Its my understanding that compost, wood chips, bark, leaves, grass clippings should never be mixed into your soil. It should be used only as a side dressing for your plants. Mixing it into your soil will deplete your nitrogen. I only learned about this last week. It makes sense because my plants were dying & acting funny.
My preference is to compost it first, but I've tilled in many loads of raw material directly into soil. When we lived in Houston, we turned solid clay into a great growing medium doing that. The process of the material decomposing does consume nitrogen and if the decomposition is going on in the garden soil, amending the soil with nitrogen is called for. Easy enough.
[quote="tarheel2az"]My preference is to compost it first, but I've tilled in many loads of raw material directly into soil. When we lived in Houston, we turned solid clay into a great growing medium doing that. The process of the material decomposing does consume nitrogen and if the decomposition is going on in the garden soil, amending the soil with nitrogen is called for. Easy enough. [/quote]
>> Its my understanding that compost, wood chips, bark, leaves, grass clippings ... will deplete your nitrogen.
Grass clippings and leaves, if fresh enough to be green, actually supply more nitrogen than their decomposition consumes. Those are what make your compost pile heat up faster. Other N-rich greens are coffee grounds, manure, biosolids, green plant stems and kitchen scraps.
Wood chips, sawdust, paper, straw, bark and BROWN leaves would deplete N in the soil if you mixed in very much of them, and your soil didn't have excess N to start with. Those are called "browns" or "C" or "carbon sources" because they have so little nitrogen to start with.
You can start with a pure "brown" like a bale of straw, add chemical fertilizer high in nitrogen to start it composting and supply the lac king N, then grown tomatoes directly in the composting straw. It's a style called, unsurprisingly, "strawbale gardening".
Me, I like to compost. You may lose some nutrients if the pile is too rich and gets rained on tgoo much, but I like my beds to be SOIL, and my compost heap to convert the garbage to black gold. Old-fashioned alchemy, probably inefficient, but I love turning that pile and love watching the nasty stuff become wonderful.
behillman - I would not add fresh grass clippings around plants. They can burn the plants as they decompose. Wood chips are best left on the surface as a mulch. They will break down over time and turn into great soil. Kitchen scraps can be buried in a vacant space - it's amazing how quickly they decompose, especially if they are cut into small pieces first.
As to leaves, run them over with your mower several times, then wet them. Add some nitrogen, such as blood meal, and bury them off to one side. The earthworms will change them into rich, black soil.
I also let mulched leaves decompose in 7 gallon pots. After a heavy rain, I stir them up because only the very top layer gets wet. In about six months, I have black soil.
Fresh grass clippings is my favorite mulch for the veggie garden. I mulch it about 1" deep up to the plants and up to 6" deep starting about 6" away. Never had a problem.
6" of fresh grass clippings will stop the most stubborn pigweed from breaking through.
I do have a compost pile but I also love side dressing my compostable material.
Digging it in is just another job I don't have time for.
I do not use fresh cut grass around the plants, I had been burned doing it. the heat from the decomposition is enough to kill the plants so be careful. I do use thick old/ aged clippings so the garden is weed free and i mean weed free!! I do not have time to weed once my garden is established.
I will just find time to harvest. It is golf season so time is precious.
If I didn't add compost to my soil I'd never be able to grow anything!! We have such heavy clay soil that adding compost and other amendments is a must. I've never had a problem with not having enough nitrogen.
We use leaves from our Maple tree every year in the compost pile and also buried in the garden. I have never heard that decomposition depletes nitrogen. I do use nitrogen in the compost pile to speed up the heating process that aids in the decomposition.
If someone would please send a link so that I can follow up on the nitrogen problem. As I said it has been my experience that compost adds nitrogen. But that is only my experience and I do not profess to know it all.
Bark, wood chips and other things that are slow to decompose I do not use. But that is my preference, so I can not speak to their use.
"... Nitrogen depletion is most severe when woody materials are incorporated into the soil."
Then they suggest adding 25 pounds of nitrogen per ton of sawdust the first year, and 12 pounds the following year. Or composting in a pile before incorporating iot intop the soil. Or spreading on TOP of the soil as a mulch.
(They were mostly talking about commercial or municipal waste compost, which apparently is "leaner" than many home composters make. It's all about the brown:green ratio of what you feed your heap. Commercial composters go for the cheapest feedstuff (sawdust, paper) they can sell. If you have more grass clippings or coffee grounds or manure than newspapers and brown leaves at home, your own compost will probably have so much N that it leaches out of the pile in the rain - or enriches your soil with both C PLUS N, instead of depleting it of N.)
" For the people concerned about nitrogen depletion, Master Composters says that as long as the partially decomposed matter stays on top of the soil, there is no damaging nitrogen leaching. That is another reason why they recommend not tilling mulch materials into the ground,"
We use leaves from our oak tree (hubby runs over them with the mulching lawn mower), grass clippings, kitchen scraps (nothing cooked, no meat, no eggs), and other waste plant material. You can also add beer and a local company uses out of date soda to "water" their compost.
Maybe I should restate my post about the nitrogen. All I wanted to say is not to till in wood chips into the soil. Add them as a mulch, because if you till them into the soil, it will tie up your nitrogen. Adding wood chips on top of the soil is a way of not having to water your plants also. The chips hold water, & will water your plants consistantly.