Anyone turn leaves into compost?

I’ve accumulated a big pile of leaves over the last two fall seasons. I raked them up from around the property and dumped them a convenient place along the back fence.

I don’t really have time to bag them up or chop them up with a lawnmower. The big pile looks fine where it is for now but I was hoping it would turn into good quality dirt that I can use for other things around the yard.

Can I just let the leaves sit there for a few years and keep piling more on top every fall? Are there any good tricks to make this more efficient, like adding chemicals or worms?

Be careful about using leaves to composting. Certain kinds of leaves (I specifically know of oak, but ther may be others) contain a preservative chemical called tannin that slows the rate of decomposition and is thus bad for composting. (I knew that high school science project would pay off some day.)

Oh my. I’ve got nearly 100% oak leaves! And yes, they are acting very weather resistant even long after they’ve fallen.

So I’m stuck with a huge pile of leaves that does nothing but look pretty and get bigger every year?

I used to compost my leaves, but since the groundhogs moved in and the Canadian hemlocks on the south side of the property got too tall, I don’t garden anymore. But I digress…

Yes, you can just pile them up, and they will eventually break down without you doing anything. If you want to expedite things, the trick is to add green matter to the leaves, which probably won’t be happening this time of year. But starting in the spring, you can add grass clippings and other green garden waste. You do have to make an effort to layer the grass with the leaves. Otherwise, the clippings get all slimy and stinky and nasty. But the green material will help heat up the pile and break down the dry material.

Turning the pile also helps.

ETA: Even oak leaves will break down eventually. I have mostly oak leaves, too.

The leaves alone will take a while to break down but that doesn’t mean they’re useless. According to this site, oak leaves have lots of compounds that are desirable for compost. It suggests shredding the leaves and giving the compost access to soil below (i.e. don’t compost directly on your lawn) and adding plenty of nitrogen rich organic wastes. According to the same site, proper compost techniques can reduce the time it takes to break down oak leaves from about 2 years to about 6-8 months.

Disclaimer: This is getting away from anything I have experience with. My old science project was specifically about the effects of tannin, rather than ways to work around it.

oak leaves take longer than most other leaves.

mix with grass clippings, throw in some dirt.

turn the pile one per week, keep moist.

One of my mom’s nieghbors was a composting fanatic. She was very picky about what leaves she would take.

I don’t remember specifics.

millipedes are helpful as are worms. they will find the food and dwell there.

Incorporate the oak leaves directly into the soil you plan on gardening in, don’t let them sit on top, and add some pulverized limestone at the rate of about 2-3 lbs per 100 sq ft. If you want to hasten decomposition, add a granular fertilizer, something like 12-12-12, or a similar ratio.
Be conservative with the granular though because when the organic material fully decomposes the nutrition from it will be released into the soil, including N, which even a little too much of will make your plants grow tall and skinny.

If you have the space, they can be composted with minimal effort by creating two baskets or crate-style compost stacks - open to the soil at the bottom - the first one needs to be big enough to accommodate the whole crop/fall of leaves from one year. The second can be a little smaller.

The leaves will compost naturally over a two year cycle without any maintenance - especially if you mix in some grass clippings when adding them, or add a little (male human) urine. Once in full swing, you’ll be able to empty crumbly compost out of the smaller container, turn the (year-old) contents of the larger one into it, then stack the current year leaves in the larger one.

Consider though that the organic matter will decompose more readily when you introduce it to the soil - turning it and mixing it in. Unless there is a reason to have the compost separate (reducing weed seed population present in the organic matter that you’re using), putting compost directly where (and mixing it in) you want it, where your garden is rather than a separate compost heap - saves the labor of the double handling. And more.

The best structural and nutritional soil contains organic matter in various stages of decomposition. The plants can simply derive their soil nutrients from a chemical medium, but the healthy fungi and bacteria in a soil will increase the surface area avail for plants roots to gather nutrients - linking up with those organisms in a symbiotic relationship.

Also, a little tidbit about humus, the product of organic decay in soil… there is something called cation exchange, which in this horticultural case is the soils ability to hold nutrients through naturally occurring electrical charges. It helps resist the nutrients from being leached and rinsed through the soil. Clay has a high cation exchange rate, is good for holding nutrients, it just does not hold much air at the same time. A soil needs a proper ratio of air to water/nutrient solution for the plants to grow well. Although above ground plants parts use CO2, plant roots need oxygen. So clay particles alone, although are great at holding nutrients, do not maintain a good air ratio.That is the problem with clay, no air. Imagine the clay particles like a deck of cards stuck together, you need to put particles between the clay. The best way to do this is with addition of organic matter. Sand can be hauled in but is too physically heavy for its good, and offers no nutritional value like organic material.
Back to humus, the sticky black dirt byproduct of the rotted leaves and organic matter. Humus not only encourages organisms to populate the soil which then act as mini rototillers, tilling and introducing air into the soil, but humus has approximately 10fold the cation exchange rate than clay particles.

Anyways, there is no faster way for organic matter to decompose than mixing it right into the ground, soil particles surround the organic matter with moisture and esp beneficial bacteria and fungi that will greatly speed up decomposition. and it makes sense from several standpoints to do this and make your compost pile the garden and not a separate spot.

One good reason for a compost pile is to try to deal with organic material that contains weed seeds. Composting can help reduce, or if done right, eliminate weed seeds. But if your organic matter is relatively free of weed seeds, ask yourself why you might benefit from having separate compost pile, rather than making your garden the compost pile (sheet composting) and mixing the organic matter directly where the plants are or will be growing. Organic matter will give you the best benefit when decomposing right in your garden dirt, save you the step of double handling, and will rot very quickly when mixed in the ground. So it depends on what you want to do. If you want to have popcorn 8.5 feet tall like mine, and tomatoes plants spilling over 5 foot fences, consider that plants can only take up so much nutrients at once. If other growth conditions are good, the bacteria and fungus present in soil, a product of the rotting organic matter, will increase many fold the plant roots’ ability to link up with and absorb nutrients from soil.

Thanks for the replies!

I didn’t intend at first to have a compost pile; I have just ended up with a 25 foot wide, 3 foot high pile along the back fence (the product of two years of raking up oak leaves)

I will try mixing and wetting the pile, and adding grass clippings. (I’ve noticed that the oak leaves have no trouble turning into dirt when they are stuck in rain gutters). The granular fertilizer and worms sound like a great idea too.

lone cashew - that is very interesting… I don’t have a garden yet but I can certainly try planting things within this pile of oak leaves (tomatoes, pumpkins…)

Mangetout - starting next spring, I may transition to using two containers as you suggest, that does sound very efficient.

lone cashew - what you’re saying sounds contrary to stern advice I’ve seen time and again in all sorts of gardening books (including quite reputable ones), however, it sounds like you really know what you’re talking about - so could you comment on whether it is at all true that composting in direct mixture with the soil, in proximity to growing plants ‘steals’ nutrients (esp. nitrogen) ?

if you have the space using two piles rather than two containers/bins might work better.

advantages to both systems.

containers look neater for city or manicured lots, can fit more material into a smaller space, doesn’t dry as quickly, so you might need to water less. containers are also harder to work with.

piles can hold whatever large gardens and yards can create (25 x 3 x whatever is a big pile). you can turn a pile easily with access to all four sides and by throwing it into an immediately adjacent space. collecting finished compost material is easy.

for a big garden and lawn you can do multiple piles so as to not have to haul material far. you can make a hot pile specifically to kill seeds from weeds or other plants you want to control.

To fellow greenthumb Mangetout - besides factors like temperature and avail moisture content, Carbon to Nitrogen ratios play a huge role in determining the potential for organic matter to rot. Nitrogen is great food for bacteria and fungi, Carbon not so much - at least in the short term.
What happens when introducing high C/N material into your garden soil, a temporary Nitrogen deficiency is created, as the microbes surrounding the organic matter, in effort to break down that stubborn Carbon, will borrow the Nitrogen content from surrounding soil particles. For this reason, material like sawdust, or wood chips, which have a high C/N ratio - I would be cautious about adding a lot all at once - at least in the soil you’re gardening in at the moment (or will be soon), because of this borrowing of Nitrogen. Gardener can add some N fertilizer to offset this temporary deficiency, and this can work just fine - but it’s difficult if not impossible to know just how much to add - keeping in mind all that Nitrogen will eventually be released into the soil when that stubborn carbon material finally breaks down.

Take for example grass clipping which when fresh and green have a relatively low carbon to N ratio of about 15 to 1, while something like sawdust or wood chips will have a ratio of several hundred to one.
Dried tree leaves will have a C/N ratio of somewhere around 50 to 1, which isn’t too shabby- not too high a C/N ratio to tax too much the N content of the soil.

It depends too though on how dry the leaves are (the greener the content the better, which is always the case when we are talking about composting) and the sheer quantity of leaves you are putting in. It has never ceased to amaze me just how much organic matter (like tree leaves) the ground can swallow, esp if you have something like a rear tine tiller, that can really chop up and stir in those leaves.

I still recommend though adding some granular fertilizer along with the leaves, something with a 1-1-1 ratio (not a high N fertilizer, but one with this ratio of the three primary nutrients, N-P-K), like 12-12-12 - a commonly found analysis. Also, most organic material has a potential acidity, and esp oak leaves, or pine needles (our scourge here in the North country). So add a little bit of pulverized lime, something around the rate of 2-3 lbs per 100sq ft. You don’t need a spreader for this either. I have had good luck for years spreading lime and even granular fertilizers using the “feeding the chickens” technique. With a little practice, one can get pretty good at this too, even covering areas an acre in size quickly and reasonably evenly - cradling the bag of fert or lime in one arm and cupping and flinging the material with your other arm/hand.

You won’t get much to grow in the immediate pile of leaves, they will have to be churned and mixed into the soil fairly well. If you don’t have a rototiller on hand, you can use a soil fork - but esp if you’re going to go that labor intensive route, it would really help to chop up those leaves with a lawn mower first. This can be a lot of work. Do you have a rototiller, LC Strawhouse?

I don’t have a rototiller so going that route sounds like more work than I’d bargained for right now. But, where would I get those special bugs or worms to add to the leaf pile?

Okay, I see in your OP that you didn’t have time to chop them up with a mower, sorry I missed that. Like others have said, mixing in a little bit of soil into the compost heap is a good idea. It’s not that there aren’t already plenty of microbes in the leaf pile for it to decompose just fine; but mixing in some soil will particularly aid in separating those leaves a little bit, get some air in there.

Those leaves sticking together like a deck of cards limits Oxygen content in the pile. If you’ve ever heard about material resisting decay in a low Oxygen environment - like stuff stacked deeply in a landfill - this same phenomena applies to leaves densely packed in a compost heap with little air spaces.

Obtaining special microbes for a compost pile is a gimmick and an absolute waste of cash and labor.

All you really need for the leaves to rot is O2 and moisture. Again, if you can add a little bit of granular fert to the pile (like a measuring cupful of 12-12-12 or something like that), this will help it rot faster too.
But like I said, air(O2) and water are the most important factors to consider; and how much labor you want to put into this - turning the pile, adding soil, fert - is all up to you.
If it were my pile - for the little labor and cost required - I would be adding some pulverized lime to the pile as well. It’s inexpensive, easy to get, easy to apply, and just a cup full or two on the pile will really help.

So we had better turn you loose, let you get to work. :wink:

millipedes live under leaf cover (detritus), build it and they will come. worms will also find the bottom of the pile given time. both are always looking for good things to eat.