A blog that calls itself “Dirt” needs at least one post on the subject, don’t you think? So this post is about just that: dirt.
Dirt/soil is the most basic and also one of the most important building blocks of your yard or garden. It doesn’t just hold the plants in place; it gives them the nutrients they need, absorbs and collects and it protects the root system of the plant from sun and cold. Most plants grow in some type of soil. The exceptions to this rule are air plants, such as orchids that absorb nutrients through the leaves; roots are used as anchors only, usually to other plants. Some water plants do not need to root in soil, but get their food from the water. Or one of my favorites; plants like the Venus Flytrap that survive in very poor nutrient soil or watery bogs with little to no soil by ‘catching’ their food in the form of insects. Hydroponics, plants grown in controlled conditions in nutrient rich water, is another form of soil-less growth.
For most plants you buy in your local nursery though, they are going to need dirt. The nursery tag on the plant should tell you what type of soil it prefers. Like almost all living things; plants need air, light, water and food to thrive and grow. Good soil is one of the most important steps in the health and success of a plant. Some plants will not only do poorly in the wrong soil type, they will simply not survive.
This doesn’t mean that if the plant you want to grow doesn’t match the soil type in your yard, it is automatically off limits to you. It most cases, it simply means you’re going to have to adjust or amend your soil to meet that plant’s growing requirements.
There are three basic soil types: Sand, silt and clay. Each of these soil types has a different particle size and holds water and nutrients in a different way. If you aren’t sure what you have in your yard, one of the easiest ways to test it is by feel. Pick up a handful of wet soil and try to form it into a ball in your hand. If the ball falls apart easily, you have a lot of sand. If it forms a loose ball, it’s silt. If it forms a semi-solid, sticky ball, you have clay. Of course, I’m over-simplifying a bit here, but this is after all, a blog post and not a book. Give or take specific mineral content, the vast majority of plants prefer a moderate silt-type soil. If you have one of the other types, your goal will be to amend it until it resembles silt as much as possible. This usually means adding some form of organic matter to the soil.
Sand– Has a large particle size, feels rough when rubbed between your fingers, but doesn’t hold nutrients well. Sand usually provides good water drainage.
Silt– Has a moderate particle size, feels powdery when dry/smooth when wet, but not sticky. It holds nutrients and water well; it’s usually the preferred growing medium for the majority of plants.
Clay– Has a small particle size. It can turn to a brick when dry and is sticky when wet. Soils with high clay content are called heavy soils. Clay can hold a lot of nutrients, but drainage and air circulation is often poor.
There are many options when it comes to soil amendments. It’s not recommended that you try to adjust your sand or clay soil by simply adding clay to sand or sand to clay. This is a recipe for cement, not so great for plants. Your best bet is to add organic matter, or some form of man made additive or fertilizer. You can buy all sorts of things to improve your soil at your local nursery or garden center such as bags of humus, peat, vermiculite, chemical and natural fertilizers and so forth. I stay away from the majority of these for two reasons: 1) They are expensive and 2) I don’t like chemicals on my lawn/plants/food, etc. I prefer to use natural materials and make my own compost. I’ll write a more in depth post on the compost subject later, but for now I’ll just say this can include leaves, yard clippings, newspaper, vegetable scraps, etc. You break them down in a compost pile or drum, bucket, bin, what have you and just mix them directly in with your soil.
Another option if your soil isn’t quite perfect is to grow on top of it rather than in it. By this, I mean building raised beds, using planters, pots, or some other method of getting your plants out of your native dirt and in to purchased potting soil or garden soil instead. More expensive than composting, but often a lot less work and can require a great deal less patience. I’ll also try and revisit this subject later, as I’ve spent a good deal of time building raised planting beds around our yard.
Once you have the consistency of your soil right, meaning you’ve added material to it so that your clay or sand feels more like silt, you’ll then need to adjust the content for nutrients such as nitrogen, phosphorus and potassium depending on the plant’s individual needs. (Yet another subject that could be addressed at length…) Commercial soil additives will usually list these nutrients on the bag and their concentrations in percentage form. Nitrogen helps leaf growth and dark green color, Phosphorus encourages plant cell division, flower and seed formation, root growth and protects plants from disease. Potassium increases plant’s disease resistance, encourages root growth and is needed for making chlorophyll. You can buy soil testers to test the amount of specific nutrients in your soil if you feel your plants are suffering from a lack of one of the above. Testers can also help you with adjust soil Ph, which is especially important to the health and production of some plant types.
A Ph range of 4-9 is about the limit of plant growth. The Ph scale runs from 0.0 being the most acidic, to 14 being the most alkaline. You don’t need to be a chemist to adjust soil Ph. An application of lime and fertilizer will lower the Ph of acid soils, or if your soil is too alkaline you can apply sulfur to lower the Ph. Before home soil tests were readily available, some farmers would actually taste their dirt to see whether it was ‘sweet’ or ‘sour’. If it had a soap taste, they knew there was some lime in it and if it was sour, they knew it was acidic. Sand and loam require less lime/sulfur to raise or lower Ph than is needed to adjust clay.
Those are the basics on soil/dirt. As I said a couple of times above, I’ll expand later on several of the points I touched on in this post; this gave me sort of a jumping off point to start from. For those of you that have clay soil, keep reading… it’s one of my favorite gripes- er… subjects. I’m sure to have lots more to say on coping with it later.