Compost and timing

[kilroyscarnival]

Major score! At least for me. The guy who services the vending machine company in our office break room just gave me a ton of coffee grounds from the auto-brew coffee vender. I had an 18-gal Rubbermaid bin in my car just in case, and it about half-filled it. There was a little moldiness, as this was apparently two weeks' refuse or more. Got some of it into the compost bin on my lunch hour. That, and the kittens returning from across the street (they had left me!) made for a sweet day so far.

Side note: I joined two Freecycle lists, both served by Yahoo Groups. The one for Orlando has a lot of WANTED, the one for nearby Winter Park has a lot of OFFERs. Go figure. I was able to submit a request for buckets. Sadly, got two items of spam from members, which I mentioned to admins.

The red currants have really grown a lot in the past week! Transplanting them in richer medium and with more space certainly helped.

[kilroyscarnival]

Okay, thanks to everyone for the suggestions and help here. On Saturday, I dumped the whole can as I usually do once a week, and did a complete relayering with some dry yellow leaves, the abundant coffee grounds I scored, and the existing contents of the compost bin. By Monday, it was pretty hot to the touch!

I came home last night to find a big bag on my porch. My boyfriend had a printing order to drop off and brought me his stash of "crap" we have been joking about, his food waste which he's been storing in the freezer. LOTS of banana peels, pineapple rind, a mushy stalk of celery, looks like the clearout of his crisper. I pulsed all in the food processor with this week's fresh coffee grounds/filters from the sales office and home, and spread on the compost and topped (in the dark) with a layer of dry leaves. It needs stirring, but I'll do that in daylight.

I did spread some of the coffee grounds on my "standby" pile of leaves and clippings and such. That too felt somewhat warm last night. I think I have gotten enough nitrogen in there now, and also built enough critical mass to get things going. For now.

[Redbaron]

Congratulations! Silly as it may sound to some, getting your first compost to "kick" really is a major hurdle! You'll soon be on the way to Master Gardener!

I detect a really really fast learner here.

[kilroyscarnival]

Thanks! I was greatly assisted by advice, plus that influx of coffee grounds, plus I think the addition of those yellow and russet colored leaves helped add less compacted dry matter and a little aeration. So far so good.

[Alpinejs]

My interest in the following originated on another thread but this one is likely more
appropriate and hope I can get some good help and answers here.

I have two hoophouses which require some heat at night for Jan. and Feb. It gets down to
about 25 F. now and then. We have the 2nd highest electric rates in the USA, so I don't
want to run electric heaters again. Someone suggested digging a trench in the hoophouses
and filling them with compost which should heat the space, so here are my questions
for you experts.

First, would composting material in a trench of say 1'X1'X8' give off enough heat to raise
the temp in a 12' hoophouse about 8-9 degrees? How long would a well structured
compost mix continue to give off heat in sufficient amounts? What "recipe" would you
use in the trough? I have access to an abundance of horse manure and coffee grounds,
but would have to seek out lawn care companies for grass or leaves as I have neither.
How often would you water the mix and how often does it need to be turned? Bear in
mind that I am more concerned about the heat than the value of the compost nutriments,
but I would not look a gift horse in the mouth, right?

I am intrigued by this concept and hope it is a doable solution to the heating problem.

[Alpinejs]

I should probably have added what the need for heating the hoophouses is.
I have 16 of my current most important tomato plants (for seed) in these
houses and in Feb., I will have about 1800 seedlings in there also, so a freeze
could be devestating, but if the trench concept does work, I don't need to
worry about power outages or timer failures, etc.

[Redbaron]

Originally Posted by Alpinejs

My interest in the following originated on another thread but this one is likely more
appropriate and hope I can get some good help and answers here.

I have two hoophouses which require some heat at night for Jan. and Feb. It gets down to
about 25 F. now and then. We have the 2nd highest electric rates in the USA, so I don't
want to run electric heaters again. Someone suggested digging a trench in the hoophouses
and filling them with compost which should heat the space, so here are my questions
for you experts.

First, would composting material in a trench of say 1'X1'X8' give off enough heat to raise
the temp in a 12' hoophouse about 8-9 degrees? How long would a well structured
compost mix continue to give off heat in sufficient amounts? What "recipe" would you
use in the trough? I have access to an abundance of horse manure and coffee grounds,
but would have to seek out lawn care companies for grass or leaves as I have neither.
How often would you water the mix and how often does it need to be turned? Bear in
mind that I am more concerned about the heat than the value of the compost nutriments,
but I would not look a gift horse in the mouth, right?

I am intrigued by this concept and hope it is a doable solution to the heating problem.

1) I doubt that would be enough. Although I never tried it in exactly your situation, it sounds small. I guess it depends how well your greenhouse holds heat.
2) I never watered mine except at the beginning, but I didn't dig a trench either. I basically build walls with 4 straw bales. Then fill it in with manure to the top and pack it tight. Patrix does it by digging a pit and filling it part way with a barrier and soil over that. Both methods place the plants directly on top with a barrier between. My grow box does drain though. I suspect Patrix does too. Also the straw bales are thoroughly soaked. I also wet the manure.
3) You get a burst of heat right away for a few days then you get less but significant heat for about 1 month. Or at least I did. Perfect for starts in spring. Start them when cold and as the weather warms the compost slowly settles down. It was still pretty warm when I took it down.
4) I personally used a combination of cow, chicken, rabbit manure with just the bedding that came with it when I cleaned the stalls. IE Mostly manure and old hay. But I do know that fresh grass clippings heat up pretty good too!
5) I am not an expert, I just did it as a teen when I was doing my 4H project. It did work though.

[habitat_gardener]

I recalled something about heating greenhouses with compost from the old soil forum on gardenweb, so I googled and found this
http://www.motherearthnews.com/moder...z80mjzraw.aspx
Jean Pain in France was using compost to heat greenhouses, but he had massive amounts of it ("50 to 100 tons of water-soaked brush clippings") and prepared it in a special way.

Google "biomass greenhouse heating" or "compost greenhouse heating" to find more links.

[greentiger87]

This reminds me of the pineapple hotbeds they used to grow pineapples in Britain in the 1700's, but I'm not sure if the model really helps much. Basically they dug a pit, filled it with fresh manure, and then lots of soaked and weakly nitrogen charged hardwood bark (tanners bark, usually charged with urine). The pineapples were grown in pots sunk into this bark, and a cold frame was constructed around it.

The manure provided a strong burst of heat at the beginning, which also warmed up the bark enough to allow for the microbe population to get a stronghold. The bark then provided a sustained source of bottom heat for the duration of the winter.

http://www.buildingconservation.com/...pineapples.htm You can read more about it there.

The wikipedia article describes a different method, with separate compartments for the manure and for the plants:
http://en.wikipedia.org/wiki/Pineapple_pit

For heating air, I think the sheer volume of organic material needed would just be impractical.

[kilroyscarnival]

I don't know what your other conditions are, or whether this is feasible, but what about a passive solar water heater, black tubes with the sun heating water, and collect the hot water in volume inside the hoophouse allowing it to warm the air? You would have to pump the water out to reheat it during the day.

[kilroyscarnival]

Today I got all my neighbor's leaves after he had raked his yard, along with some of my own, though I raked midweek. I about doubled my pile in the back and had enough shredded leaves in my mower bag to make more mulch.

I notice old grass clippings aren't breaking down. I guess I have to get all those microbes going over the lawn as well. Would compost tea do it? Anything you recommend?

[bwaynef]

Originally Posted by Alpinejs

I have two hoophouses which require some heat at night for Jan. and Feb. It gets down to
about 25 F. now and then.

First, would composting material in a trench of say 1'X1'X8' give off enough heat to raise the temp in a 12' hoophouse about 8-9 degrees?

This is the 2nd time I've been in the same boat as you Alpine. I've got a small 6x8 greenhouse that I want to keep just slightly above freezing. I'm considering compost as the means to do just that.

Occasionally we'll get to the upper teens, but usually our lows are around 28ºF. I keep bonsai (or plants that I hope will become bonsai) in this greenhouse for various reasons, whether they are tender, had a rough autumn, or need an artificial boost provided by the warmth/protection of the greenhouse. Eventually, I'll have tomato seedlings in there well past the threat of freezing.

I have (access to) horse manure, all the oak leaves I can stand, Starbucks refuse, and limited lawn clippings as well as whatever kitchen scraps my young family of 4 can generate. I've also contemplated going to the municipal compost place and picking up some of what they offer ...which will likely be very not-composted-yet and very woody.

I plan to build a compost bin in the greenhouse (giving up some ground space for additional warmth along the benches above). The concern I'd have with such a small trench is that it may not have enough mass to hold the heat. Most compost bins are recommended 3-4' cubed ...but that's when all the sides are exposed. With your trench only 1 side will be exposed and the other 3 insulated by Terra Firma so my worries could be moot.

Good luck. Let us know how things go.

ps. 18" inside my current compost bin got to 130ºF for about 2 days, then stayed 100+ for 5-7days. After that, I mixed it up again and it got back to just under 120 for about a day then started to decline. ...Then the battery ran out in my wireless thermometer and I haven't been bothered to go mix it again and fish out the thermometer. I'd think that'd give off enough heat to keep the greenhouse north of freezing for the coldest months.

[habitat_gardener]

Originally Posted by kilroyscarnival

...I notice old grass clippings aren't breaking down. I guess I have to get all those microbes going over the lawn as well. Would compost tea do it? Anything you recommend?

Where are the grass clippings: on the lawn, in a bin, mixed with leaves? They do tend to clump and need to be mixed with other stuff a bit, and they need to be moist but not wet.

[kilroyscarnival]

Sorry, I meant old grass clippings on the lawn. I have been bagging since I started the compost. But before that I used the Fiskars push mower which mulches it and scatters it.

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[dice]

alpinejs: I think you need more volume. 1 foot x 1 foot x 8 feet is
not enough for it to heat up much, even if it was all fresh horse
manure. I would go for a hole 8 feet long and wide enough and
deep enough to fit a hay or straw bale. Then fill the whole thing
with hay or straw bales (hay bales will be higher nitrogen; straw
bales will need nitrogen added).

You could use straw and scatter sulfate of ammonia on top of it
and water that in. No guarantee, but that might do it. (You could
put electric heaters in there with thermostats, so that they do
not actually use any electricity unless the temperature falls
near freezing even with the straw bale pit.)

If the electric heaters turn on, try adding some more nitrogen
and water to the straw bales and see if they heat back up.