Black Locust Raised Beds

I was lucky enough to find a guy who was trying to pay off his home sawmill, and was willing to make me some black locust lumber for my raised beds  for a reasonable price. I paid $400 but that was enough to make all the raised beds I could reasonably care for, and it wouldn't have to be replaced in my lifetime. It also looked nice. Black locust lasts forever (meaning 50-100 years), even in direct contact with the earth, with no sealing necessary.
So if black locust grows in your area, see if you can find some local guy making lumber. One caveat: Make sure you cut/drill/modify it before it cures completely (6 months) because after that, it's like working with solid rock.

Because its a useful timber, has it been cut completely out of some areas?

My area has a lot of black locust. I've made raised beds, just by stacking small logs, log cabin style. I use it for fence posts, building posts, firewood and we eat the flowers.

Lumber made from it is beautiful, but I don't think it is considered useful timber, maybe because it grows too slowly, a very large black locust tree is very rare. I don't think it has been cut out of many areas because although it takes a very long time to get to any real size it grows back and spreads very quickly.

John C Daley wrote:Because its a useful timber, has it been cut completely out of some areas?

LOL!! no. Black locust is considered an invasive pest by zillions of people. It's impossible to kill, grows like a weed and resprouts aggressively when cut.
However, if people knew how useful it is and how relatively easy to control when planted and managed properly, it would be a very popular tree. It would take a long time to extol the virtues and uses of black locust but I will do it if anyone cares to know.
Just for starters, it's the fastest growing hardwood tree (several feet per year) that makes amazingly dense and long-burning firewood. It can be coppiced to make fence posts that you can bury directly in the ground with no fear of rot. The blossoms are very attractive to pollinators, beautiful and some people and animals eat them with delight. Build furniture from black locust and it's an heirloom likely to be around for centuries. The list is endless, really.

Mark Reed wrote: I don't think it is considered useful timber, maybe because it grows too slowly, a very large black locust tree is very rare.

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Actually, a young tree will grow up to 4 feet a year, and a mature tree will grow 2.5 feet a year (this is under good conditions). One of the things that keeps black locust from taking over is that it needs full sun so when it comes up against another woodland, it stops spreading. Even heavy undergrowth may stop a seeding from reaching sufficient sun to thrive.
If left alone, it will be like a normal tree but if it is cut, suckers will sprout all along the roots and create a small forest. Funny that trying to destroy it is the best way of propagating it.  In some areas where conditions are ideal, people are tearing out their hair trying to eradicate it.

I am planning to build a raised bed and I was looking into wood preservation methods like charring and water proofing with oil but Black Locust seams to require less hassle.

I've read that Black locust contains substances that inhibit the growth of other plants. Is this true for dead lumber as well and if so, isn' t it a bad choice for a raised bed application?

Zoltán Korbel wrote:I've read that Black locust contains substances that inhibit the growth of other plants. Is this true for dead lumber as well and if so, isn' t it a bad choice for a raised bed application?

I've used it in my garden for raised beds and posts for a long time. I use the leaves as mulch and have even used black locust saw dust in seed starting mix. I've ever seen any indication that it harms plants in any way.

Zoltán Korbel wrote: . . .

I've read that Black Locust contains substances that inhibit the growth of other plants. Is this true for dead lumber as well and if so, isn't it a bad choice for a raised bed application?

I've heard just the opposite. Black Locust is a nitrogen-fixer; it absorbs nitrogen from the atmosphere and emits it out its roots, so it actually helps plants around it grow better. It's like it provides a natural fertilizer--for free.

Perhaps you are thinking of Black Walnut, which emits Juglone. It can have a strong effect on some plants, but others are unaffected.