maintenance amendment for me (fertile clay soil) is always dried leaves from previous fall. for tomatoes, it is best to use them as mulch, after mid-June, when the soil has warmed up. Worms will pull them in over the next months.

Compost. Lots of quality compost. Anything else depends on your soil test results.

Dave

Agree with previous posters, I'll add that anything organic, grass clippings, leaves, etc. etc. is good. May take a while to break down, but "a garden is a work in progress," take the long view.

Thanks so much!

Once all my garden is all up and growing, and the soil is plenty warmed up, I mulch everything really well with ground leaves collected from the previous fall and winter. By the next spring, that mulch is very broken down and can just be stirred into the soil when preparing seed beds with some added compost. I'm already preparing for piling on lots of mulch around tomatoes, peppers, and other growing things.

see, the problem with compost is the following. My soil was P-free (7ppm). Three years of compost, and it is at 80 ppm, well above recommended maximum. When P is that high it can, for example, interfere with Fe absorption. The same for K, which started high, and Ca and Mg, which started very high.

So I prefer to use local leaves. They don't really have a lot of nutrients, as trees pull back whatever was valuable, but they generate a large amount of soil turning and earthworm castings. Plus they mulch, although shifting large leaves can and do smother small seedlings. They are free, too. I add urea as needed, always, as well as chunks of rotten wood to keep up the fungal population.

I agree. Throwing in piles of organic matter without knowing your soil's composition nor the composition of the inputs is a gamble. I have high levels of Potassium and Phosphorous in my soil already so I need to minimize compost and chicken manure. I try to only replace what is lost each year. A soil test every other year lets me know how I'm doing. My organic matter % hovers around 6.3 - 6.5% which is quite adequate.