Compost is Magic!!!

I don't know how surprising this will be to the rest of you, but I was really amazed by something that happened whilst I was developing my new growing area. I have very compacted (ploughing for many decades followed by overgrazing by sheep) silty acidic soil, and I'm trying a few different methods of improving it, including sowing some deep rooted green manure plants. See my thread here if you're interested in the project - early days yet though!

One of the things I'm doing is adding organic material, whatever I can get my hands on, to also add structure to the soil. Most of this I have been adding into lower levels of the soil (yes one part I am completely digging over by hand!) but one area I'm not digging over, just trying to improve through plant growth, so I have been adding mulching materials to the top of the soil. Earlier in the summer I scraped off the growing turf with a wheel hoe and sowed some buckwheat, chiccory and a mix including tiller radish, alsike clover and grazing rye onto it. Since I had been having some issues with slugs and birds eating the seeds when I sowed into turf in that area, I sprinkled some compost over half the area - partly to see what difference it made and partly because I didn't have very much - it was bagged tomato compost (Certified EU organic Dalefoot made from sheeps wool, bracken and comfrey) and  left over from shop stock from last year. This is what happened after one week:



You can see clearly the side that has the compost has bigger seedlings with apparently better germination.  Is there something else going on as well as the mechanical effect of the presence of debris?  I'm still a bit bemused that the effect was so dramatic and am trying to think why it had such an effect, particularly on the germination, although I did do it originally for that reason rather than for improved growth.

Even after a couple of months the effect is still visible:



I repeated the exercise recently on the beds I am digging over. In ten days again the effect is dramatic. The size and density of the seedlings look significantly different


Without compost (pound coin for scale)


With compost (pound coin for scale)

The compost wasn't enough to give a complete coating (it was a little bit degraded being old and damp, so tended to clump a bit). I'd really like to try some more experiments, or if anyone else can share their experiences I'd be very interested to see if the same effect is had with home made compost (mine has too many seeds to use on the surface), and less degraded soil. Maybe my soil is just so poor that the effect of the compost is exaggerated.



(edited to add compost details)

Yep, I've been top dressing with compost for the last few years and my veggies have grown much better, compared to previously when I did fertilizer and burying food waste. I cover the beds once a year with just enough compost to cover it, and don't dig it in. I use fully decomposed compost, not undecomposed materials, because I have lots of slugs and snails. My theory as to why it works better than burying food waste? It takes a lot of materials to make compost, so I think that the compost is much more concentrated than the food waste I was adding directly. I'm simply adding much more nutritious organic matter.

Digging doesn't hurt, but it doesn't really do anything either. Time, microbes, and invertebrate action will do the same thing. There's a guy in England who's been doing a trial of compost, same amount of compost in each, dug into some beds and top dressed on other beds, and they get the same yield (the undug bed may get slightly better yields but I doubt it's statistically significant). https://charlesdowding.co.uk/category/trials/ Save your back! 🙂

Yep. I call compost the "black magic" of gardening!

C Lundquist wrote:
Digging doesn't hurt, but it doesn't really do anything either.

I'll let you know in 5 years whether the digging makes a difference! I think that it will take that long to transform the compacted soil I have, which I think will be the plants' deep roots rather than the compost, since I added so little.

The amount of compost I added was much less than Charles Dowding does. He basically plants into compost: putting about 6 inches down to smother the surface weeds, and then topping up every year with more. (There's a link to one of his early videos here). I had either turned over the turf or scraped off as much as I could to remove the weeds and only put down a sprinkling of compost. This was probably much less than the "2 barrows full per 10 sq metres per year" that Garden Organic recommend here which I believe is an annual recommendation.

Not just the plant roots help to aerate the soil, but also fungal mycorrhizae, invertebrate action, and bacterial biofilms, especially if you're adding organic matter to decompose. 🙂

Even a sprinkling of compost I think would be adding more nutrients than spreading raw plant material as a mulch. My cubic yard compost pile has taken 2 years of filling it up to the top with raw materials until it is fully full without shrinking with decomposition. Probably added at least 6 cubic yards of raw materials over that time for that 1 cubic yard of finished compost.

I'll just add a caveat to this praise of compost based on my experience last year:
After I sowed my roots bed I added a little compost from my own compost bin. I think the birds then came to eat all the little creepy-crawlies in the compost and in the process dug up all my seedlings.....so no roots last year. The soil would have been improved slightly and the silverweed that moved in probably appreciated it! So the timing of the compost addition can be critical if it is alive like mine was!

This year, the badgers dug up everything we watered, compost included ... Finally getting a week of rain at last, thanks to ex-Hurricane Erin, after a long, tough drought. Going to be one of the worst harvests on record for England, with much higher than historical average temperatures several spells too.

AC, that's rough.