5 Common Gardening Practices That Can Kill Your Soil

Welcome back casual gardeners. What a cold, wet, rainy day it is today. It's spring in the garden. In fact, today is Easter Sunday. I've been thinking about how there are so many things that we do in our gardens that can actually kill our soil. Soil is perhaps one of the most important things that we have going on in our gardens. It would be a shame if something happened to it. Your soil is alive. And just like you and I, your soil needs to breathe. You can't do that if it's underwater. It's important to water our gardens and to make sure our soil does not dry out. But it's equally important to make sure that we don't overwater our gardens. An overwatered garden doesn't have those essential air pockets in the soil matrix that the soil organisms need to have access to oxygen. And without access to oxygen, your soil will die back, not completely. The anaerobic organisms will take over. You'll start to smell pretty rotten. Your soil organisms aren't the only things in your garden that need to breathe. Your plant roots, even though they're underground, have to have access to oxygen at all times in order to function adequately and keep from dying off. If your plant roots die off, your garden plants die off. And then, well, you've got nothing. Just a muddy mess. Raised beds might need to be watered a little bit more often than in-ground beds. Container gardens might need to be watered more often than raised beds. Containers with larger plants on hotter days are going to need water more often than containers on cooler days with smaller plants. It's generally better to water less frequently and more deeply. And drip irrigation is just the way to go if you can do it. Compost and manure can be a really important and helpful part of a garden and can really do a lot to help the soil. But they do have a dark side. Manure and compost can be additional sources of salt, which means that if you add too much manure or too much compost, you can actually tip your balance in your soil, in your garden, to high salinity. And you can start causing osmotic stress to your soil organisms and to the roots of the plants in your garden. Osmotic stress will keep your plants from being able to take up the nutrients that they need from the soil because they just can't absorb fluids anymore. So it's kind of a big deal. I was surprised to find out that compost is salty. How is that? Compost is broken down and concentrated plant matter. And as we concentrate the plant matter, we're concentrating the salts in the plant matter that are left behind as the carbon kind of oxidizes and we lose some of that carbon. And those concentrated salts are being added back into our soil when we add the compost to our soil. And I'm not saying that all salts are bad. Some of those salts are really important. So this is just a case of moderation. You don't want to add so much compost or so much manure that you oversalt your soil. Now, not all manure is created equally either. Generally, the manure of birds and reptiles is going to be very high in salt because they pee and poop all in one. While the manure of mammals is going to be lower in salt. Carnivores are going to have saltier poop than herbivores. And the least salty poop of all would be bunny poop. As long as we keep that in mind and use our compost and manure in moderation, they can continue to be an essential part of feeding our garden soil without killing it. If you live in a rainy part of the world, this is of course not going to be an issue to you because you have so much water moving through your soil and washing out that salt that you you might actually feel inclined to add extra salt. But if you live in an arid environment like mine, that salt becomes an issue very quickly. In an arid environment like most of Utah, one secret to avoiding adding too much salt to your garden is to pop your manure or your compost on top of your bed before the wettest time of the year. So here that would be winter. We get most of our precipitation in the form of snow. So in the fall, when we're putting our garden beds to bed, that is the ideal time to add your compost and your manure because then as the rain and snow falls on it and melts through it, it will carry away excess salts and leave you ready to go the following spring. Using synthetic fertilizers exclusively in your garden is a really great way to kill your soil. Synthetic fertilizers are a great source of macronutrients. You can get fertilizers with micronutrients and I'm not saying you shouldn't use them. I'm not an organic gardener and I'm not going to yell at you if you're not an organic gardener. But there is something really, really essential to the soil that you just cannot add with synthetic fertilizers and that is organic matter. Healthy soil needs to have at least two percent to five percent organic matter in order to hold the water and nutrients that your plants need and that the soil organisms need. And the trouble with relying exclusively on synthetic fertilizer is that as the organic matter in your soil degrades and is used up and isn't replaced, your organic matter content is going to drop. As your organic matter content drops, you're going to find that you need to add more and more fertilizer over time to get the same benefit that you used to with less fertilizer and eventually you're going to get to a point where you just have to move the whole garden because the soil there just isn't good anymore. You can use synthetic fertilizer as a part of a healthy and productive garden without killing your soil as long as you do not rely exclusively on synthetic fertilizer for the fertility of your soil. Make sure that you're adding organic content in some form, whether it's compost or leaves in the fall or bagged soil amendments specifically for the purpose. As long as you're putting back that organic material that is being depleted over time, you can use all the synthetic fertilizers you want. If you rely exclusively on synthetic fertilizers, you will kill your soil. Excessive tillage is another really good way to kill your soil and I'm going to be really careful to use the word excessive tillage here because there is some tillage sometimes that can actually be beneficial. You can use tillage to incorporate amendments into the soil. You can use tillage to control certain pests. For example, tilling your garden bed in the fall will help expose grasshopper eggs over the winter and reduce grasshopper pressure the following year. So tilling is not all bad. I'm not a no-till gardener. I'm a low-till gardener and I'm not going to yell at anybody who tills, but tilling can present its own special set of problems if taken to an excess or if done the wrong time of year. Soil naturally forms something called an aggregate and that is a clump of clay and sand and silt and organic material that gives it a less uniform texture and the reason that's a good thing is that those soil aggregates are what allows for air pockets that provide oxygen for the roots and the soil organisms and they also allow for adsorption of nutrients into the aggregate so that the nutrients are retained instead of just washing through the soil and into the surrounding terrain and not being available for your plants anymore. When we till, no matter how careful we are, we're breaking up some of those soil aggregates. The more we till, the more damage we will do and you eventually wind up with something that is either hard pan or just has no structure to it at all and you're just letting your plants down, man. You've killed your soil. Tilling can also chop up mycorrhizal networks. So these are the white fibers of fungus that extend under the soil. Sometimes we get mushrooms out of them and that's nice. Some of those mycorrhizal fungi are extremely beneficial to the plants in our gardens and can extend their ability to find and recover nutrients from the soil. You can kill your soil with mulch. Specifically, you can kill your soil with too much mulch. Now, I love using mulch in my garden and I'm not going to stop using mulch in my garden and I'm not telling you you shouldn't use mulch in your garden. Whether you use mulch in your pathways or whether you use mulch in your garden beds to help control weeds and retain moisture, it can be an essential and beneficial part of a garden. It can add organic matter back into your soil and it can help foster life in the soil. However, taken to an excess, mulch can also kill your soil. Mulch can be a lovely warm blanket for your soil and also keep it cool in the summer. But if you put your mulch on too thick, so this fine mulch I would do two or three inches deep at maximum. If you have more coarse mulch, you can get away with maybe five or six inch deep mulch. If you get it too deep, you're eventually going to cut off gas exchange between the atmosphere and the soil and you're going to start to suffocate your soil just as you would with overwatering. We automatically think of something like these wood chips or leaves or organic material when we think mulch, but that's not the only mulch. Plastic membranes are often used as mulch. Weed barriers are technically a type of mulch. And we know that there is research that shows that both of those types of mulch can have deadly effects on the soil. So make sure you're using mulch in your garden conscientiously so that you can help your soil instead of killing it. I hope you recognize that every single one of the gardening practices that I talked about in this video are actually really good for the garden, as long as you do them conscientiously. And I hope I don't scare you away from, you know, actually watering your garden or taking advantage of mulch in your pathways around your garden beds. Don't be afraid to experiment in your garden. The wonderful thing about gardening is that most of the time a mistake just means we do without for this season and we try again next season. There aren't a lot of horrible world-ending mistakes you can make in your gardening practices and I hope that you are open to experimentation and playing and having fun in your garden. Hope you all had a happy Easter. Thank you for joining me here in my garden. I hope you have a wonderful time on your own.