100% leaf mulch this year - thoughts on deficiencies?
 

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 [URL="http://www.amazon.com/s/ref=dp_byline_sr_book_1?ie=UTF8&field-author=J.+I.+Rodale&search-alias=books&text=J.+I.+Rodale&sort=relevancerank"]J. I. Rodale[/URL], 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?

[QUOTE=ScottinAtlanta;439387]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 [URL="http://www.amazon.com/s/ref=dp_byline_sr_book_1?ie=UTF8&field-author=J.+I.+Rodale&search-alias=books&text=J.+I.+Rodale&sort=relevancerank"]J. I. Rodale[/URL], 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?[/QUOTE] 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.

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."

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.



[QUOTE=ScottinAtlanta;439387]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 [URL="http://www.amazon.com/s/ref=dp_byline_sr_book_1?ie=UTF8&field-author=J.+I.+Rodale&search-alias=books&text=J.+I.+Rodale&sort=relevancerank"]J. I. Rodale[/URL], 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?[/QUOTE]

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

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.

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

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

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.

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

[QUOTE=ScottinAtlanta;439431]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.[/QUOTE]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?:twisted:

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

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.

I could lightly till it in - do you think that would improve the overall soil conditions 3 months hence?

I would leave them as the top layer just to be on the safe side. You'll get a lot of Hugulkultur-type beneficial bacteria and fungi by using them as mulch.

[QUOTE=ScottinAtlanta;439445]I could lightly till it in - do you think that would improve the overall soil conditions 3 months hence?[/QUOTE]
I think you will be better off getting it into the ground. I once added about 4 inches of leaves straight onto the garden. These compacted down over winter and the ground took a long time to warm up in the spring due to the density of the leaves, resulting in a soggy mess.
Now I shred everything and till the whole garden in the fall after adding the leaves.

According to "Teaming with Microbes", tilling isn't good for the soil because it destroys the soil structure, worms and other critters that live there.....

I always rather nervous about putting my trowel into my veggie garden because I usually manage to nail so many worms. Now I will be even more neurotic about it!

Linda

Beeman, I understand your point, but these are not whole leaves. They are finely shredded leaves, twigs, etc, put through a Craftsman chipper. They are much more porous to water than whole leaves. Based on this useful discussion, I think I will not till, but will mix in coffee grounds and lightly dust with fireplace ashes, and other wise leave to nature and her worms.

Agreed, tilling isn't recommended from what I have read/been told. My normal routine is to take my leaves every fall and divide them equally on each vegetable bed I have, regardless of the amount...I have never had it be too much, and have had them as thick as 2ft. I add urine, gypsum, a little wood ash and whatever coffee grounds I can get. Then I just leave it be until planting. I will cover with manure if I have it, but I have planted straight into the partially composted leaves as well and everthing did great.

You folks are great! Exactly the discussion I needed.

I have about five inches worth of about 80% mulched oak leaves and 20% grass clippings from the last few passes my husband made over the lawn with his Walker mower. One of my beds was down a couple of inches of soil and I just didn't want to buy and transport more compost to top it up. I lightly turned it in with a pitch fork before the ground froze. This is the first time I've tried this, so I'll have to find out how it works out next year.

Scott, please keep us posted on your results.

[QUOTE=ScottinAtlanta;439387] ... Question: Are there likely deficiencies I should worry about with pure leaf mulch?[/QUOTE]

Potash is the major one. Calcium is next. After that I'd be concerned about the species of trees contributing to the mulch as some introduce toxins to their leaves in the Fall by an evolution-motivated mechanism to control upstarts of annuals and occasionally of competitor perennials.

Thanks, Richard. I avoid the pecans, which are numerous here in Atlanta, and focus on red oak, white oak, water oak, and maple leaves. I have the rare luxury of choosing leaves since there are literally hundreds of 60 pound bags of leaves sitting on the sidewalk awaiting pickup on any given Fall week here.

I did this for 3 years at my old house and it worked great. I built raised beds and filled the beds with shredded leaves in the fall every year. I never tilled. The beds had tons of worms and the soil stayed moist longer, thus reducing the need to water all the time. I moved last year and need to start again. The first few times you mow the lawn in the spring, you can collect the grass clippings and throw them in as well.

Scott, adding some real wood ash and agricultural gypsum can shore up the K and Ca deficiencies. Somewhere on these boards I recently posted amounts.

Between bacteria as Cole_Robbie mentioned, and the nutrients that are released/made available from worms and insects, you will have absolutely no problem with leaves. Coffee grounds are a good addition, but you need to add them in moderation. They are still highly acidic in the spent condition.

I'd be in the same camp as the other fella who suggested having a daily whiz in the mulch around your plants. If you can get away with it, you'll be well rewarded. :)

I can see my neighbors watching as I stand over my beds contributing to a micro-nutrient deficiency. I don't think that will enhance demand for my vegetables.

That's what pee...t pots are for. :))


[QUOTE=ScottinAtlanta;439554]I can see my neighbors watching as I stand over my beds contributing to a micro-nutrient deficiency. I don't think that will enhance demand for my vegetables.[/QUOTE]

[QUOTE=ScottinAtlanta;439554]I can see my neighbors watching as I stand over my beds contributing to a micro-nutrient deficiency. I don't think that will enhance demand for my vegetables.[/QUOTE]

Just for clarification (pun intended) ...

The primary constituents of human urine are N, P, K. These are also primary -- not micro -- nutrients for plants. But in terms of the garden bed, there's not enough K in quantity to make a difference. For many crops (including yours) the proportion of N to K should be about 1 (N) to 1.5 (K) by weight for best outcome -- given everything else is horticulturally sound. Your present situation will provide plenty of N but fall short in K.

Calcium is classified as a secondary -- not micro -- nutrient for plants. You'd have to be suffering from hypercalcemia to provide Ca through urine to your plants. The trees won't be dropping it either.

The micronutrients (Iron, Copper, Manganese, Zinc, Boron, Cobalt, Molybdenum) -- esp. those in the electrolyte series are important for disease resistance in many plants. I believe you will get them through your mixture of oak leaves.

If there are any actual worries about calcium - which is often present in soil in plentiful quantities - and one is inclined to stay organic, you can always add Calcium Carbonate or Citrate, (dolomite only if you need to alter PH) or even just good old ground egg shells. We keep a coffee grinder specifically for the task of reducing them to useable particle size. It doesn't take too much. Generally, just mixing a few spoonfulls around the root ball will do you for the growing season.

I always get naysayers about egg shell calcium, but for me, it gets used in sterile mixes, and I have yet to ever get BER, or calcium deficiency. Aerated compost teas are also good sources of calcium. I use them as both a root soak and foliar. They don't have to be used 1:1. I have used as weak as a 20% concentration.