Four <a href="//commons.wikimedia.org/wiki/Tomato" class="mw-redirect" title="Tomato">tomato</a> plants being cultivated using the <a href="https://en.wikipedia.org/wiki/ring_culture" class="extiw" title="en:ring culture">ring culture</a> method. The wooden frame is lined with waterproof plastic and filled with gravel and water. The pots have no bottom, so roots from the tomatoes penetrate into the watery gravel, whereas other roots remain in the soil to gain nutrients.
<a href="//commons.wikimedia.org/wiki/User:Jolly_Janner" title="User:Jolly Janner">Jolly Janner</a>
<span class="int-own-work" lang="en">Own work</span>