The Compost Manifesto

The majestic Front Range of the Balcones Escarpment (an unfortunate delivery of SAWS biosolid compost).

I have a confession, I completely suck at making compost. No, it’s true. There’s so much lore about getting the greens and browns and whatever else just right, I get lost immediately. Compost teas, worm bins… with the amount of content on social media and blogs about these practices, you’d be forgiven for thinking you need a master’s in compostology to even think about starting a vegetable garden. But there’s good news for the compost illiterates of the world, you don’t need to know how to make compost in order to use it effectively. It’s true that there’s a whole world of compost to get lost in and you can save some coin if you learn to make it yourself, but there’s really only a few basics you need to know in order to harness its power effectively.

Organic is mandatory

If you’re a human concerned about your health and the health of the planet in the year 2024, you’ve probably read something about per- and polyfluoroalkyl substances (PFAS), the so-called “Forever Chemicals”. These have unfortunately become quite ubiquitous and are currently thought to be linked to human health issues like certain cancers and reproductive problems. While these are found almost everywhere humans live these days, they are most likely to be absorbed into your body when you eat or drink contaminated food or water.

What does this have to do with compost? Well, hypothetically, if you were a brand new market gardener starting a garden on a budget, you might be attracted by a very affordable type of compost made out of what are called “biosolids”. In addition to being affordable, this has the added attraction to the idealistic, well read and naive gardener of “closing the loop” by reusing human waste because biosolid compost is essentially made out of treated sewage. Anyone who has read or heard of one of the founding texts of organic farming, “The Soil and Health” by Sir Albert Howard, knows that reclaiming human waste can be an essential practice for helping maintain soil health. When taking from the Earth, we need to add back what we’ve taken out in order to continue producing food, and it stands to reason that reusing that which passes through our bodies is a great way to do that. What the naive gardener might not have understood fully at the time is that the world has moved on since the days of Sir Albert, and in a very grim direction.

While biosolid compost is technically safe to use (modern composting methods are quite advanced and kill off any harmful bacteria etc that would be present in raw sewage), it turns out there are plenty of things in biosolids that are in fact quite harmful to human health and aren’t tested for at all, apparently on the logic that what we don’t know can’t hurt us. Since PFAS are ubiquitous and sewer systems capture so much of an urban area’s waste products of all types, biosolids wind up being absolutely soaked with PFAS. Biosolids as a compost feed stock are in fact a prohibited practice in any organic certification, and for good reason!

So, that’s all pretty depressing, but what does this mean for the gardener? How can you know what’s safe to use? The best rule of thumb would be to stick with a certified organic product, even if you’re not planning on being fully organic. This is the only way I’m aware of to keep PFAS and other such chemicals out of your garden. Certified organic compost is certainly available from a retailer near you and may use feed stocks such as animal manure, green waste from municipal composting programs, recycled growing media from mushroom farms, etc. I even saw something advertised once called “molasses compost” (I still don’t know what that is).

We’ve personally had a lot of success this autumn using green waste compost made from all of the items San Antonio residents put into the green curbside compost bins, including leaves, kitchen scraps etc. This is, in my view, the second best way to “close the loop” and tap into the endless stream of urban waste products since utilizing human waste is no longer a safe option. But whatever it’s made from, buy organic!

Do not dig your compost into the soil

This is a topic we’ll revisit in a future blog post on our growing methods, but please put down the digging fork. Throw your rototiller into the Gulf of Mexico. Turn your plowshares back into swords. Compost does not need to be tilled or dug into the soil in any way!! Double digging, triple digging, it’s all a massive waste of time. When building a new vegetable bed, simply dump down a solid three or four inches of compost as a surface mulch. That’s it! Nature will bring that compost goodness into the soil for you, no digging required. Not only does this cut down on labor, but also boosts the water retention, drainage and cuts down on weeding. Compost can also be used a surface mulch for things like fruit trees, berry bushes, or anything else that produces an edible fruit. Which brings me to my next point…

Compost isn’t about fertilizing

One huge misconception about compost is that it’s about fertilizing the soil. This sounds logical but it really isn’t what’s going on. Thinking of compost as fertilizer is a byproduct of the legacy of industrial farming. With the advent of scientific farming, soil and plant life was reduced to the “NPK” formula, or nitrogen, phosphorus and potassium, three elements that have been identified as being the keys to plant growth. When chemical fertilizers came on the scene in the 20th century, they were sold according to their NPK ratio. Need more N than P and K for whatever you’re growing? Here’s a chemical fertilizer with an NPK of 2-1-1 that will do the trick, problem solved. While the importance of NPK to plant growth is literally true, as usual with conventional ag numbers don’t tell the whole story. For plants to thrive, and particularly if they are going to thrive in adverse conditions or resist pests and disease, they need things besides NPK. Compost contains things like trace elements that are helpful. But the main thing is the microbial life good compost has in it. When this is added to the soil, it give a shot in the arm to the life of the soil, which in turn build the mycorrhizal fungi networks that boost plant growth. Plants are alive in ways that we are just beginning to understand, and building soil health is the best way of building pant health, which goes so far beyond NPK.

Beware of gimmicks

As discussed above, there’s a lot of types of compost. There’s worm bins. There’s compost teas. The list goes on and on. I’m not here to debunk anyone or throw shade. I have no doubt at all that many of those practices work. But so often in organic gardening I see things get too complicated for the average gardener to understand and implement. The danger of this is that the more you focus on these gimmicky type things, the less you’re focusing on the actual garden, because the garden is the place that your fertility is really being created. If you’ve got a system that works, by all means go for it. But my advice would be to cut out all the extraneous things in the world of fertility amendments and stick to basics. Get organic compost, put on ground. The formula could not be any simpler and it gets results.

Ornamental plants do not need compost (probably)

Over the years I’ve heard lots of odd comments about folks who say their soil is bad so they can’t grow native plants, or trees or what have you. They might mention that they want to “fertilize” the area with compost to improve it before they plant. One wonders if this is another untruth told by landscapers selling their services. Or perhaps just another artificial barrier folks throw up so they can justify not doing anything (too cynical? Sorry). Now, their soil may indeed be quite degraded, in fact it probably is. But that doesn’t mean you need to import thousands of dollars of compost to have a beautiful garden. While vegetables generally do need compost to thrive, many native plants are adapted to poor soil conditions. In fact, rich soil can be a detriment to the establishment of wildflower meadows, which tend to thrive most in degraded areas where the weeds can’t compete. All an ornamental bed needs as far as organic matter goes is a health dose of woodchip mulch at the time of planting. After that, nature will take care of the rest through the natural processes of decay. Don’t overthink it!