I would like to know which edible plants can actually root from twigs and/or leaves put in water or a similar setup? Is it as simple as leaving them in water or do you need chemicals to induce rooting?
Theoretically you can induce most slips (of an asexually reproducing plant) to root in just water as long as the water is extremely aerated, the right temperature and the proper pH. Most plants that can reproduce asexually don't need nutrients from soil to start roots for a limited time. Once they slip/seed has used up its stored energy source it will need nutrients added to the water or to be transplanted to the soil.
These are the vegetables/fruits that I know of that can be grown asexually:
- Sweet Potatoes
- Jerusalem Artichokes
Note: You can start any plant hydroponically/aeroponically and then transplant it to soil later.
Sweet potato slips root readily in room temperature water near a light source. The slips are 8" cuttings from the growing tips, with all of the completely mature leaves removed. Tomatoes are also easy to root this way. Change the water and rinse the roots in room temperature water every other day for best results. Peppers take longer, but they will root. Fig trees root pretty well from ripe-wood and hardwood cuttings.