build a proper pumped setup. I have an East facing bedroom window and a large South facing office window which get a lot of sun.

I read about the Kratky method on the Hydro Reddit. It requires no pump for nutrient flow or air stone for oxygen supply to the roots. The basic theory with the Kratky method is that you provide the nutrients and as they're consumed the water level in the plant's container drops. In this air space the plant develops oxygen absorbing roots and below the water line it develops nutrient absorbing roots. Kratky's original paper can be found here.

A lot of the Kratky hydroponics setups I've seen on the internet use large plastic containers and set the plants in their net cups into the top of the lids. Being on a window sill I didn't want anything too large and so the obvious choice was glass jars. They're small, free and easy to obtain. I wasn't sure there'd be enough room for root growth but with little to lose but a few pennies worth of seeds and nutrient soloution, I thought why not try.

As a plus, the fact that the jars are clear makes this take on the Kratky method a great way to teach others (and myself) about it. Kids and adults both seem to get super excited when I take off the cardboard light covers and they see the roots.

This Instructable is meant as a place to leave photos I've taken of my experience so far. There's LOADS of material out there to read if you want to give it a go yourself. I'll update the pictures and descriptions in the future as I learn/try more.

Updated 22/06/2014: with photos of much bigger pepper plants, new pak choi and a second crop of french beans.