I use one usa measuring teaspoon Megacrop to a five gallon pail of water. Every watering, so far every thing seems to like it. Usually, the medium is high in perlite, but with layers of soil, peat, whatever. Then again, it might be just what is available in bags...i try to spot the bags that don't have bugs flying around them, argggh. Perlite is very hard to find in anything but the small bags (expensive, too) around these parts.