I can’t stress enough how important the soil is in organic gardening.
The question I get the most is about what kind of soil to use. There are many different types out there so it can be quite confusing. I am going to assume I am talking to organic gardeners. If you are gardening conventionally using synthetic fertilizers the soil is not as important because they use chemicals to feed the plants at an alarmingly high rate. These chemicals wash away and are harmful to the environment. Organic gardening builds the soil that already has the components to do so with the organic material in it.
Whether you are using raised beds or raised mounds the soil used is the same. Growing in containers is a little different and I will address that later. If you are not using raised beds you want to create raised mounds. To do that you would dig down about 6-8″, mix in your good soil and mound it about 12″ to 18″ high just like in raised beds so you have about 18″ of loosened soil to allow for deep roots.
So, what type of soil, is “good soil”? A mix of composted manure and compost from organic matter. You want to use the two types ideally because they have different nutrients. I like to use composted horse manure, cow manure and regular compost. Both types have to be composted long enough to end up looking like a dark rich crumbly soil. Horse manure for example should compost for about 6 months, and there should be no more formed clumps. Regular compost should also be crumbly dirt when used. You can add either of these not totally finished if you put it in 2 to 3 months before you plant. After that time just mix well and it should be ready. You could also use 2/3 compost of any type and 1/3 topsoil on the top. The amount of nutrients will always vary no matter what type of compost or soil used. To know exactly what you’re lacking you can take a sample to the local extension office and have it tested. I have a cheap little tester that tests general fertility and ph . It works well enough for me. Luster Leaf 1880 Rapitest Electronic 4-Way Analyzer I also add in a general organic granular fertilizer Espoma GT8 8-Pound Garden-Tone Plant Food to the entire bed or in each hole when planting according to the directions on the package. This will last about a month and help to start the building of nutrients. I then will use a liquid fish fertilizer the rest of the season. As long as I started with a good soil that is usually all I need. If you can’t find manure or compost in quantity you can use garden soil or topsoil and mix in bagged compost to the top 3 to 6 inches.
A soil like this will only get better and better. As the season goes on if needed I do side dress or fill in with more compost or composted manure. At the end of each season or the beginning of next, after the old crops and debris are removed I fill the beds back up with new. New compost is a must each season.
Where do you get these composts? One way is to find a horse farm if possible, they are usually happy to load up your truck. Make sure to get from the bottom of the pile where the best stuff is. Or you can find a local garden center, landscape company or someone who sells compost or garden soil and have it delivered. The local dumps sometimes have compost from yard debris, trees etc. and it is usually free. Some of that mixed with composted manure is a great blend.
If you can’t find any of that you can use topsoil mixed with as many different bagged composts you can find. You may need to mix in some peat moss depending on the texture. Topsoil alone usually does not have the organic material and nutrients needed. It can also be too heavy which is why you would add the peat moss. Garden soil should be okay to plant in but always ask what is in it so you know if you need to add anything. Bottom line is soil by any name is always different.
For containers you want to use a “potting soil”. It has to say potting soil, not garden soil or topsoil. The reason is in containers the soil has to be able to hold and drain water properly so the mix is important. You will also need to fertilize more since the soil in the pot is all there is to feed the plant and heat and rain will deplete the nutrients.
I hope this article answers most of the soil questions.