for the squillionth time.
Our tobacco is taller than my green fingered neighbour has ever seen. Like double the size. Guess there is good nutrition in that part of the garden after all. Not sure why the borlotti beans did poorly nearby. Perhaps they just went in too late. Also by the tobacco, we now have an Echinacea plant in flower. Very pretty too. So that can stay in for a few years until it is time to dig up the root and harvest it for treating winter coughs and colds.
This nitrogen stuff is doing my head in. I thought I had it more or less sorted. Green stuff equals nitrogen. Brown stuff equals carbon. Should have 80: 20 carbon: nitrogen for good compost.
Then a while back I read that wood chip mulch squeezes nitrogen out of the soil which you might want for the plants. Oh. Okay I can work with that.
But then someone tells me that putting fresh lawn clippings on garden squeezes nitrogen out of the soil. HANG ON!! Surely you can't tell me that both ways.
I don't know. Balance is best and all that. But I think I have more to learn about the chemistry of nitrogen and how it becomes active in the soil in order to sort out good advice from rubbish info.
It's better made at home
1 week ago
4 comments:
Fresh lawn clippings are rich in nitrogen, so they won't take any out of the soil.
Something like wood chips that are high in carbon need nitrogen when they decompose, so they take some of it out of the air and some of it out of the top 1-2cm or so of ground. Since the roots of established plants are deeper than 1-2cm, having wood chips in the garden is often not a problem. What's very important is not to turn wood chips under, because then they will really make the ground nitrogen poor. In general wood chips in the garden aren't really handy because they are much easier to put down then remove.
Something rich in nitrogen, like fresh lawn clippings, will need to give off nitrogen when they decompose. They will also do this partly into the air and into the ground. You can tell when something is giving off nitrogen, because it smells like ammonia. The smell of ammonia is an indication of soluble nitrogen like what's in manure, and it's not healthy for plants.
Like you said, with the exception of manure which is brown, most things green are nitrogen and most things brown are carbon. The 80/20 mix you mentioned is a very rough guideline, and it's very possible to have materials with both nitrogen and carbon in them, like pasture hay.
But you are worrying way too much about nitrogen and carbon. You should just make compost, and enjoy your garden! If you don't get the right mix of nitrogen and carbon, you composting will just go a little slower, but otherwise it doesn't matter. It's much more important to layer compost with different materials than get the mixture right.
Thanks Patrick. Interesting comment about not digging the woodchips in.
I am enjoying my garden and not worrying overly about my own compost. What I do like to know is enough to sort out what I agree with and find convincing from outside advice. Your comments about the grass clippings are helpful.
I was just re-reading what I wrote about the wood chips and one thing I forgot to say is that while high carbon mulch like wood will take nitrogen out of the ground, it's only temporary. It only needs it in order to decompose into compost. Once it's compost that goes into the ground, the nitrogen is available for use by the plants again.
So when you use mulch, you don't need to worry about the ground staying nitrogen poor, or worry about adding more nitrogen some other way.
Wood chips are also kind of special in that they are very high carbon, and remove nitrogen very fast. They are very reactive. Something like straw, or almost any other mulching material, is not nearly so reactive and won't remove nitrogen as quickly.
Sometimes if there is a big pile of wood chips, you will see them smoldering or giving off steam. This is because there is a little bit of nitrogen in the bark of trees, and the rest of the wood chips react quickly with this and it generates heat. Sometimes piles of wood chips can catch on fire this way.
When you put fresh wood chips on a live weed, it will quickly kill it in part because it will quickly suck all of the nitrogen out of it. You want to be sure to keep very fresh wood chips away from plants in your garden!
Wood chips are really best used for paths, or around well established ornamental plants, and not in the garden itself where there are young or fragile plants.
In summer when we chopped down trees out the front and mulched them with a friend's mulcher, we needed mulch not paths. So we have wood chip on lots of the garden. It's all doing fine - nature often copes with the unexpected and rebels against tender loving care, or so it seems. Probably won't havce any more wood chip for a long time though.
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