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Are oak leaves poison to vegetable garden ? #435557

Asked November 29, 2017, 5:39 AM EST

Relative neighbors say oak leaves are poison to garden. They recently said they mulched and filled nine large bags of oak leaves and took to landfill. I said they could drop off with me since I mulch mainly with kitchen vegetable, coffee grounds, egg shells, etc. Neighbors said the oak leaves were poisonous to vegetable gardening which they do a lot of and to plants & flower gardens at our home. Please advise any caution with east coast oak tree leaves being used as mulch.

Sussex County New Jersey

Expert Response

The simple answer is no, oak leaves are not poisonous to a vegetable garden.

The longer answer is:
Oak leaves have high levels of tannins, which are somewhat acidic. If you were to eat copious amounts of the leaves or acorns directly, they might make you or an animal sick (see Illinois Poison Center info: http://illinoispoisoncenter.org/plant-list).

Oak leaves also tend to break down/decompose slowly. If you plan to use them as part of your garden mulch/compost, shred them so they break down more quickly. They'll likely be one of the last items to break down, and some gardeners use them as mulch for just that purpose.

If you can compost these leaves before you put them in your vegetable garden, you may have more success because they'll break down faster and offer more nutrients. Here is some basic information about composting, which mentions oak leaves: https://extension.illinois.edu/hortihints/0010a.html
Amara Rozgus Replied November 29, 2017, 10:57 AM EST

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