Thank you everyone for your posts:
James: You could be quite right – much of the soil available to me is heavily contaminated with invasive weeds which I’m trying to out-compete in situ and not inadvertently spread. The composted horse manure is relatively light and easy to work with. I’m not having any difficulty getting the seeds to germinate, but in the past when I used just potting soil, the seedlings just sat there and did nothing. Since using my own mix underneath seed starting soil, the plants have generally grown well and gotten large enough in their little paper pots that I could drop the pots right into holes in the garden. I’m generally only starting a small number of any particular plant, so not having to do multiple transplanting steps combined with not disturbing the roots when they go into the garden has balanced the up-front effort.
R. Steel: I think that you are correct and that I was too generous with the wood ash. I generally water seedlings with our house water which is a deep well, heavily mineralized and with lots of calcium – in other words, probably basic? I will switch to rain water for the tomatoes in particular. I’ve started kohlrabi, cabbage, and lettuces this spring which did well, but they were mostly started with last year’s bin of mixed soil and in retrospect I’m sure I added less ash.
The plants do get supplemental light. I’ve got 48” LED plant lights that run from 5:30 am to 10 am and again from 4 pm to 9:30 pm and which I raise out of the way during the day if it’s not too dull. Unless the break is an issue (could the plants think it’s two days?) the over-all hours of sunlight should be OK. On heavily overcast days I often push the timer override button and leave the lights on.
I admit I feel like a total failure in the composting business. My current compost bins are heavily shaded and don’t have a ready water source. The additions tend to come in fits and starts resulting in compost that sits there doing a very slow rot. Our farm tends to have too much nitrogen (chicken shit and fresh greens) and the only plentiful browns are wood chips or shavings. I have difficulty getting the moisture level correct consistently through it and don’t have a system set up where I can turn it by shovelling from one bin to the next. This results in compost which is high in residual woody material and probably still too high in nitrogen. Last year, I started using organic coffee sacks in the brooder in an effort to remove the wood shaving issue from composting. (Once out of the brooder, all our chickens are pastured so the field worms are responsible for processing the manure in situ.) The downside is that until those sacks break down there isn’t really any easy way in the current location to turn the pile. I try to use the fresh greens to attract the local worms but a warmer location would really help. Thus, the suggestion of using worm castings or worm tea isn’t easily available right away.
William: Herbicide residue is a fear, but my source of horse poop also uses it on her garden and she claims her plants have all been fine. The coffee sacks I’ve been using are supposed to be organic, but one can’t always be sure how good foreign controls are. Considering the tomatoes are doing very poorly, but cabbage and lettuce family crops have been happier, I’m thinking pH and nitrogen are probably larger issues.
Walt: I would sooooo…. like to have even a small greenhouse. In the short term, I’ve reseeded all the tomatoes using a commercial potting soil (which unfortunately has a slow release fertilizer in it – so much for my permaculture principles) because time is running out.
No one has suggested I’m dealing with some sort of disease process which is a relief. The soil I have mixed can still be used to top-dress plants that need a boost or are heavy feeders but I may still try to extend it with a low nitrogen acidic material. I have tended to think of tomatoes as heavy feeders, but maybe that is really only true once they start producing fruit. I will make more of an effort to move my compost to a warmer location and do more research on worms. I’ve tried to do some research on soil testing. (https://www.gardenmyths.com/soil-ph-testers-accurate/
) Our soil has been highly disturbed over its short and long term history, so I’m not convinced any test will be accurate over a meter or two of distance so commercial testing isn’t a viable option. I will search the permie’s posts on the subject. I do think a good quality pH tester might help me, but I’ll need some sort of test for nitrogen that’s easy to repeat often as even within a single compost bin I suspect it varies considerably.