When greens turns to browns

[Susan W]

This may be covered somewhere back in various posts, but now a good time to mention again with falling leaves. It is my understanding green fresh leaves from plants/trees are Greens in the compost. Once fallen and dried are then Browns. Can be confusing!!!!

[rainbowgardener]

mostly my understanding. Green leaves fresh cut are greens. Fallen autumn leaves are browns, whether or not they have hung around and dried. The difference is because trees are thrifty. Before they let go of the leaves, they suck a lot of the nitrogen and whatever they can use back, leaving mainly the carbon structure.

"Shedding leaves helps trees to conserve water and energy. As unfavorable weather approaches, hormones trigger the process of abscission [from the same Latin root as scissors] whereby the leaves are actively cut off from the tree by specialized cells. At the start of the abscission process, trees reabsorb valuable nutrients from their leaves and store them for later use in their roots. Chlorophyll, the pigment that gives leaves their green color, is one of the first molecules to be broken down for its nutrients. This is one of the reasons that the leaves turn red, orange and gold in the fall. At the end of the abscission process, when the leaves have been shed, a protective layer of cells grows over the exposed area."
https://earthsky.org/earth/why-do-trees- ... eir-leaves

So as soon as the leaves drop, they are browns, because before the tree ever let go of them, it took back the Nitrogen and other nutrients that would make them greens. The same is true of hay vs. straw. Hay is a green, because it is fresh and growing when cut. Straw is a brown, because it stays on the plant until the plant is done with it and has taken back a lot of nutrients.

[imafan26]

It is confusing I had the same problems.

I sorta concluded that fresh leaves, fruits, are greens. Stems, roots, twigs, bark , paper, wood, and old brown leaves are browns. Manure and kitchen waste I treat as greens because they are generally high nitrogen. Browns are more high carbon.

One of the reasons I end up cold composting is because I don't build my pile fast enough so I either have too many greens or too many browns. Too many greens make a slimy mess. Too many browns, I just have a hard time keepin it damp enough to steam.

[Susan W]

Yes, confusing. If the leaves dry naturally on the tree, the theory of nutrients going back in to structure make some sense. Now if green leaves are cut off, allowed to dry, are they green or brown?! Now I am thinking of my comfrey. I forget to cut leaves going along, now throwing some fresh cut green in the 'enriched dirt' pile, turning in. If I cut some to dry on a rack, are they green or brown?

I am not too worried about balance in my pile as there is plenty of dirt (dumped from containers) and lots of worms.

[imafan26]

If you are cutting off green leaves and putting them in the pile then they are green. If the leaves are dried and brown before they end up in the pile much of the nitrogen has already been lost so it has more carbon and is now a brown.

[toxcrusadr]

I think Susan is asking about cutting them green and letting them dry out, similar to the way green grass clippings can be dried in the sun and still retain much of their nitrogen content. Just guessing but I would think this should work with virutally any green leaves just like it does with grass clippings.

[caverdude]

ok so you are saying hay retains much of the nitrogen? And if grass goes dormant and brown then does the nitrogen go back into the roots?

[rainbowgardener]

ok so you are saying hay retains much of the nitrogen? And if grass goes dormant and brown then does the nitrogen go back into the roots?

Yes and yes. Hay is a "green" nitrogen rich for composting purposes. Straw is a brown, because it is allowed to dry first before cutting and the N has been reabsorbed.

[caverdude]

well hay turns brown over time, though it does stay green inside the bail for a period of time. even though it might be brown in color its still a green in composting? Just maybe lower in nitrogen than when it was first cut? And it looks like you were saying yes dormant grass is a brown in composting not a green?

[applestar]

I'm thinking it still applies. The green color in the hay comes from Chlorophyl, that's estsblished.

After the hay is cut and stored, the chlorophyl breaks down. Chlorophyl's Formula is: C55H72O5N4Mg -- so I'm just guessing but the Nitrogen ("green") gets freed up -- maybe combined with the Oxygen --and outgasses into the air? Nitrogen is typically the most volatile and motile out of the three biggies -- NPK.

[rainbowgardener]

That's why I put "green" in quotes. We should get better words for it. It has NOTHING TO DO with color. Manure is a "green" not a "brown" because it is soft, moist, nitrogen rich. So hay is cut green while it is still nitrogen rich, it stays a "green" for your compost pile, no matter what color it turns. By cutting it green, the nitrogen was captured. Leave it stand in the field until it turns brown, the nitrogen has been reabsorbed by then and it is a "brown."

[tomc]

In practicle real-world terms, I dunno if this makes any difference. if the leaf is dried or fresh. Treat it as a brown if dry, and green if still turgid.

Having applied round bales to a compost bin. Opening the bale to admit air does more to speed decomp.