The Square Foot Gardening folks might tell you to mix your peat moss and compost with another part vermiculite and you're good to go. The lasagna gardeners might tell you to layer your peat most, compost, and any other organic material you may have and plant your garden in that.
If you don't want to buy anything, and you're set on planting in pots, I would suggest mixing your peat moss and compost together and adding some of your clay soil as well.
Better still, if you can plant in the ground, don't disparage clay soil. It has advantages and disadvantages but certainly can be made into a fine growing medium with the addition of things like... oh... uhhhh... hmmmm... peat moss and compost for example. Rumor has it you have some of that. All things being equal, veggies do better in the ground than in pots, assuming you have a suitable space.

Also, don't worry too much about pillbugs and millipedes in your soil. They don't bother growing plants much, and they'd make a b-line to your compost-filled pots anyway.

I would be very careful with city compost. They use a lot of diseased material from downed trees and you also don't know if pesticides were used on the materials collected for composting.
I tried it once and had insects and invasive weeds I never had before...it made for a disastrous season!
Now I buy worm castings from a local worm distributor and it's the best soil!

Hi tcstoehr,
Thanks for your suggestions. I am planning to plant some Okra, Tomatoes, carrots and Radishes in my ground. But I was really worried about the bugs, As you say will give a try. I just spoke to my gardener about the bugs. He also said that he'll add some pestiside that will kill these bugs. BTW when you say organic material what do you mean by this. The compost i made at home is organic as per my knowledge. Or are you talking about something else? I do have some worm castings from my worm bin. I this enough?

Re: "Organic material" refers to decomposed leaves, grass clippings, weeds (without seeds), anything organic and natural, not synthetic or man made. It would be best if your gardener avoided most pesticides--since you are growing for the kitchen table. Ask him if he has an "organic" solution--in this case, organic would refer to non-synthetic, man-made chemical pesticides.

Here is a link that might be useful: HarvestToTable.com

Thanks Stephen. This is what i was thinking..

I have a bunch of raised beds made of peat moss, compost, and some composted sheep manure.

They grow well, especially my tomatoes. The strawberries do very well in it too.

You can grow veggies in containers using the mix you listed, but drainage and the resulting low oxygen in the root area may produce sub par performance from the plants.

Growing in a container is *not* the same as growing in a raised bed. The raised bed is in contact with the earth which makes all the difference in the world in terms of drainage and not having an anerobic, water saturated layer toward the bottom of the container.

If you were to cut the bottom off the containers such that soil contacted the earth the mix would work just fine. Alternately you can shove a wick into the drain hole and let it hang in the air. This will pull the excess water at the bottom (the perched water table) out of the container.

If will still likely work, but you wouldn't be the first to express disappointment at how a fine particled, heavy mix like that does in a closed container.

I'm not a big fan of peat moss either. I'd suggest you just amend the soil you have with the other organic matter you have (all that compost) and leave the peat moss out of it. If you have a large enough area in beds that the peat would be "diluted" a good bit by the composts, it wouldn't hurt to use it then. I wouldn't use it in pots though. Like was already suggested, mix that compost with some of your native soil and it'd be best. The insects will definitely find your pots eventually anyway.

I don't much like peat because it's "feast or famine" ~ either really soggy wet or so dry you can barely wet it again. When it's that wet, it takes forever to dry out and when it's completely dry the water just runs off it instead of soaking in. If it's diluted enough by the compost, that wouldn't be so much of a concern.

The problem i have with peat moss (besides the limited supply we're mining out) is it's just useless besides it's water holding capacity.

It does nothing for nutrient holding/exchange. You can get a similar water-holding effect from clay along with an outstanding nutrient holding/exchange capacity.

Clay gets a bad rap, but it's REALLY good stuff as long as it's not all hardpan/compacted, wet all the time, or extremely fine to the point of having little soil structure.

Have you priced vermiculite lately? Because of the asbestos issue, vermiculite prices have skyrocketed lately because they either have to put it through a process to remove the asbestos or get it from a mine that doesn't have it, which is hard to find. So vermiculite now costs $37 for a 3.5 cubic foot bag, way to expensive to use as a soil amendment. I just use it for seed starting mixes. You might be able to find some stuff that's been laying around that has asbestos in it cheap though.

I don't know anyone growing with vermiculite - it holds way too much water and no air. The only application I've seen is to cut bulbs into quarters and hold them in vermiculite for 4-6 weeks until they sprout. I cant find it used anywhere at any nursery. Everyone is using perlite. That's bc it holds both air and water. I knew there was a reason I couldn't find it. Plus we are switching to coconut coir instead of peat moss, too many environmental issues. I would plant in compost. Last year I ended up planting in straight compost some root bound plants and they took off. Normally I would never do that bc it's too gooey, but these poor plants needed a break. For starts I would use Miracle Gro. Just my choice. I don't like Pro Mix

I start all plants in ProMix. I’ve looked at other potting mixes and none come close. I wish it was cheap enough to grow everything in but I can barely justify 10 bales every year for getting plants to 4” pots. For larger pots I mix in perlite and even using parboiled rice hulls this year.

But getting back to OP, do you have an analysis on the municipal compost? It can vary widely but many municipalities provide it at no extra cost to you. And don’t worry about a pesticide residues test; get levels of heavy metals. Those are more likely to find a way into the municipal waste and they pose the greater health hazard. The major aspects of their analysis should include organic matter, pH, Calcium, Magnesium,Nitrogen, Phosphorus, Potassium and Sulfur. Any extreme levels would indicate a need to dilute or adjust mix formula.

All aside the compost is probably right at pH of 7.0 so adding peat moss in addition to perlite to loosen it is a good idea. I would never add soil to any potting mix. If you want weight in he pots add up to 10% purified sand. But you will likely be lacking in most major nutrients, especially nitrogen, in a high organic matter mix. You could add composted manure or fertilizer to bring nutrients into balance. Try to keep all additions as sterile as possible. If your “Compost” is just from a cull pile you would be better off to omit it.

The OP was 9 years ago, but it would be nice to hear how it turned out!

My sister grows tomatoes, salad greens, and herbs in containers filled with her own kitchen-scraps-and-autumn-leaf compost and everything grows great. Luckily she never heard it was a bad idea s she just did it.

It’s just impossible to predict what could go wrong in many instances where people have had good results growing anything anywhere but things do go wrong and then you can only say “I’ll never do that again”.

One researcher looking into levels of compost to use reported declines in crop performance when using compost at levels above 50 cu. yards per acre. That is a level of compost less than 1/2” covering the soil surface prior to incorporating it. So when you try to grow crops in extremely high levels of any compost you run a certain risk of setbacks.

Compost and peat moss don't offer the physical support a plant will need. They're pretty fluffy. So the seedlings will grow fine in them, but they may end up growing horizontal. That may not bother you, and you can always stake them up. I always add some soil to my DIY planting mix. That improves the support offered by the mix. I always sterilize the mix before I use it.

Wow so many different choices to planting in pots and adding soil amendments It’s mind boggling what to do..Ues a I agree totally on the raised beds 🆚 pots..I started with fiber pits this year and want to save the dirt for next year I guess I’ll add my Tomato pots dirt to the raised bed for other veggies with Compost next year and start the Tomato’s next year in new potting soil mix with compost and a little bit of Worm Castings some the price of a 10lb bag is thru the roof these days This is May 30, 2020 I ran into this old post trying to figure out what to do with renewing my Soil of my Tomatoes 5 of them in 15 gallon fiber pot’s Only to learn I can’t reuse any of the Tomatoes dirt again for 2 Years OUCH!! This is going to be expensive growMing Tomatoes in fiber pots I took them out of the raised bed this year Because in 2019 we got so much rain the Tomatoes got diseases and died I even planted my entire garden this year from seed because of that bad season..I wish I could find a cheaper way to reuse the dirt from the tomatoes

What if I use the Tomatoes dirt in the fiber pots with fresh compost and grow Kale or Collards etc. In them over the fall and winter or Spinach Lettuce etc. Could I then reuse the soil for the tomatoes by adding a good Compost to the soil with some worm castings??

Thx for any advice if anyone is still following this OP

God Bless & Take Care Sheila

She’s- I’m not really sure about container gardening but I did read that tomatoes do not like to be rotated... they prefer to grow in the same spot year after year. Why can you not use the same soil?