There is a never ending debate among gardeners about using topsoil or compost in any garden. Maybe you lean to one side or the other. Or maybe you’re still on the fence. Either way, you have to consider whether there is a difference when working with a raised bed.
Should you treat your raised bed different
You should treat your raised bed different then your other gardens. Raised beds are completely controlled by you. Your gardens that are on the ground are subject to the conditions of the ground. This doesn’t mean you don’t control the ground garden. It just means the ground garden needs different care than your raised bed.
Can I use only compost or topsoil
In your raised bed you can use either topsoil or compost without the other. If you choose to only use topsoil, you need to source it from a nutrient rich location.
Another thing to think about when deciding which one to use is what is contained in each
Topsoil is the top layer of soil. It has been harvested from the ground some where. This means you need to seriously consider where the topsoil comes from. The amount of sticks, minerals, and pH can vary greatly from one topsoil to another.
Topsoil, because it is harvested from the ground, will have seeds in it. The type of seeds can range from weeds and grass to trees.
Topsoil can also be contaminated with herbicides, pesticides, and other toxins. All of this doesn’t mean you can’t get a good topsoil, it just means you have to research what you are buying.
If you put topsoil without compost in your raised bed, you will likely need to add fertilizer. You will also need to check and balance the pH.
Compost by itself is great for raised beds. Compost is not harvested from nature, but instead, is made by adding different nutrient rich, organic material together and allowing it to decompose.
Just like topsoil, though, you can have good and poor quality compost. You should get your compost from a reputable dealer. Many things can be put in compost. Some things put in compost are not healthy.
Even if the compost is made from vegetables, grass, coffee grounds, and other natural material it can still be bad compost. Many seemingly healthy products have a lot of pesticides and herbicides sprayed on them. These toxins will become part of the compost and will be absorbed by your plants in your raised bed.
The best composts are heated to a high enough temperature to stop weeds from germinating. This is a benefit you will enjoy in your raised bed if you use compost only. No weeds will be added to your raised bed by compost that has been heated correctly.
Making your own compost for your raised bed
When making your own compost for your raised bed, you want to use only healthy, nontoxic ingredients.
If you are going to make your own compost, you can use scraps from your own house. This way you know what is going in it. Just don’t put meat, eggs, or bones in it.
Your raised bed needs good organisms living in the soil. You can help your compost along by using a compost starter. Compost starters contain healthy organisms that will decompose the things you add to your compost pile.
Also, you can compost using one of two methods. You can use the cold or hot compost method.
Cold composting takes a lot longer then hot composting. It will take about a year for your cold compost pile to fully break down in your raised bed.
Keep in mind, you don’t want to exceed 160° F or you will also kill the micro organisms that you need for a healthy garden in your raised bed.
Should I mix compost and topsoil
A good solution is to mix compost and topsoil. If you were building your garden on the ground this is the way you would it.
A lot of people recommend a 1:2 ratio, compost to topsoil mixture. This is what a ground garden bed would normally get. Because you are cultivating a raised garden, you can really use any mixture you like. I would recommend, though, using more compost then topsoil in your raised bed.
Your raised bed is not very large and needs as much nutrients as you can supply. A good compost will have more nutrients than topsoil. Topsoil is not completely broken down and will have to decompose more. On the ground this is ok, but with limited space in your raised bed, it is better to have more compost.
You can also mix in some potting soil. Potting soil contains organic material an peat moss. This will enrich your mixture with nutrients. There are different kinds of potting soils for different applications. Make sure you add the kind for the type of plants you will be growing in your raised bed.
Can I add manure to my raised bed?
Manure will add nitrogen and other essential nutrients to your raised bed. It is also a good source of microorganisms that will help keep your raised bed soil healthy. In addition, manure contains a lot of organic matter.
Use manure from herbivores, not carnivores or omnivores. The best manure you can use in your raised garden is cow, horse, chicken, and sheep.
Do plants grow better in topsoil or compost?
It’s not really a question of which is better for growing plants, topsoil or compost. The question you have to ask is, “Do your plants have the nutrients they need?”
You can provide healthy, nutrient rich soil to your plants in your raised bed with topsoil or compost. You just need to support which ever one you choose with the right types of additives. This will ensure that any where there is lack it will be made up by a supporting product.
So, the debate of topsoil vs compost for your raised bed is one you will have to decide for yourself.
There are benefits to using topsoil and compost in your raised bed. Topsoil has a lot of organic matter and will break sown slowly over time. This will provide your raised garden with nutrients for several months.
Compost, if heated correctly, doesn’t have weed seeds that will grow. It is also packed with nutrients that are ready for your plants to use now. This can be beneficial if you are just starting your raised garden.
A good compromise is to mix both of them together. This will give you organic matter that will add nutrients slowly to your raised bed while providing much needed nutrients now.