MW
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Do plants "grow" in compost as in soil?

I know seeds sprout in compost, but will they grow?

I use compost as a soil amendment and as mulch to suppress weeds. Is it safe to assume: 1) that compost is compost and soil is soil, 2) over time compost worked into the soil becomes soil--over time being the operational concept here, and, 3) you can't really grow plants in compost even if the seeds do sprout.

Are these accurate conclusions? And if so, do the seeds sprout simply because of the moisture? If you want them to grow into a healthy plant (just for fun since we seldom know what they are), replant them in soil?

Thanks much

mw :?
Mary in Minneapolis

dan1003
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I had potato growing in my cold compost. In fact, I'm growing potatoes in a tower with a mix of compost and straw. If your compost is hot however, then it probably won't have plants growing in it.

I'm not sure compost is best used as mulch. It seems like all the good stuff would wash out pretty quickly, and it's so rich that weeds would really enjoy it.

Toil
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Compost on top of soil works great!

If you have really bad eeosion problems, you need terracing, not better mulch. Then again in a big rain incident there is always erosion even on a slight grade. The best way to fight it is with living roots and organic matter.

The quickest way I can think of to put roots down and work in organic matter is to put compost on top and put seeds in it. If starting with a weed patch put down newspaper of cardboard first. Remember as well that many annual weeds will help you structure the bed. Thin them but don't pull them.

Weeds like the same nutrients as all plants, they are just really good at getting them deep and putting up with wild fluctuations. Compost will help stabilize things in the long run.

Oh and hey, you can mulch on top of it with whatever you were going to use.


I have used this method successfully, despite being against it. I was wrong, and I m glad!
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dan1003
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I stand corrected on the washout issue. I've got a lot of clay which gets compacted by rain very easily, so I've really got to mulch.

Aside from that issue, splash-back onto lower leaves ends up giving me a heap of disease problems. I imagine that compost would be nice and disease free for a while, but I think it would eventually end up harboring much of the same stuff as the underlying soil. Long story short, I'm a big fan of mulch. Straw in particular since it's readily available for me.

Toil
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Good compost is a source for diversity. I would sooner drink tea from garden soil than tea from sterilized medium colonized by whatever.

In beds with good biodiversity (microbial especially), rampant disease is not possible. Yes, edited happens, but on the whole diversity means health.

You are thinking of fresh manure perhaps? Compost that sits on a bed for a year is as safe as anything. In fact, it still contains all the good guys that fight disease, and probably no more or less disease causing organisms than it started with. I have grown lots of stuff in a very deep bed of city compost, and have only felt good after eating from it.



I did mention though, to mulch it if you can. That's food for the good, the bed, and the ugly.
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dan1003
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I feel like I've hijacked the thread here, MW I hope you have your question answered... my apologies

Toil, I agree with what you're saying. I wasn't referring to compost causing the problems, but my bad soil. The problem I've had is such a small amount of compost (I've only had it going for about a year) compared to my soil that it will take time to get the good guys really up and running.

My city also has free compost available, but I've been afraid to use it. Is that what you mean by "city compost"? It would be a great source if I knew others were getting good results.

Toil
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yup, we use city compost from Hamden, CT

I find bits of shredded plastic in there, but that's the way it is. If I had my way I would have a tractor and windrows or whatever to make really good compost.

You know, splashing is not just a disease thing. A lot of stuff gets around by splashing. But some crops are just better without the grit. Hay and straw is great at preventing that. It would ease your mind as well.
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soil
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i grow in pure compost on an almost daily basis. plants love it!
For all things come from earth, and all things end by becoming earth.

Joyfirst
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Me too. I have a mixture of vermiculite, compost and peat moss. No native soil at all. There would be one problem though - since that kind of soil is very light - bigger plants like tomatoes would certainly require support, but I would give it anyway in any soil for them.
I use rock dust too from slower release, and I am thinking about getting biochar - half burned wood(ground up), which supposed to keep nutrients inside traped in the dirt, even though it doesn't have any nutrition by itself. I am waiting untill we go camping for that one-I live in the city.

Trader
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Potatoes in compost.

I have planted my potatoes this year in a mixture of compost and soil. This I have done in plastic carrier bags (shortage of space) and the method is described at https://www.save-money-guide.com/gardening-diary.html under the March entry.

They are doing absolutely fine and I am aiming at earthing them up more than once to see if this increases the yield.

The potatoes are early Rocket and I am making a point of watering them (when necessary) with manure 'flavoured' water - entry for April, 2009.
All the flowers of tomorrow are in the seeds of today.

LynnDG
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Last year I had whole tomato plants (bearing fruit!!!) growing out of the ventilation slits of my compost bin. I've also had cantaloupe, cucumber and acorn squash. If I don't turn it for a few months in the early Spring/early Summer, Im guaranteed to have little plants holding on to all the sides making it impossible to turn without chopping it up first! :?
lynn
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engineeredgarden
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I grew sweet potatoes last year in large containers with only compost in them, and they performed very well for me.

EG

Joyfirst
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Compost is not all the same. Hot compost doesn't have weed seeds, so it works well for mulch, if you use thick enough layer. It is not as fertile for the plants though, because it doesn't have much microorganisms either. Cold compost has seeds, but it also has microorganisms, that are very good for the plants. Now both types of compost can be rich in variety of minerals, if it is made from variety of stuff like home made compost, or pretty weak in that regard, if it is made from one material, like a lot of comercial compost. That's why Square Foot gardening book recommends buying at least 5 different companies compost to increase chances of richer compost.
As far as city compost goes, I got some from Los Angeles, and it looked very rough and plants planted in it barely growing, so I am adding rabbit manure and other stuff to help it. The plants grow about 5 times better in my own compost. Now I got Santa monica compost which looks much darker, and it stinks bad, so hopefully it has a lot of manure and things will grow better. I will let you know in a month or two.

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Gary350
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I tried a 50/50 mix of compost and soil last year for my potatoes. I also applied some Murate of Potash and some Super Phosphate. My potatoes didn't grow any better than they have in the past. The plants looked great but the potatoes were the size of golf balls and some smaller. I have better luck with red potatoes than white potatoes I think it is too hot and dry in TN to grow good potatoes.

This year I am doing an all compost potato bed. I planted 3 types of potatoes so we will see what happens.

I use my home made compost in plant trays to sprout seeds. The seeds sprout but the plants don't grow. The only way I can make the plants grow is miracle grow plant food or I mix dirt with water and use the water to water my plants.

I save my wood ash from the wood stove and add it to my compost to increase the potash. I think compost is pretty low in potash, phosphate, nitrogen so it needs all the help it can get. Manure or urine adds nitrogen. I'm not sure how to add phosphate to the compost other than super phosphate.

Trader
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I have been reading all the posts with great interest. I am in the UK and have been experimenting growing potatoes in plastic bags as per my page [url]https://www.save-money-guide.com/gardening-diary.html[/url] The compost mentioned is 'bought in compost' and is peat based.

I have ten of these bags and the question is can I use this large amount of 'compost' next year? Normally I would rotate my crops in the garden, therefore I suspect my choice of re-use for this compost is limited.

All advice greatly appreciated as I do not want to let such a large amount of 'compost' go to waste. Many thanks.[/url]
All the flowers of tomorrow are in the seeds of today.

Toil
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Gary350 wrote:I tried a 50/50 mix of compost and soil last year for my potatoes. I also applied some Murate of Potash and some Super Phosphate. My potatoes didn't grow any better than they have in the past. The plants looked great but the potatoes were the size of golf balls and some smaller. I have better luck with red potatoes than white potatoes I think it is too hot and dry in TN to grow good potatoes.

This year I am doing an all compost potato bed. I planted 3 types of potatoes so we will see what happens.

I use my home made compost in plant trays to sprout seeds. The seeds sprout but the plants don't grow. The only way I can make the plants grow is miracle grow plant food or I mix dirt with water and use the water to water my plants.

I save my wood ash from the wood stove and add it to my compost to increase the potash. I think compost is pretty low in potash, phosphate, nitrogen so it needs all the help it can get. Manure or urine adds nitrogen. I'm not sure how to add phosphate to the compost other than super phosphate.
if your compost lacks nutrients it is likely not compost but a single rotted food source.

All those microbes are made of C, N, P, K, and the rest of the alphabet. Diverse food therefore makes diverse nutrients because it makes diverse microbes.

Just don't look for them with a soluble nutrient test.
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