When you grow plants of any kind, your success starts with the soil. That is especially true of vegetables, where success is measured by the amount of food you produce. But how to you know what is the best soil type for vegetables?
There is no such thing as a perfect soil for everything. Different plants have different requirements. Before you invest in your plants — seeds or starters — you’ll want to have an idea of what kind of soil you have and what kind of soil you need.
The three basic kinds of soil are clay, silt, and sand. Clay is the densest soil type, comprised of very fine particles. Sand is on the other end of the spectrum in terms of particle size. It has the biggest, and if you’ve been to the beach you know that it’s hard to bunch it up and keep it that way. Silt is in the middle in terms of particle size. Combine them all in equal parts and you get loam.
If the soil you start with isn’t ideal, you can improve it by adding things to balance out its deficiencies. To do that, however, you need to know which soils are best to grow vegetables in.
We created this guide to help you get started. We hope that you find it handy and wish you the best of luck in growing your own food.
As a side note, if you are looking for how to prepare your soil for planting flowers we have a great article you can check out right here.
If you’re unsure what kind of soil to use, a good basic bet is loam. Most popular garden plants prefer loam. That includes most peppers, tomatoes, and beans.
As we mentioned, it’s a combination of clay, silt, and sand, and offers the advantages of all three. Plants thrive in it because while the silt delivers the best water retention of the three kinds of soil, the sand helps keep it from compacting. That is important because plant roots spread where it is easiest, which requires that soil isn’t densely packed. Where soil is dense, plants are smaller and put out less fruit.
Most commercially available garden soil is loam, with about 10 percent of it decaying organic matter, which is called humus. You may also be lucky enough to have naturally occurring loam where you want to garden.
If you don’t, you can also amend the soil to synthesize loam. Look for commercially available amendments to either help break up clay or to provide more body to the soil.
If you buy either amendments or the soil itself, keep soil ph in mind. Plants do best with a ph of approximately 6.5.
First runner-up–Sandy loam
Most people look at a thriving tomato plant and think just about what is happening above the surface. One key to a successful garden is remembering that what happens below is just as important.
That is especially true for plants where the most important growth is taking place under the surface. Plants like carrots, parsnips, and potatoes do best where the soil makes it easier for them to bulk up. You get bigger, juicier spuds where they don’t have to expend a lot of energy pushing soil out of the way.
For those plants, a loam that is a little sandier is preferable. This allows them to benefit from the water retention and nutrients of silt in a sandier environment that aids in underground growth.
The downside is that you will need to pay closer attention to watering and nutrients. Less silt means less ability to retain both. You may need to water a little more frequently and may need to add more fertilizer. That means more work and more time paying attention to your plants.
You’ll need to keep a closer eye on the ph, too. The sandier the soil, the higher the ph-level it will have. Most sandy soils are between 7.0 and 8.0, which is higher than what most plants thrive in.
Of the three basic soil types, silt is closest to the consistency that provides the best growing results. It also does the best job of holding on to the decaying organic material that plays such a critical job of holding onto water and providing nutrients.
Silt is created by erosion by either wind or water and is the soil type most easily carried around by water or the wind. Sand granules are bigger and heavier, clay is so fine it clumps together.
When it comes to granule size, silt is in between sand’s large granules and the very fine granules in clay. That makes it easier for roots to spread out in it than clay, but not as easily as they do in sand.
That also means it is possible to compact silt to where roots have difficulty spreading out.
There is one vegetable that prefers sandy soil, and that vegetable is asparagus.
Asparagus is really just an oversized grass that spreads via underground runners. It spreads underground and when the weather just turns warm it sends shoots aboveground … which we harvest and grill with lemon and garlic.
As a plant, it has very modest needs. Vegetable plants that produce an abundance of fruit over a growing season need lots of water and lots of nutrients. Asparagus opens up into delicate bunches of fronds that spend all summer gathering energy for more underground growth until the next spring. You can grow it in soil that is practically a beach.
We bring this up to demonstrate that vegetable plants have a wide variety of needs when it comes to soil and water and that even soil you think is unsuitable for growing things is for the right plant.
The drawback to sandy soil is that it does a poor job of retaining moisture and nutrients because there is nothing to hold onto it. By the way, this also translates into less nutritious vegetables.
If your soil is sandy, you can always amend it by adding some silt and humus to help it with its water retention. Make sure to test it for its ph-level.
Or, you can just grow a field of asparagus.
Getting it right
Making sure you have the right soil type starts with knowing what plants you want to grow, because each kind thrives in different environments.
In general, plants that produce multiple sets of fruits will do better in a loam, while tubers or things that produce underground roots — like asparagus — do better with sandier soils. If you have a specific variety of plant, an heirloom tomato, then research what kind of soil it does best in. A tomato native to Italy will have different growing preferences than a tomato native to Germany.
We’d also suggest planning your garden so that plants that do best in the same kind of soil are grown near one another. If you growing asparagus, carrots, tomatoes, and peppers, for instance, build a bed for the carrots and asparagus and one for the peppers and tomatoes.
If your soil isn’t perfect for what you plan to grow, don’t despair. You can either amend what you have or just purchase pre-blended garden soil.
Amending it is as simple as mixing in other kinds of soil. While clay is generally the worst soil for growing vegetables, you can blend in sandy and silt to improve it as a growing medium. You can also remove the soil from where you want to grow plants and replace it with pre-blended garden soil. If you’re growing plants that prefer slightly sandier soil, you can add some extra sand.
Make sure the soil is comprised of about 10 percent humus. Humus is decaying organic material that adds nutrients to your soil, aids in water retention, and helps minimize soil compaction. Most pre-mixed garden soils already have it. You can make it at home by composting your vegetable leftovers that might otherwise go into the garbage. Because humus is decaying, every so often you’ll need to add some more to keep up on its benefits.
Another thing to look for is the ph level. This is important because if your soil’s ph is too high or low, that can not only inhibit plant growth and fruit development it can lock away nutrients from plants. In general, a ph of around 6.5 is ideal.
One thing to keep in mind is that soil isn’t a one-off thing. When you get your soil just right, you’ll need to keep it right. A successful garden means plants depleting the soil of nutrients, and it will eventually compact. Consider your soil to be an ongoing project.
We hope you found value in our little guide on the best soil for vegetables. We wish you the best and a bountiful harvest of delicious, nutritious food.