If the manure was well composted it may not have had as much nutrients as you expected. Peat has practically no nutrients. Perhaps they need feeding.

Another possibility, depending on the permeability of the clay you have, you may have made a basin or bathtub effect which is holding water and is detrimental to the roots. With time, adding amendments will help the clay, which is normally richer than loose topsoil anyway. If the roots can get down into it, they would do better.
Just my thoughts based upon what you wrote.
Bill P.

I agree with Gonefishin about "the bathtub effect". I've seen other people have root rot from that.

But I will also suggest that 50% peat may also be part of the problem. That's a lot of peat! It is acidic IIRC, infertile, and when it dries in the soil, it can be hard to get it wet again. I use it in my potting mix, but never more than about 10-15% of volume and well mixed in.

The manure can also be tricky. The fertility of it depends greatly on the source and the aging. Depending on it's age, it can be hard to mix in well. It can also stay very gloppy-wet.

So, it is possible that you have pockets of manure and peat around your roots making for very uneven root conditions and low pH.

You could use a bulb planter to take a soil sample from around a plant (to see what the soil structure, moisture level, and root penetration is). You could also try using a bulb planter or auger drill to make some holes around the plants and fill them with compost to give the roots a source of balanced nutrients. Finally, foliar spraying and/or compost tea watering might help get the plants jump-started.

Best of luck with the recalcitrant tomatoes!

Thanks much for the replies. I admit - I had no idea... I figured manure and peat would make a good soil when mixed. I've tried this small, patio, garden for a few years now and have never had great results. The soil here was just so rocky and hard to deal with that I finally decided to replace it. I wanted to add humus, but the garden center didn't stock it. So I went with the peat/compost mix. About 600 pounds of it. My bad. Now I know. I did mix it well though.
So - with it being a bit too late this year - come next spring, or this fall, what do I add to the soil to balance it. Humus? Good fertilizer? Top soil?
Today, I mixed in a little gypsum, and a little blood meal into the top inch or so of soil. Then watered with a light fish emulsion fertilizer. My cucumbers seem to have wilted a bit from it, but everything else seems happy so far.

I think first thing I would do is get some slow release fertilizer like Ozmocote 10-10-10 and sprinkle it around the plants. Then get some straw or hay and mulch well. After the plants die in the fall work all the mulch in well and add more to work in before planting.

You could also add green sand now. but that takes time to break down but you can apply directly to the base of the plants without ill effect. another good thing to do is to start a compost pile if you have the room. Let it sit the winter and mix that in during the spring as well.

Bill

If you have them, grass clippings as mulch helps a lot.
So do coffee grounds. Leave the clippings on top of the
soil and mix in well next spring.

If at all possible, take out some of the compost/peat and
try to dig the remainder through the bottom of the 'bathtub'.
Mix it together with the native soil. That will remove
some of the barrier effect.

Many folks mix in fresh amendment every spring (I'm one of
them). Seems to work for me.

i would think that you need actual dirt in your soil...something with a bit of clay content to hold minerals in there a bit.

so..it might be a little painful..but i would add just a little bit of your native soil back into your mix (not the rocks, of course.) reconditioned clay soils are actually some of the most FERTILE soils you can have because clay holds so many nutrients! now, i'm not saying add a lot...but i'd get at least 5 percent back in there. but that's me.

i took a semester of soil and plant nutrition..and you want a lot of organic matter in your soil...but not too much, you also need some clay, sand, and silt as well to have a well balanced soil.

pots are a different story all together because the soil is confined and the drainage has to be fast and excellent or roots would rot and die.

I also have clay soil & have been working over the past 2 years to make it better. I did add humus (from Lowe's-- Home Depot doesn't have it) It does have some sand in it also, which I think helps some for drainage. Also last Fall I tilled in all the dead plants plus LOTS of shredded newspaper (not the colored sheets). I also added some manure & more humus & several tubs of earthworms. The dirt is SO much better this year, but I've heard it takes several years of putting in organic material to get it really good. I mulched the vegetables with shredded newspaper too, plus some hardwood mulch & will till all that in in the fall.Good luck to you!