I'm sure I don't have to mention that we use the very same potting soil that you use here on YARDTALK, the one that's made of dirt and 27 other kinds of important planting matter. Now, these puffy nodules will remain yellow like this until just before they ripen, when the pressure of internal juices will cause them to burst, so when you see them turn a brilliant mauve you have about a half an hour to prepare the fruit and serve it. But don't dally or you'll need a mop.