For 10-12 years we've been tilling in lots of oak leaves in fall for fertilizer and heard recently this may not be a good idea. We have established a seed bed with nice dark loamy soil.
It does seem that some of our veggies struggle some recently, especially our corn.
If oak leaves have caused a buildup of some undesireable condition, how can we undo it?
We are in a Northern climate.
Thanks!

Probably just a PH imbalance. Check and adjust with limestone. If you are located in the mid Atlantic or north east it could just be too much rain this season.

A soil test would be very helpful.

Oak leaves will not provide much in the way of the nitrogen or a lot of other minerals that your corn requires. Leaves are not a complete fertilizer.

Keep adding the leaves as they are helping to create that dark, loamy soil but also add manures or other high nitrogen matter. Add lime as suggested if your soil test shows that it is required.

Wayne

There are a lot of myths out there about Oak leaves, but research done by Dr. Abigail Maynhard at the New Haven, Conn. Agricultural Research station found that adding Oak leaves yearly and for several years did not significantly affect the soils pH. The article appeared in Organic Gardening magazine some time back. Back in the 1970's, I think, there was also a report in the pages of OG magazine that showed the pH of various tree leaves with Maple leaves at 3.2 and Oak at 3.7.
Tree leaves also have significant levels of nutrients. All summer the tree roots havebeen taking some nutrients from your soil and moving those up the tree to the leaves where, through photosynthesis, the leaves make other nutrients that are sent back to the roots. When the leaves fall off the tree those leavs still have significant levels of those nutrients to put back into your soil.
Like any form of a relatively high carbon material those leaves, when tilled into the soil could tie up some other nutrients the plants trying to grow there need and the plants then show signs of stress. I would start with a good, reliable soil test to see what might be creating that problem.

Red oak leaves tend to break down slower than many others, but compost like any other. A good compost, whether man made or natural, needs more than one ingredient to support vegetative growth. You have a good layer of leaf mold but unless you have been using a multi-ingredient compost, manure, or some other "green" ingredients, you probably do have some deficiencies in nutrients (especially nitrogen), and corn, especially, needs a lot of nitrogen to flourish.

oak leaves shouldnt be any problem in the garden just do a soil test. Now walnut or black walnut products on the other hand are a big no no. they have a natural toxin to other plants and horses.

My experience echoes a few others' posts here – oak leaves will not harm your soil, but may tie up some of the nitrogen while they break down, so adding extra sources of nitrogen is a good idea.

If you till your leaves, any leaves, into your soil you could see nutrient deficiencies just as you would when you till in any other high carbon material. If you put the leaves on your soil as a mulch you will not see that evenas the soil bacteria work those leaves into your soil for you, and in addition those leaves will 1) help suppress "weed" growth, 2) help conserve soil moisture, and 3) help keep the soil temperature moderate.

My bets are going for: You need some horse manure! Relying totally on organic matter provided by trees and not adding any thing else doesn't seem to add what all vegetables need, especially the heavy feeders. I'm learning that everything needs fed something. My cabbage didn't do squat, probably because I didn't put out enough manure or some high powered nutrients.

After talking with Pepperhead, quizzing the farmers, and remembering some posts from 3-4 years ago... Productive gardens come from Manure!

I'm so sick of these farmers saying, "We don't really put anything on our gardens" Like the stuff just grows magically. Then you find out: "well, we do empty out the chicken house in the fall, but we don't do anything else"

"Uncle Joe brings over a load of Sheep manure and hog manure every winter when he cleans out his barn and we spread that around."

Etc, etc. I know I got the best harvest of tomatoes off of 8 tomato plants that I piled the rabbit stuff on, (on top of the leaves I had piiled up).

Tree leaves, and other vegetative waste, has fairly large amounts of nutrients that the bacteria, the Soil Food Web, will digest and convert into nutrient forms growing plants can use. Many people have very successful gardens using nothing more than vegetative waste, no animal manures (at least deliberately), by using periodic soil testing to see what the soil needs and finding organically, and vegetarian, acceptable sources of those nutrients. Simply piling on a lot of "stuff" can result in a soil that is in an unbalanced state that will not grow the plants you want when you want them.