What do you SFG'ers think about using 100% compost in your raised beds?

I don't think much of it. Soil and growing media need more than compost.

Dan

Dan, What would you think about 2/3 compost and 1/3 peat moss? Any other ideas? Thanks!

steve - I just filled a new box (12" deep) with 80% homemade compost, 10% coarse vermiculite, and 10% peat moss. This was done out of necessity, and normally I use mel's mix in all of my beds. Here's the thing about the new bed.....The depth certainly has alot to do with it - but the moisture retention is fantastic! I have a moisture meter that I probe every box on the property with, and this was a surprise to me.....

EG

Has anyone ever had one of their veggies germinate and grow out of their compost pile? With sun and moisture these volunteers are often much healthier than seedlings which have been nourished and pampered.

Steve, the fact is vermiculite and peat moss contribute NO nutrients to the mix and are ONLY there for water retention. "Mel's Mix" was developed to be light weight but retain water and contain all the required nutrients for what were basically very large containers. His original beds had bottoms.

So if you a building your beds where the plants will have access to the soil below, I wouldn't bother with the vermiculite and peat moss. Plus many here complain when used, vermiculite and peat moss require daily watering.

There is another post on here saying that some vermiculite is, in fact, treated to repel water.

I would want a soil test of the ground soil and the compost going in bc if you are using 'landfill compost' - fact is it could have anything under the sun in it. Even unknown chemicals which may or may not be completely broken down.

There is no substitute for a baseline soil test.

JMMO - Just My Meaningless Opinion

My opinion would be, if you can afford it buy a couple of bags of each of the vermiculite and peat moss (about $63) then get as much free/cheap compost as you can get. I do not worry about getting the 1/3, 1/3, 1/3 mix, but I do like to have some of each in my bed, when I can. I think that the important thing is that you have organic matter.

Good gardening, Mary

I have some beds with mel's mix, some heavier on the compost than others. I also have beds with just compost, the soil from the yard and a little peat mixed in - no vermiculite because I couldn't afford it.
All beds are growing well.
I think a member here, John Best, may have had at least one all compost bed... I'm trying to remember from quite a while back so it could have been someone else. His is just the name that popped to mind as I tried to recall who it was. :)
Because you are on a tight budget just use what works good for you. I would skip the vermiculite, buy a bit of peat moss and mix it in with the compost you get for free. Things have been growing in the ground for millenia without vermiculite and peat :) . I'd much rather have a garden now than wait until I could afford each little extra thing. The stuff will grow! I had a broccoli plant that I threw into a pile of leaves and it rooted there and grew better than the ones in the boxes! :)

Steve, I'd lean toward EG's answer, as you'll likely see over the season that settling will make plant roots unhappy, so you need something coarse in there to create pore space. If you can't do the vermiculite thing, try some tiny wood chips (here they are marketed as bark fines). Compost is adequate WHC and addition of peat for moisture retention IMHO is unnecessary but it changes the chemical composition enuf to make it OK.

Regardless of your decision path, enjoy.

Dan

It looks like I will be following EG's advice. I am going to be building 12" beds as well. I think I'll buy as much peat m moss as I can afford and use compost for the rest. The idea to use wood chips is one I am going to consider as well.

I filled mine with a load what was marketed as "garden compost".

"the compost is made with wood chips,grass clippings,leaves,plant debris,dirt and is composted for about 7-8 months then stock piled for 1-2 years then screened to about 3/8"

So far it seems to be great, but this is my first year with it. It does have tiny bits of wood chips. The surface occasionally will look dry, but will be wet an inch down and seems nice and light. My seeds are germinating in it just fine.

I will probably just plan on supplementing with my own compost from here on out, but we will see how it goes.

ali

Here is a link that might be useful: Garden pictures/blog

Hi Steve, I come down on the side of 100% compost and agree with Gumby 100%. Do an image search on google and take a look what kind of vegetation is growing on peat bogs or silica mine spoil piles. Where does Mother Nature add either one of these to her humus for air and water retention? Emulate her and you will have a beautiful garden.

John

Here is a link that might be useful: John's Journal

Gumby - I'm definitely gonna grow my potatoes in the compost piles next February, because the potato peelings added to the piles all sprouted really well!

EG

When I built my beds last year, I filled them "lasagna-style" using very aged/composted horse manure as the main ingredient. There is some dirt in there -not good soil, a sandy feeling fill dirt- but most of it is OM. It did shrink down about 1/3 over the summer but mulch kept it covered,and stuff still seemed to be doing fine. I added no peat, no perlite, no vermiculite. I went with what I could find when I built and all the ingredients were free.

Please ignore the overcrowding... :-)
These are my first raised beds, so while I can't speak long-term, I was happy with it.

Here is a link that might be useful: Tales of a Transplanted Gardener

This year is my first year with the raised beds and square foot garden. I did not have enough money to put vermiculite in all of the beds so I have decided to do a little experiment, I have one box with my dirt and Miracle grow garden soil, three boxes with Mel's Mix, one box with Mel's mix and my dirt ( I was running out of pure mel's mix). Three boxes with compost, peat, and my dirt. Finally, two boxes of compost and my dirt (ran out of peat). So at then end of the season, I will look over my journal and see what had the best yield and to help me decide if I need to buy more peat and vermiculite next year. It may seem like alot of boxes, but most of them are only 4x2 foot boxes.

I would fill it up with whatever you can get! Cost is an issue, so don't go crazy spending money you can't afford. Keep the boxes open on the bottom, add some vermiculite if you can and forget about the peat. In my opinion, the peat is mostly a filler. Yes it retains moisture, but so does compost. The vermiculite will also hold moisture. The peat's going to keep the soil light, BUT compost isn't compacted, and won't compact too much, if you put some vermiculite in it.

I would go a 80% compost and 20% vermiculite mix, if you can afford it. If not, go with however much vermiculite (assuming you can find it) as you can afford, and fill the rest with compost. Plants are amazingly resilient and can really surprise you. They WILL grow in compost. There is no doubting that. They will have a lot of nutrients available as well. If your box is open, earthworms will move into your soil and help with aeration. The compost itself is actually quite good at moisture retention, but if you put some mulch down, that will help retain even more, plus the plants roots can go down and find some moisture in the soil beneath your box, if necessary!

And if you don't like the results this year, add some more vermiculite and maybe even some peat next year. Gardening is more about what works for you than it is strict procedures.

The manure I got for the first beds had quite a few worms in it. They love the garden. I buried some squash & pumpkins in the fall and found this in the spring:

I don't dig down into the beds much because it is thick with worms. I'm hoping they produce some nice fertilizing worm castings for me.