(07-01-2021, 01:05 AM)descodave Wrote: Hey, Terracore,
You think we could buy the top soil, add steer manure, & top with compost (from dump) (would that be “nutritious “ for the plants )? We know little, so appreciate the “scientific “ advice!
I don't have any scientific advice, just what we've learned from trial and error. Speaking from experience, I wouldn't buy the topsoil* on it's own (we tried that once, it's a big mistake). In order to get sufficient drainage we get the cinder soil and mix it with 1/2 compost. Steer manure should work if it's the kind I'm used to that is mixed with wood chips, but have never tried that here but would still be in addition to the cinders not in place of.
It would also help if we knew what you were trying to grow? For example, tomatoes suffer blossom end rot here if the soil isn't fortified with calcium. Most good tomato fertilizers have added calcium but it's something to think about- no two fertilizers are created equal whether its chemical or natural.
* Although they call it topsoil, I think the "top" was mined a long time ago. They are digging up the clay like soil underneath, which is why there is drainage and nutrient problems with the product. But it's not the lava / cinder only options that can be dug out of the ground in Puna, so it's "top soil".
Your original post said you wanted something "ready to plant in & won’t need fertilizer for a while". Unfortunately such a product is probably only available in a bag, possibly with a name like "Miracle Grow". Local stuff is going to take some mixing and work. We do occasionally buy bagged stuff for seed starting and small containers. When it's spent in 6 months or whatever it gets added to our compost pile and begins a new life.