TC, the buckwheat shoots i grow get 4-6" but are very thin compares to sunflowers. They have a fresh greens flavor, with a tiny bit of tart/citrus. I grow them for 2 weeks to get more harvest weight, but they can be harvested at 10 days.
Adam, i have grown peas on cocomats, and in a peat moss, lime, and EWC mixture. You could add a small handful of compost for a biological inoculant, a small amount of greensand, dry kelp, or liquid kelp(what i use) for trace minerals, and some perlite, vermiculute, or small silica rock for extra aeration. I prefer hydroponic/soiless mixtures.
Are there any other threads about growning sprouts here?
(with photos' etc).
I think I would like to try some and to see how other have done it help with the learning curve.
Anything that you can eat the shoots of can provide good food so long as you can get a good stock of seeds to use. I've found a little shelf with some liner and capillary matting hanging into the water some where (or getting dripped on) can provide lots of shoots just using some coir and seed trays or pots though this won't provide any extra filtration, it will provide some nutritious shoots to eat.
Lots on youtube about sprouts! mason jars are the best. Since TCLynx told me about that I have bought several sprout items and the simplest is a mason jar with some mesh on the top. I cut gutter guard out in place of the circle and put it in the ring. it works well and it's easy- as I said... youtube!