A lot would depend on the genus and species you wish to plant Luis. There are succulent growers on this forum who know a lot more than I do about them but I suggest that you use a little of the worm casings (I presume that this is what I know as worm casts), mixed with a lot of the sand and some of the forest product. Many succulents and also woodland bulbs will grow happily in a humus rich mix but control of the moisture levels in the compost can become a problem. For for most winter growing bulbs you would be better to make your mix of around 50% sand, 30% worm casings and 20% forest compost. then add a small amount of the guano for food. However guano is not a fertiliser I would ever have thought of using for either succulents or bulbs. You would be better to water with weak solution of tomato feed when the bulbs are in leaf. I have a large bag of Kellogg's mix > >which is organic forest products (not too chunky) along with worm > >casings and guano. I also have a large bag of horticultural sand. > >Since most of my bulbs will be planted in the fall (due to where I > >live), I am concentrating on succulents and other plants right > >now. I will have many bulb questions in the fall! What ratio of the > >above ingredients should I use for your average bulb in a pot? Your > >average succulent? > >