What's Wrong with my Black Walnuts?

We found several very large, well established black walnut trees on our property when we moved here. The trees look to be perfectly healthy without any major issues that I can see. So this past fall, we excitedly scooped up the nuts and cracked them ... only to find that the nuts hadn't really developed inside the shell. There was nothing more than a thin, oily membrane where the nut should be. In some cases, there was mold growing in the cavity.

Any ideas? I'm clueless.

Squirrels can weigh nuts and determine which ones are hollow and which ones are good. Did the squirrels beat you to the harvest?

Are you harvesting this year's nuts?

What percentage were good? Enough to make cracking worthwhile?

Can you tell by looking at the husk or shell which ones are likely to be bad, so that you don't actually have to crack them to see?

I think we were pretty much neck and neck with the squirrels. We were scooping up the nuts almost as soon as they dropped, so I'm sure we got this year's nuts.

The nuts all looked the same. I couldn't tell by the outside whether there was a nut inside or not. And no, we definitely did not get enough good nuts to justify all that work.

A lot of trees produce inferior nuts, either from genetics or problems with pollination. I see some stands of black walnuts that you are lucky enough to get nuts off of every 10 years while good producing trees produce decent crops every other year and fewer trees will actually produce every year. That is the nature of seedling trees, if you want a regular crop then it is best to graft trees or buy grafted stock.

On another note, test crack some nuts during harvest to see if the nuts are worth harvesting, that is what I do, I scout out areas that have good producing trees while most trees in my area are not nut producers. After you harvest and hull the nuts clean them by putting in a bucket of water, any nut that floats is a hollow nut that you throw out, that is called the float test and is a common method used by nut gatherers.

If you left them on the ground until they turned black then moisture seeped in and started decomposition. You can keep them in the black hull but they must be off the ground. I have a couple hundred that are still good from wild trees but I have them on pieces of plywood. But yeah just next year gather them off the ground and the dryer they are the better.

The hulls can turn  black and the nuts will still remain good for a long time, the only thing that can happen is that the nut meats can stain after a prolonged time but over half of the 6000 lbs. I harvest a year are black husk, it has nothing to do with whether or not the nuts meat is developed or not.