IIRC, the federal Biosolids Rule governs the reuse of sludge in composting operations, and it does list limits for heavy metals. Metals have been considered the top priority thus far, since they do not degrade at all and presumably could build up in soil if compost with high levels of metals were applied over and over. I really don't understand the obsession with toilet bowl cleaner. Most of them are either a strong acid or base, plus surfactants, and sometimes, bleach. Acids and bases are neutralized in the treatment process yielding harmless salts, bleach reacts instantly with organic matter (probably never reaches the plant), and surfactants generally degrade in treatment (although a percentage of some survive). Note, surfactants are also in laundry detergent, dish soap, spray cleaners, toothpaste and shampoo. For safety, I recommend not eating them. :-) The one thing that science (perhaps) hasn't worked out yet is the meaning of the trace (yet non-zero) levels of surfactants, pesticides, and other chemicals that go down the drain, some of which find their way into sludge undegraded. I'm not making a case that this is somehow dangerous, because as far as we know it is not. Yet, as an environmental chemist who has seen the field evolve over the past few decades, I am not arrogant enough to think we know everything yet. :-] I think we should all use fewer chemicals in general (including cleaners), which would reduce the risk (if there is any) at the source. We (the environmental science community) suspect there *is* a risk to aquatic life from surfactants in treated sewage effluent that goes back in the waterways, so I am more worried about that than what's in the sludge. To a certain extent our use of thousands of chemicals daily is a grand experiment.

I guess even in soucal,Mango's are needy care plants for nurseries. I know here in the bay area they never look as good as they did when first brought in. The nurseries usually have a long wait until they flush if foliage is damaged in some way in holding. So,they can look ratty. They are healthy...just waiting until they get coddled at your home. As long as I'm rambling...they also never look as good in a pot as they do in ground. Tough call..in a pot,you can be 100% safe from cold of course,and gophers...but they look so...tree like in ground. In the end, the sweet fruit are worth the effort.

Tony, When you mention your bed depth, do you mean that you have bottoms under the beds, so that they're essentially very large containers, or just that you've put frames on the ground and filled them with soil? If your beds have bottoms under them, so that the roots can only dive two or three feet, that would IMO cause many problems...oh. I see the "sticks and logs". OK. I suspect that that layer has cut off your plants' world at the two or three foot mark, whether you have a bottom on the bed or not. You're effectively container gardening. When you're container gardening, your plants are dependent on you for everything. When you're gardening in the ground, they are much less dependent. In the ground, plants can dive WAY deeper than two or three feet. And they can benefit from the bank of moisture and nutrients down there. Edited to add: Oh, and roots can often go a lot more than two feet wide, too. Lettuces are very shallow-rooted, and their need for nutrients isn't that high. So it's not too much of a surprise that they're doing OK. I'm not at all surprised that your other plants are doing badly. I'm not saying that it was inevitable, but I also don't find it surprising. I would suggest that you fertilize, at the recommended levels, and see what happens. If that works, then that's pretty decent evidence that the soil that you purchased has low fertility. You say that you're going to buy more compost next season. But you succeeded, in the past, on the soil that you already have, right? And you want to avoid outside inputs, right? So why are you getting essentially ALL of your soil as an outside input, instead of using the local soil that was successful for you? If I could wave a magic wand, I would create a three-part experiment on your property: - I'd dig out one of the raised beds, remove that layer of branches and logs, remove the bottom of the bed if it has a bottom, dig a spade depth into the soil below the bed, and re-fill the bed with the purchased soil you've been using. - I'd dig out and clear out and dig below another raised bed in a similar way, but fill it with your own soil, mixed in with a modest amount of certified organic compost, of a brand other than the brand that you've used--or with compost of your own making. - I'd dig a third bed in the ground, digging at least one spade depth and ideally two, mixing in the same modest amount of the compost that you used in the second bed, but not raising it at all. Then next year I'd garden and see which one does better. I suspect that the first bed will do somewhat better than it did this year, the second bed will do fairly well, and the third bed will do fairly well. This year: Fertilize! I know that you hope to avoid fertilizing in the future, but fertilizing is IMO the best way to find out whether your issue is low fertility. Another possibility is water. What is your watering scheme for those beds? Have you tried digging down to see if they're getting wet all the way down? You have no capillary connection with the soil below, because of those logs, so those beds will likely dry out much, MUCH faster than your garden did when you were just gardening in the ground.

Adrienne in Thousand Oaks: Regarding UC Verde Buffalo Grass, we installed it June 2021 so can attest to how it took watering twice a day to establish, then less frequently until we were watering twice a week with good results; I live in Thousand Oaks and were restricted to watering once a week for 15 minutes which was a good soak and it survived the limited watering last summer. When first planted as plugs we had a lot of weeds but it eventually filled in and is very thick. What we don't like is that is it dormant and brown in color from November to March; it has been slowly turning green in the last few weeks now that it is spring. It requires very little mowing, about once a month at most from spring to fall. The only way to buy it in Southern California is from FloraSource Ltd. They ship it as plugs in flats so it is labor intensive to have it installed; cost is twice that of sod.