Many people think that it is pretty clear cut as to how deep a container herb garden should be. They just know that the herbs can grow up to twelve inches in the ground and they will be fine. The reality of the matter is a little more complex than that.
The deeper you plant your plants the more roots, you are going to need. Also, the deeper the soil the more water your plants are going to need. So, what is the answer?
One way to find out the depth of the soil in which to plant your seeds is to pick some and dig. This will tell you the depth of the “pot” from where it starts to grow. This is good for starting out with because you will have a very shallow hole with the dirt in. From here you can simply add a little bit of topsoil or compost and start off. You don’t want to use a pot that is too deep or the roots will go too fast.
Another thing you can do is dig a hole that is a couple inches deeper than the plants. Most of the time you can get by with one-inch holes. This still allows room for the roots to spread out but it is deep enough. However, this method does take more time and digging. If your climate is very cold then you may want to consider containers that are deeper as well.
So lets say you know the right depth and want to go with a traditional pot. The problem with traditional pots is that they are not very wide or deep. What you really need is a square or rectangular pot that has wider opening’s and deeper holes. These types of pots work great for the most exotic of plants.
The benefit to square or rectangular pots is that you can place them on top of each other and grow several different kinds of herbs in them at the same time. If you have one plant that needs a lot of sunlight then place that inside the deeper of the two pots. On the flip side, if you have another herb that will require less sunlight than plant those in the outer pot. This way you get the best of both worlds.
Once you decide what type of container and depth you are going to use then you need to figure out how much soil you will need. For herbs like Rosemary, thyme, oregano, basil, dill and lavender the soil level should be about one third the height of the herbs. For other herbs such as parsley, sage, chives, marjoram, basil and even Rosemary you only need about a quarter of an inch of soil. Once you have this you can then go ahead and dig your holes.
It is best to use a shovel to dig the hole and spread the dirt evenly before putting the plant in. Once you have the herbs in place you will want to put them in the holes about a half an inch deep. Then just water them well and you are all set. Now you will be able to enjoy all of your new herb plants and you won’t have to ask yourself “how deep should a herb garden soil be?”
As with most things in life, though, there is more to this question than what you see above. Your herb garden soil will be one of the main factors in whether or not your plants will thrive or fail. You can make your herb garden soil pretty good but it won’t matter if the soil is poor and you won’t have healthy plants. Your soil, and therefore your plants, need rich nutrients to grow and thrive. And you can’t give them anything but the best.
The best way to ensure that your herbs grow healthy and well is to choose healthy soil. This means that your herb garden soil needs to contain plenty of potassium, magnesium, nitrogen, phosphorous, calcium, magnesium and iron. When the soil has these ingredients it is ready for the plant and there is less need for you to worry about “how deep should a herb garden soil be?”
To find out how deep the garden soil should be you’ll need to test it. You can test your soil by breaking it up finely and then breaking up the powder as fine dust. Most of the garden stores sell soil and you can test it in that way, or you can get a tester from the hardware store. Once you’ve tested the soil, let it sit for three months and then re-test it. Most people find that using the same test method about six times helps them narrow down on the depth of their herbs.