What should general PH and nutrient levels be for new planting bed after amendments?

Question

I am planting a salad garden with lettuces, kale, spinach, root crops, pole beans, tomatoes, peppers, and cucumbers. So many different PH level requirements and such for different plants are confusing me because I have grown them all together before successfully. This will be the first time getting a soil test done through the University of Florida this week. I just don't have any idea what to do with the information. After I have added rich compost, worm castings and rock dust to my existing garden bed (4'x12') what levels of nutrients and PH should I aim for overall? Zone 9b, Florida.

Answer 1

You forgot one of the fundamental rules of debugging any system, whether it is a doctor requesting tests on a patient, someone debugging a computer program, or anything else: if you don't know in advance how you are going to use some piece of information, don't waste time and money getting it.

Most plants do fine in a wide range of conditions. I don't see anything in your list which has really "special requirements". A pH round about 6.5, plenty of organic matter, and an adequate water supply is a good starting point for growing most things.

If you don't know why you are applying rock dust or whatever, don't waste time and money on them! In any case, you have got this backwards: you apply rock dust if the soil analysis tells you that you need rock dust, not the other way round. You don't apply it first and then do the analysis to see if it was necessary.

Answer 2

In general you can ignore pH, but if you have extreme pH soil (you will see from wild vegetation) or for few very specific plants. You listed very common vegetables. They are "common" also because they can growth on various type of soil.

For pH, we usually have two listing: pH where the plant growth naturally, or the pH range where the plant can growth. The first more frequent, but often confusing: it just mean that with such pH and condition, the plant is more adapted then other plants, it doesn't mean that it is its preferred pH. This creates a lot of confusion.

In general, pH have two effects: calcium: this is poisonous for many plants (like salt), because it enter easily in the roots instead of other nutrients. Some plants are adapted to calcium (so usually high pH) [like some plant tolerate salt, sometime with same method: you will see calcium or salts pushed out in the leaves]. So often plants with like very high pH, can live without problems with low pH. the second effect it is similar: some nutrients could be more difficult to absorb on high pH (low pH dissolve more nutrients in water).

So what about gardens? Gardens have gardeners: rival plants [usually weeds] are removed, and much more nutrients is delivered in the soil. So often you do no need to care much about pH, but for few plants. Some plants likes very low pH [e.g. blueberries], and so you may see symptoms like lack of nutrients (lack of iron is frequent). In that case you may amend the soil just near such plant (and ev. liquid fertilizer directly in the leaves). Few tomato varieties likes high pH. Also in that case, you can amend soil just for tomatoes. But you get tomatoes anyway. As I say, many vegetables tolerate great variability of pH, especially if you care them (fertilizers).

Warning: many fertilizers/manures are acid, so pH of a garden could be often different of what you have at beginning.

PS: and often optimal growth is good only for commercial plants (more production, but tasteless). A grape vine in very fertile terrain will never produce good wines. A chilli pepper in optimal conditions (and a lot of water) will never produce good chillies. Just plant, and adapt if things are going wrong (and weather will create more variability, so you still need to adapt).