I've never sworn on the BL skills and haven't taken BLV myself yet (BLV is easily the most time consuming skill so unless you take it early, it will take a ridiculous time to learn - my skill tree says it would take me 17+ days). Gardening vs. Soil Appreciation depends on which you harvest more, trees or your garden. If you really use Tinkering enough to merit taking it, then sure, learn it.