Growing in Compost

My first time asking a question since joining Permies and I know I will get some very knowledgeable help and I thank you for it.
So i've decided to move my garden from the ground to raised beds. And I've built some beautiful raised beds  that I am very proud of and wish I was technically savvy so I could show them to you all. But alas, I am definitely NOT technically savvy. After 25 years of bending over and fighting weed encroachment I feel I may be more successful with this method. Not only that, I want to get rid of my rototiller.
So I caretake a large property for someone and have thrown all of the grass clippings, weeds, sticks into a common pile. I'm talking probably 2 yards of grass clippings every time I mow and multiple yards of leaves I pick up in the fall. Needless too say, The pile got so large that there are now actually 4 huge piles. Since the property owner purchased a tractor with a bucket a couple years ago I have been turning those piles and making some beautiful compost. I'm talking yards and yards of compost, not the three section pallet type compost heap. And it is beautiful, rich looking soil. And he vey generously said I could have all of it if I wanted and use his tractor and trailer to take it.
Anyways, I have filled my raised beds with this compost but I am having second thoughts that maybe I shouldn't have done that. Thats because as I sit here the day after filling them I could swear that I once read that it is not advisable to grow in just compost. Or that it is impossible for whatever reason. I just do not remember.
With that said, I started using it as a medium to grow new grass where needed on this persons property. I sew the seed directly into the compost and it grows beautiful grass. That makes me believe either I misread the article or the person who wrote it doesn't know what they are talking about. Either way I know I can get some real life, educated responses from this site.
Any help would be much appreciated. Thank you

I think you have set yourself up for success.
I'm gonna assume you there isn't any spraying of herbicides going on to the lawn grasses that go into the compost piles
Laying down a layer of compost each year is one way to create and maintain a no dig garden.
There may be some kind of downside,  but I doubt it.
If it was unfinished compost , I could see the potential problem, but honestly,  I do just that with some great results.

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I grow things in straight compost and I haven't had issues. I think it will work great. I envy the amount of it you have.

Well I do know that the owner had previously had fertilizer put on the property. I am assuming that it was probably petroleum based just because of the size of the property. Not sure of herbicide but possible. I'd have to ask if the property owner  knows.  With that said, I've seen or heard somewhere that the process of compostiing has a way of taking imperfections out of the soil. I don't know if it is true but I pray that it is.  I was so dumbfounded when he said I could have it ALL qand use his equipment to get it to my house that I never even considered that before I put it in my beds. These piles have been composting for a couple of years.  
I am encouraged that you have had success growing in straight compost.
Thank you for your input.  

Hi, Chuck, I registered for the forum (been lurking for many, many years) just to respond to your question.  I made numerous Hugel beds a few months ago, and the top 6 inches or so are compost made primarily of arborist (ramial) wood chips, grass and white clover clippings, fall leaves (mostly oak), and egg shells.  This compost was created in about a year in a very large pile, built and turned with a compost tractor.  After 1 year, everything was fully decomposed except some wood chips which are soft and spongy but still discernible as wood chips.  

Under the generous layer of compost in my Hugel beds is a thick layer of white clover clippings and tall fescue hay, followed by partially decomposed forest wood.  The bottom of the Hugel beds are 3-5 feet thick chunks of willow and poplar wood.  

I planted tomatoes and bell peppers in one Hugel bed.  As an experiment, I also planted tomatoes and bell peppers in one of my normal garden "mounds", which are basically 12" unframed raised beds of heavily amended clay soil.  I've only had 3 years to pump organic matter into the native clay, but I have added at least a few hundred yards of grass clippings, 20-30 yards of shredded oak leaves, a disgustingly large amount of pond scum and algae, many yards of soy bean straw, thick arborist wood chip paths, kitchen scraps, etc... I consider my normal garden soil to be adequate, but not great, at this point.  

I tell you all of this so you can understand the following comparison:

The tomatoes that I planted on the Hugel bed, growing in nothing but compost, at this point, are twice as large as those planted in the regular garden soil.  The peppers are about the same, although the ones in the Hugel bed look healthier and more vigorous.  Both plants received a small dose of slow release organic fertilizer at the tine of planting, and both were top dressed with some bone meal about 2 weeks after transplanting.  

So can you grow plants directly in compost?  After one month of doing so, my answer is absolutely yes.  But...

Point 1: My compost does not hold water as well as I had hoped.  

My compost is free draining, similar to sandy loam.   (This is due, in part, to the nature of the Hugel bed, since the water has a place to drain.)   The compost holds moisture better than very sandy soil, but not nearly as well as my amended clay soil.  For the first few weeks I watered the tomatoes and peppers planted on the Hugel bed almost every day since the compost would be pretty dry down about 2 inches unless it had rained.  As the plants and their roots have grown, I have watered less.  In comparison, I have yet to water my tomatoes and peppers planted in amended clay soil.  I plan to mulch the Hugel beds with a thin layer of clover clippings and some partially decomposed wood chips.  That should help some.

Point 2:  Compost is not always nutrient rich.

Compost is always good for improving soil tilth, but it is not always as nutrient rich as many believe.  This seems to depend, in large part, on what went into the compost.  Grass clippings have a lot of nutrients if you have enough of them, but they do not seem to add much in terms of texture / tilth.    Wood chip compost is not great in terms of nutrients, but it has a wonderful texture / tilth.  Decomposed fall leaves are the best of both words in my opinion -- decent mineral content and great texture.  So far, my compost + a little fertilizer / bone meal is plenty nutritious, but I am curious to see if the compost has sufficient nutrients once the plants get big and start producing heavily.  

Point 3:  Consider mixing a little clay in with your compost.  

After spending years battling heavy clay native soil, I recently found myself actually adding a little bit of pure clay subsoil to one of my new Hugel beds to help with water retention.  I built a camp fire over some huge chunks of pure clay subsoil.  The heat makes the clay very crumbly once it cools.  I took this crumbly clay and mixed it with compost at a ratio of about 90% compost 10% clay.  The result seems extremely promising.   The clay adds a little more "body" to the compost and definitely helps it hold onto water.  But at only around 10% clay, there is no compaction and no stickiness.  This compost / clay mixture is still free draining, but remains moist a day after watering, unlike the pure compost.  And the clay should help retain nutrients, as well as being a rich source of minerals in its own right.  

That's all I've got. I'll try to take some photos later today of the tomato plants grown in compost vs. amended clay so you can see the dramatic difference.

Hi Jonathan,

Welcome to Permies.

Jonathan A Young wrote:Hi, Chuck, I registered for the forum (been lurking for many, many years) just to respond to your question.  

That's a mighty fine first post you got there.

@ Jonathan A Young - Interesting that you just experimented with adding a little clay, as I did the same thing this spring to some raised beds I made and essentially for the same reason. It's a bit early to tell the long term effect, but at the moment the beds are growing happily.

I agree that not all compost is created equal, particularly if it's made of a limited variety of material. I don't particularly aim for a really hot compost as then it seems as if all the carbon and nitrogen I want to keep are going up into the atmosphere. I've been trying to mix in what biochar I can make to help out the microbes also.

@ Michael Helmersson

I am a recovering lawyer.  We are not known for brevity.  

Jay Angler wrote:@ Jonathan A Young - Interesting that you just experimented with adding a little clay, as I did the same thing this spring to some raised beds I made and essentially for the same reason. It's a bit early to tell the long term effect, but at the moment the beds are growing happily.

I agree that not all compost is created equal, particularly if it's made of a limited variety of material. I don't particularly aim for a really hot compost as then it seems as if all the carbon and nitrogen I want to keep are going up into the atmosphere. I've been trying to mix in what biochar I can make to help out the microbes also.

I, too, have noticed the difference in compost quality when hot composting vs. not-so-hot composting.   I have a 2 acre yard surrounded by an oak-hickory forest, so you can imagine the amount of fall leaves that I get.  When I hot compost them, they turn into extremely fine, crumbly black compost.  Nice stuff, but....  when I cold compost them, they retain a little more texture and plants seem to prefer this.

I am about to harvest the largest heads of garlic I have ever grown.  What I did differently this time is, after I planted the cloves in the fall, I mounted 8-10" of shredded oak leaves on the top and sides of the row, and topped that with an inch or so of white clover clippings.  The garlic had no problem poking through all of this, even as the rain matted the leaves down a bit.  By the spring, the leaf / clover layer was only about 1" thick, and it looked like something between leaf mold and cold compost.   This area is absolutely loaded with garlic roots.  The garlic has grown more vigorously than when I have mulched / side dressed it with fully broken down hot compost. There is something about the decomposed-but-not-disintegrated texture that vegetables seem to love.  

I think it comes down to fungi and mesophilic bacteria making more nutritious compost than the thermophilic bacteria.  I'm not the first to make that point, but my experience is very much consistent with what others have said on the subject.  

Photos of vegetables growing in compost.   When I say growing in compost, I don't mean I top dressed or mulched with compost.  Nearly 100% of these plants' roots are currently in compost.  

All were planted from seedlings on May 21 in SE Michigan.  Modest amount of 3-5-5 slow release organic fertilizer mixed in planting holes and top dressed some bone meal a little while later.  

Tomatoes are indeterminate yellow cherry type.  They are already 2-1/2' tall, and loaded with flowers.  

Squash are acorn.  Incredible growth from these in less than a month growing in nothing but compost.  

Peppers doing great also in 2 feet deep of compost on top of amended native soil.  

Tomato growing in amended native soil... Half the size of the ones in compost.

And finally, since we're on the topic of unconventional growing media... zucchini and yellow straightneck squash growing in 12-18" deep ramial wood chips, laid down 2 years ago when planting austree willlow cuttings for a quick privacy screen.   Photos are from 3 weeks after planting seedlings I started indoors. The willows are now 20-25 feet tall, and the wood chips are about 75% composted.  They are black, spongy, and clumped together by all the fungus that is going to town on them.   I've top dressed the chips with clover and tall fescue clippings every month or two for the past two years, which seems to have really made the fungus happy.  

I started with 2+ feet of chips, and they have shrunk down a lot.  I put at least 100 yards of ramial chips around 30 or so willows back when I was getting 2 or 3 truck loads a day for many months.  

The results have been incredible with regard to the willows, and now I've managed to sneak some squash in there as well.  Part of my squash vine borer control strategy this year is to scatter squash around 5 acres to see if those little bastards manage to find them all.  THey are also easier to spray with Bt when they are out in the open like this.

I have been making compost using woodchips and spent beer grain.  I get a lot of it and share with another organic orchard across the river from me.
I have three cattle panel bins that are 6ft wide, 5 foot long and 4 foot tall.  I am saving this up for an orchard I am putting in this year and since I have a clay soil that experiences capillary rise of water I must mound for each tree.  I have accumlated a large pile of soil, compost and horse manure that I will use to start the mound, then add this compost and then woodchips.  I will use Marco's idea of putting tree limbs on the base to provide a home from beneficial's.

Chuck,

I think you have an absolute bounty of compost!  I, too, grow in a bedding material made almost entirely of compost, but in my case it is wood chips decayed by Wine Cap mushrooms.  My experience in the last three years is that growing in (mushroom) compost, biology trumps chemistry.  That is to say that the fungi in my bedding appear to be doing a fine job of transporting nutrients to my tomatoes just fine.  In fact, I add no other fertilizer at all.

Now Jonathon Young makes some really good points and I should point out a significant difference between our two composts:  yours is bacterially dominated and mine is fungal dominated.  I can't say that one of these is inherently better than the other, simply that we are not comparing apples to apples here.

Another point Jonathon makes is also worth noting--he adds clay to his compost to help water retention.  I do not do this, but I grow on top of a clay base soil so possibly the roots of my tomatoes (and other plants) are tapping this resource.  I also get pretty heavy spring rains, keeping the wood chips/mushroom compost moist till the roots can reach the clay base.

My final point:  I don't think you can go wrong by planting in compost.  Maybe add some clay for water retention if that is a problem, and possibly keep an eye out for nutrient deficiencies.  Want a really simple, really cheap, easily available all-purpose fertilizer?  Human urine.  I will sometimes collect mine for a day in a 2.5 gallon cat litter jug, then fill the rest with water.  This I will pour onto seedlings I have in wood chip compost that may be struggling a bit out of the gate.  The urine gives them just enough nutrients to get started growing on their own by which point they can interact with the compost bedding biology just fine.

These are just my experiences and I hope they can be of help to you.  

Good Luck!

Eric

My experience is that fungal dominated compost works best on my property for the plants that I grow.  Hands down.  

The best compost I have made?  Lay down 2 feet of wood chips, top dress with fresh grass / clover clippings once a month or so.  Don't touch the wood chips.  Wait two years.  Don't touch the wood chips.  Plant into the wood chips.  You will be planting into a thick web of fungus that will dominate the nearly-decomposed chips and make your plants very, very happy.  

My experience is consistent with professor David Johnson's research on fungal-dominated compost.