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WNC Usa

I did not plant a garden last year and did some spraying of thistles. However I noticed several seedling black walnuts sprouting up in the garden.

I sprayed them with Roundup as I was using that on the thistles already.

My question is, even after killing back the seedlings, will there be juglone in the soil?

Thanks

2/17/2014 9:49:15 AM

Whitehall Montana

I have sorta the same problem here as my patch is located next to a black walnut tree.Without realizing the patch was taking on the walnut leaves,I had them tilled in with other amendments,but had no problems last year.

2/17/2014 10:14:35 AM

Anamosa, IA BPIowegian@aol.com

I have hundreds of walnuts on my acreage, from seedlings to 18" diameter. Some are fairly close to my garden. I don't think that the leaves will have much juglone in them, as my gardens get leaves blowing on them all the time with no problems. I think you will have more problems if you get the roots from large trees growing into the garden. The hulls on the nuts have lots of harsh stuff in them. One time we put some nuts on the driveway and drove over them to loosen the hulls. We put them into a chicken wire basket and used the hose to wash the hulls off in the grass. It drove the night crawlers out of the ground like crazy, but it didn't hurt the grass.

2/17/2014 11:43:42 AM

WNC Usa

Thanks

I too have some walnut trees. That is where the walnuts came from

2/17/2014 9:36:48 PM

Bethlehem CT

In most cases, the damage caused by black walnuts to other plants is a combination of the presence of juglone in the soil, and the competition for light, water and nutrients.

However, juglone can cause severe damage and even kill solanaceous crops (tomatoes, potatoes, peppers and eggplant). Fortunately, not all plants are susceptive to the chemical. Most trees, vines, shrubs, annuals, perennials, corn, beans, onions, beets and carrots are tolerant of juglone.

Gardeners who have large walnut trees near their vegetable gardens should consider an alternate site. The greatest concentration of juglone in the soil exists within the dripline of the trees. The dripline is the area between the trunk of the tree and the end of the branches. The toxic zone from a mature tree occurs on average in a 50-foot radius from the trunk. Avoid planting your garden in these areas to protect your garden from damage.

Walnut leaves can be composted because the juglone toxin breaks down when exposed to air, water and bacteria. The toxic effect can be degraded in two to four weeks. In the soil, breakdown may take up to two months after the living walnut tree has been removed. Mulch or woodchips from black walnut are not recommended for plants sensitive to juglone. However, composting the woodchips for a minimum of six months allows the chemical to break down to a safe level even for plants sensitive to juglone.

2/18/2014 9:09:59 AM

Bethlehem CT

The above info was cut and pasted from this website. http://www.extension.iastate.edu/news/2005/jul/070701.htm

In my personal experience Juglone toxicity is rarely a problem. I have used hickory and walnut leaves on my garden for years. Soil biology is a wonderful thing. What may be toxic to some things is food for other things.

2/18/2014 9:17:22 AM

Johnston, Iowa

The article Big Moon posted is a good one. The allelopathy effect of walnut can be a game-ender in some areas. I grew up in a house where our neighbor had one of these trees, and its negative effect on our garden became worse as the tree grew. Continue to Round-Up those baby walnut trees with extreme prejudice!!!

2/18/2014 12:25:30 PM