The 5 Types of Dirt Every Gardener Needs to Know

If you've ever found yourself wondering exactly what the difference is between compost, manure, leaf mold, potting mix, peat moss, soil and so on, you're not alone. These terms get used interchangeably all the time, but each one plays a very different role in the garden. In this video we're going to look at what each of these materials actually is and how you can use them to get the best results. By the end you'll know what to use where so you can build healthier soil and grow happier plants without wasting your time or money. Well, we best dig in then. Let's start at the beginning with soil itself. This divinely delicious dirt is literally the root of all life. It may not look like much, but this is a living, breathing ecosystem made up of mineral particles such as sand, silt and clay, organic matter from dead and decaying plants and animals, air, water and nutrients, as well as most excitingly for us gardeners, a truly vibrant community of living beings. Worms, beetles, bacteria, fungi, all sorts in there. Together this makes a real living ecosystem for our plants to thrive in. Few soils are perfect. Very sandy soils might just drain through too quickly, whereas wet, claggy clay soils will stick to your boots like glue. But every soil will benefit enormously from the addition of organic matter. Organic matter is anything made from once living organisms. It will help to improve your soil's texture while feeding all the life within it, which will then feed your plants. It will help plants to access those nutrients and help your soil cope with extremes of very wet or very dry weather, buffering those extremities. So whether your soil is sandy or very clay, organic matter can really help it. So let's now take a look at the different types of organic matter, such as compost, manure and leaf mold, and how they can come into play. Regular viewers will hear me banging on about compost quite a lot, but that's for a very good reason, and I know that some of you like to sort of play a game and count how many times I say the words like a compost, so we'll run a little counter and we'll see how many times I say it by the end of the video. Compost is one of the very best ways to improve garden soil. Just look at it! This kind of crumbly texture, it reminds me of a delicious yummy chocolate brownie mix. Just yum! Welcome to my compost heap. Now compost is simply organic materials that are broken down. That could include, for example, kitchen waste, coffee grounds, old weeds, trimmings, lawn clippings, as well as say the waste from herbivorous pets and chickens, and all sorts of other ingredients. Through the magic of microbes, fungi and earthworms, these raw materials gradually transform into this beautiful rich earthy smelling goodness. Compost! Compost! Compost! Compost! I like to think of it a bit like a home-cooked meal. It's never going to be really flashy and high-end, but my goodness, it doesn't half make you feel better! Compost is really first rate at improving soil structure, feeding soil organisms, and releasing nutrients for plants to get their teeth into. And it's safe to use anywhere, just leveled onto the soil surface or dug in. I like to spread my compost out as a layer about an inch or so deep, that's up to three centimeters, at least once a year, typically in late autumn or winter, or perhaps in early spring before I get planting. Now what I'm doing here, leaving it on the surface, is creating a mulch. The compost here is a mulch, and what I'm doing is, funnily enough, mulching. Traditionally compost is dug into the soil, but I prefer to spread it over the top like this as a mulch. It saves my back and is a lot less hard work. Not only that, but it's actually better for the soil itself, because you're not digging it up and tearing it away, it's all those lovely kind of fungal structures in there. We're leaving it alone, and then the worms, it gives them something to do as they dig it all in for me over the winter months. And while most of my compost is added in the winter months, I won't shy away from adding it around actively growing crops in the warmer months, when this magical mulch will help to keep the soil a bit cooler and lock in valuable soil moisture. No matter how you use it, compost will help to steadily improve your soil over time. It's one of the most powerful tools any gardener has. Ah, leaf mold! One of the most underrated materials in the garden, in my humble opinion. Now leaf mold is simply rotted down leaves, and that's it. Leaves are relatively high in lignin, which means they rot down a bit slower because it's a tougher material, and this cooler process happens using more fungi rather than bacteria. Leaf mold is incredible at holding on to moisture while boosting beneficial fungal life in the soil. It also helps to create a lovely soft kind of crumbly texture, which is really important because that will help the plant roots to travel more easily through the soil. Now it's not especially rich in nutrients, but that doesn't really matter. For me, leaf mold is more like a soil conditioner rather than, say, a fertilizer. Like compost or manure, I use leaf mold as a mulch around empty beds or actively growing plants whenever I think I need to improve that structure and give plants a bit of a boost. But because it is relatively low in nutrients, it's also really great for making my own seed starting potting mixes. Seedlings don't need much at all in the way of nutrients, so I can use this to make my own and save a bit of money. Rosie, goodness, does anyone else's dog act like a cat instead of chasing them around when they're raking or hoovering? Rosie loves it for some reason. Anyway, the best thing about leaf mold is that it is completely free. Every autumn a whole new bounty of riches rains down from the trees, and all you have to do is collect them to rot down over time and then use in the garden. Next up, manure. Now you'll find some pretty strong opinions about this stuff. The manure that we use in our gardens is from herbivores such as cows, horses, sheep or chickens. Stuff straight from the source is really powerful stuff, full of nitrogen and other nutrients which plants will really flourish on to grow strong. That's all well and good, but really fresh manure is perhaps a little too potent and can risk literally scorching the roots of plants. Fresh manure is a little bit like a toddler, full of potential but absolutely not what you want near your delicate plants. Instead it's best to use something like this stuff here. Now I bought this manure in and it's been stacked for several months to mature, kind of like a nice fine wine, and if you look at it, well it's nice and crumbly, it's dark and you can't really see any of the original bedding materials in there. What we've got here is really aged beautiful stuff, and in fact there's another term for you. This is aged or well-rotted manure, and you'll often hear that term bandied around, well-rotted. In this state, aged or well-rotted manure behaves a lot like compost. It's going to improve our soil structure, it's going to replenish a lot of nutrients in the soil there, it's really lovely rich stuff full of the nutrients plants need to thrive, and I tend to prioritize it around especially hungry plants. Crops like brassica family plants, that's cabbage family, pumpkins and squash, and corn. Now as you may have heard me infusing before, I just love manure. It's really great stuff, but please be careful where you source it from. Some manures may contain traces of persistent herbicides such as amino pyrrolid, I hope I've said that right, which can be in the manures of animals that have grazed either treated pasture or hays that have that herbicide in it. So do ask around or test a little bit of it before using it more widely, because it can really harm sensitive plants such as tomatoes, potatoes and beans. Right, let's on to the next one. Next up, potting mix. Now this is where things can get a little bit confusing. Depending on where you are in the world, you'll know this is potting soil, potting compost or simply compost, but this is a very different beast from the garden compost we looked at earlier. Potting mixes are specially formulated for plants growing in any kind of pot, tray or plug tray for example, and that's because plants in any type of container need something that's nice and light and airy, that retains moisture yet is still free draining. Now it could be tempting to just dig up some soil from the garden and use that instead, but the trouble with soil is that it's quite dense and can kind of compress down in a container, and it will also be quite variable. So a specially formulated potting mix is going to keep plants in so much happier. Potting mixes give optimal conditions and are typically made from a range of ingredients, things such as composted bark, green waste, coir or coconut fiber, sand or grit, perlite, vermiculite and even some added fertilizers. Some mixes also contain peat, but many gardeners now prefer to opt for peat-free mixes because of the impact that extracting peat has on fragile peatland habitat, and I'll talk more on that shortly. Now seedlings need a slightly lower nutrient mix because they're delicate, something like this here, and you can find it sold as a seed starting mix or just a seed compost. More mature plants however go in for the more nutritious stuff like this, but this is often sold as all-purpose potting mix or multi-purpose compost, and it's all-purpose or multi-purpose because it can be used for a range of things. So although this mix is ideal for slightly bigger plants, it's also good for starting seeds if you sieve it or screen it first to give a finer texture. Peat or peat moss has long been used in gardening because it's really great at holding on to moisture, has a lovely fluffy texture and is quite sterile, which means it's a really good base for building upon to make your own potting mix. However, extracting peat isn't great environmentally. Peat bogs are really, really great for storing carbon but also have some quite unique wildlife. So when we extract peat, all that carbon that's locked up is released into the atmosphere and it damages really precious, fragile ecosystems. Far better to just avoid peat if we can and look for potting mixes that say peat-free. Thankfully there are sustainable alternatives to peat, and this is my favorite here, coconut fiber or coir. Now this still has to be shipped and so on, but it's a renewable resource and is much less damaging. It's a byproduct of the coconut industry. Now just like peat, it's lovely and fluffy and loose and quite sterile, and you can use this to create all sorts of potting mixes. My favorite way to use is to mix it with some just bagged all-purpose potting mix and a little bit of perlite to create a more open mix for growing things like peppers, or you could mix it with a compost or leaf mold from your garden to create a lower nutrient mix perfect for seedlings. Our next woody duo are fairly self-explanatory. Now let's start with this, wood chips. Wood chips are just chipped up branches and other small pieces of wood to give, well, this kind of wood chippy texture, and then we've got bark chippings which are arguably more decorative. These are the outer pieces of bark. Both these are not ideal for digging into the soil, and that's because they've got quite a high carbon content, and as the microbes break them down they steal nitrogen from the soil to help with that, and that would deprive plants of that nutrient. The main way I use slightly woodier material like this is on my paths where they help to keep weeds down and stop the paths sort of churning into a muddy mess, and then as they rot down into the soil beneath they'll actually return nutrients that the plants and the surrounding beds can actually tap into as well. I also like to use them around perennial plants like fruit trees and bushes where this will rot down much slower and release nutrients in a much more kind of sustained steady way, which is perfect for these slightly slower growers, and as it rots down it will also really help to improve the kind of fungal life in the soil which in turn will support our plants. And wood chips are a great material for layering with greener, more nitrogen-rich materials or manures to create a powerhouse of compost, and you can learn more about that in my recent visit to legendary no-dig gardener Charles Dowding, and I will link to that video down below. So let's sum up the differences between all these different materials so you can choose the right one for the right job. Understanding the differences between these materials will help you to unlock so much potential from your garden. Not only will it help you to build healthier soil, it will also help you to use your resources more wisely. How satisfying! And talking of satisfaction, don't forget to nurture yourself too. Get your muddy mitts on a completely free abridged version of my book simply by signing up for our video newsletter which is also free. You'll get more than 100 pages of practical advice, projects and inspiration to help you grow more and grow better. Just follow the QR code or the link over here, and I will catch you next time.