Wow, Not knowing where you live, I can only give you a recipe: Coarse sand (not play sand); potting soil and compost (or screened topsoil if that's all you can get). My yard soil is sandy loam-ish, and I figure it's about two parts sand/three parts soil. You might want to add one part of organic amendments into that mix. If they sell a cactus mix that would be a start, but add more soil/organics to it. The numbers on the bag refer to N-P-K, nitrogen, phosphorus, potassium--in that order, always. The actual number represents the percentage of each ingredient in that particular mix. No it doesn't add up to 100 because the rest are inert ingredients to help evenly disperse the stuff. Each one (N,P,K,) boosts the growth of a different part of the plant: I.e., roots, leaves, flowers. But I forget which one does what. Right now, the roots will be damaged from the transplanting process, so they will be hard pressed to even take up water (but don't overwater!), let alone nutrients; and they may even burn if exposed to harsh fertilisers. If planting in a container, I wouldn't use something with such high numbers, not right off the bat. Look for single-digit numbers, or if you're making your own mix then the compost would take the place of chemical fertilisers and is a gentler, slow-release type of supplement for a stressed-out transplant. Pay attention to the watering requirements first, then worry about fertiliser later. I've not grown a Pawlonia, so someone who has can better advise how to care for it after it's established. A one-gallon pot for a tree sounds a little small, unless you're going for bonsai--but that's a different section.
(OK, fellow gardeners, how'd I do?)
Hi...I am new to the site and have recently purchased a Paulownia tree via the internet (another interesting story) ...the directions said to plant it in a 1 gal clay pot with sandy loam soil mix....I have no idea what this is...could not find it at Lowes or Home Depot...the garden shop I stopped at did not know what I was talking about and I don't seem to be able to get it via internet...could anyone tell me where I could purchase this? Remembering that it is for a pot not a yard
Adjunctively they have said I need a fertilizer 30 10 10 or 20 10 10...this alsois not available at any of the places I searched. The garden shop could not tell me what the numbers meant...
Thank you for any help you can give