compost with black walnuts

Brewster, MN(Zone 4b)

My town has a wonderful compost pile near the dump but there are lots of black walnuts mixed in. How will this affect the compost?

Paxton, FL(Zone 8a)

I don't really know the answer to your question. But I do know that there is some kind of chemical in black walnuts that prohibits growth of a lot of plants. Therefore I wonder if compost with black walnuts in it would do the same?

Brewster, MN(Zone 4b)

Thanks Gingerlily. But that sure isn't what I was hoping to hear. We used about two truckloads of it on a steep hillside garden. The compost has held extremely well.The plants there are doing quite well for the most part. Maybe its because the drainage is so good and the bad chemical washes away. But it may also be affecting the flatter gardens adversely. Sure wish we'd have thought of this earlier.

Brighton, MO(Zone 6a)

How old was the compost? I've heard that the juglone breaks down pretty quickly.

Brewster, MN(Zone 4b)

The compost is 3 to 4 years old depending on where in the pile you dig. The shells don't seem at all broken down and I pick out as many as I can when I put it down as they aren't nice to step on with bare feet, either. You can get the compost by the pickup load for free and its such great stuff! So hoping your info is correct. It gives me hope!

Hahira, GA(Zone 8b)

Would it help to sift the walnut shells out? If they are still in pretty large pieces, it would get rid of them. Very labor intensive, but if you're concerned... might be worth it. Samantha

Paxton, FL(Zone 8a)

Well, now, what I was referring to is the black walnut tree inhibiting growth of some plants. In other words, certain plants don't grow well under or near a tree. Maybe the walnuts themselves don't have that same chemical. On the other hand, as old as your compost is, that might make a difference too. If some things are growing well in it, just pay attention to what doesn't grow well and don't use it for those plants.

Can't turn down free compost if it's good for some plants.

North Ridgeville, OH(Zone 5b)

Based on what I've found on various university web sites ...

http://www.google.com/search?q=juglone+air+%22break+down%22+site%3A.edu&hl=en&lr=&safe=off&as_qdr=all&ie=ISO-8859-1&sa=2

... the juglone in black walnut trees is highly concentrated in the roots, a little less in the bark & nuts, and even less in the leaves. Water doesn't do much to juglones, but oxygen breaks the compound down. The consensus seemed to approve of composting black walnut leaves, as long as the compost gets plenty of exposure to air for at least four weeks.

As for the nuts? I guess you could burn 'em. The juglones would be thoroughly oxidized, and you'd be left with charcoal & ashes.

Paxton, FL(Zone 8a)

That's good to know. Thanks, PuddlePirate.

North Ridgeville, OH(Zone 5b)

You're welcome!

So.App.Mtns., United States(Zone 5b)

There are some things that grow nicely in mulch with black walnut juglone in it... and I found out the hard way what dies in it.

Here's 2 links
http://web1.msue.msu.edu/msue/iac/greentip/blackwal.htm
http://ohioline.osu.edu/hyg-fact/1000/1148.html

Brewster, MN(Zone 4b)

Thank you darius for the links. I'm going to print up this info to have handy for others. If it ever quits snowing here I'll be ready for about 4 loads of compost to get spring off to a good start.

So.App.Mtns., United States(Zone 5b)

You are welcome. I had the links handy because I have written an article for DG on growing (or not) under black walnuts. It runs April 29.

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