100% leaf mulch this year - thoughts on deficiencies?

[ScottinAtlanta]

I have decided to use the free and abundant resource of tree leaves this year rather than manure to supplement my beds. The 12 inch beds need about 6 inches added to them. I have collected (thanks, neighbors for your bags of leaves) and mulched about 3000 pounds of oak leaves and other yard detritus, and am spreading thick layers of the mulch on my beds. My idea is that in 3 months of rain and weather, they will break down sufficiently to plant, with extra compost in the holes.

I was inspired to do this by the 1960 edition of the book, The Complete Book of Composting, by J. I. Rodale, which makes the claim that a pound of oak leaves contains twice as much nutrient as a pound of manure.

Question: Are there likely deficiencies I should worry about with pure leaf mulch?

[Redbaron]

Originally Posted by ScottinAtlanta

I have decided to use the free and abundant resource of tree leaves this year rather than manure to supplement my beds. The 12 inch beds need about 6 inches added to them. I have collected (thanks, neighbors for your bags of leaves) and mulched about 3000 pounds of oak leaves and other yard detritus, and am spreading thick layers of the mulch on my beds. My idea is that in 3 months of rain and weather, they will break down sufficiently to plant, with extra compost in the holes.

I was inspired to do this by the 1960 edition of the book, The Complete Book of Composting, by J. I. Rodale, which makes the claim that a pound of oak leaves contains twice as much nutrient as a pound of manure.

Question: Are there likely deficiencies I should worry about with pure leaf mulch?

With pure brown leaves that fell from the trees, you would have a temporary reduction of available nitrogen. It would catch up eventually of course, but for a while it would be locked up in the biology of the soil, like any "brown compost material". Add some grass clippings or similar green material though and you'll be fine.

[PNW_D]

I have a copy of "Manual of Organic Materials" from Organic Gardening 1947 - it suggests, and I quote:

"Despite the relatively high calcium content of most leaves, calcium must be added to leaf compost in order to balance the acidity and produce a neutral reaction for garden vegetables and the majority of the flowering annuals."

[Salsacharley]

3000 lbs! Wow! How many square feet do your 12 beds total?

I saw a TED video someone here linked a couple of months ago that professed that leaves are completely adequate to produce a complete compost. It did say that adding coffee grounds would be beneficial.

I gathered a couple hundred pounds of mulberry leaves and I am planning on making tea with them. I don't have access to oak leaves but I hope mulberry will suffice.

Originally Posted by ScottinAtlanta

I have decided to use the free and abundant resource of tree leaves this year rather than manure to supplement my beds. The 12 inch beds need about 6 inches added to them. I have collected (thanks, neighbors for your bags of leaves) and mulched about 3000 pounds of oak leaves and other yard detritus, and am spreading thick layers of the mulch on my beds. My idea is that in 3 months of rain and weather, they will break down sufficiently to plant, with extra compost in the holes.

I was inspired to do this by the 1960 edition of the book, The Complete Book of Composting, by J. I. Rodale, which makes the claim that a pound of oak leaves contains twice as much nutrient as a pound of manure.

Question: Are there likely deficiencies I should worry about with pure leaf mulch?

[Labradors2]

I've just finished reading "Teaming with Microbes" which suggests that annuals/veggies prefer soil with bacteria to soil with fungi. An indication of soil with a lot of bacteria would be lots of worms. My understanding is that to keep that soil heavy on bacteria, we need to use mulches that are green (not brown). So, as Scott indicates above, grass clippings would be great. In view of that, I would compost the majority of those dead leaves and add a ton of green matter to them.

Linda

[ScottinAtlanta]

Good points, all. I am mixing coffee grounds into the beds as quickly as I can collect them - about 250 pounds a week from our local coffee shop. That should add the nitrogen back in.

Calcium, huh? Let me ponder on that challenge.

Charley, you would be surprised at how small a pile 3000 pounds makes once mulched - it is a total of about 7 cubic feet of mulch.

[BigVanVader]

I use only leaves and my own urine, it works perfectly. Simple is usually best in my experience, plus its similar to what happens in nature. I just help speed up the process a bit. Good luck

[Worth1]

My native pepper plant gets nothing but elm leaves for nutrients and it does great I might water it once a month if I remember.
The soil beneath the pile of leaves I keep on it is sandy loam.

Worth

[ScottinAtlanta]

Let me be clear that I am not composting the mulch first - I am putting the mulch directly on the beds about 6 inches deep. I will be mixing in coffee grounds as available, but am depending on the rains and microbial action to do the work of breaking them down. When planting I will put a healthy few handfuls of black compost in each hole. I will try to add more nitrogen to speed things up.

[Redbaron]

Originally Posted by ScottinAtlanta

Let me be clear that I am not composting the mulch first - I am putting the mulch directly on the beds about 6 inches deep. I will be mixing in coffee grounds as available, but am depending on the rains and microbial action to do the work of breaking them down. When planting I will put a healthy few handfuls of black compost in each hole. I will try to add more nitrogen to speed things up.

The most I have ever done like you describe is 3 inches deep of leaves. (fully chopped and settled 3 inches) Never did 6 inches before. However, I did have a very good year that year. The soil did not get too acid at all, though people told me it would.

Little warning though, 3 inches turns to almost nothing by spring. I had to mulch again with grass clippings in spring. 6 inches might turn to double nothing?

[Labradors2]

That's quite a bit of acidity and carbon. Let us know how it goes and if it works well, I'm tossing this book out of the window {LOL}.

Linda

[drew51]

Originally Posted by Labradors2

That's quite a bit of acidity and carbon. Let us know how it goes and if it works well, I'm tossing this book out of the window {LOL}.

Linda

I saw some references to recent studies and the leaves once composted are really not that acidic. Not acidic enough for say blueberries.
I would not assume just because you read it, or read anything it is correct. Of course if you applied that to this post, you could probably ignore it! What the heck do I know!

[Labradors2]

Originally Posted by drew51

I saw some references to recent studies and the leaves once composted are really not that acidic. Not acidic enough for say blueberries.
I would not assume just because you read it, or read anything it is correct. Of course if you applied that to this post, you could probably ignore it! What the heck do I know!

It's probably true that the leaves aren't that acidic "once composted". However, like bark chip mulch, while it is composting, it is tying up nutrients from the soil. Do we want to do that to our veggies?

I wonder how long those leaves will take to compost for the original poster. Hopefully, before he plants his tomatoes in the spring. I know they would take longer where I live because of our brutally cold winters. Therefore, I'd rather do it in a composter or away from my veggie garden.

As for the book, since it claims to be "A gardener's guide to the soil food web" (revised edition). I would hope that it would be correct (for what is currently known or assumed). Although our knowledge base is changing all the time and it's hard to keep up .

Linda

[ScottinAtlanta]

I will add a little fireplace ash for liming, but judiciously, I think, since tomatoes like a little acid.

[Cole_Robbie]

If you're not tilling it in, then it's going to act as mulch. And there's nothing wrong with that. I think you will have great roots, but they will stay in the bottom six inches.