That's easy. Remove any remaining roots and loosen up the soil mix thoroughly. Then add MM-Plantfood.The box comes with a cardboard scoop with measurements indicated on the side. Fill it to the 50 mark (roughly 30 grams or 3 full tablespoons). Sprinkle it over the empty square patch and mix it all together with the soil mix. The Planty app reminds you when to do this That's it. Then you can sow again.Extra nutrients for large, hungry plants: 30 ml/per square patchSummer vegetables like tomatoes, zucchinis, and cucumbers use up more nutrients than other vegetables. They also stay in the same square patch for a long time. So, when you plant the summer vegetables in the patch, add 30 ml (2 full tablespoons) of our nutrients. Give them another 30 ml 2 months later.