Short answer: no, but with some caveats. You can grow happy, lovely vegetables without adding compost to rich, healthy soil!
But rich, healthy soil in the ground is hard to come by these days. In order for plants to thrive, the soil needs nutrients and structure that likely aren’t naturally occurring in your backyard plot. As any experimenting home gardener knows, planting straight into the “unconditioned” ground will not yield a productive plant of any kind, vegetable or not.
Most backyard earth isn’t soil at all, it’s just dirt. Toasted, eroded, nutrient-less dirt, filled with traces of industrial chemicals.
It needs help.
It needs compost!
Picking up a bag of soil at your local gardening store? Chances are, some compost has already been added to that product, too—or some other compost-like additions.
So, do you really need compost to grow veggies successfully? Unless you live in the Fertile Crescent of ancient Mesopotamia, all signs point to yes.
Why compost to grow vegetables?
Healthier soil grows healthier plants. And compost makes the soil healthier. It improves soil structure, stabilizes pH, and adds important organisms to the soil. Compost can help your plants resist diseases and insects, grow more heartily, and produce more. Healthier soil=more veggies.
Compost isn’t just for vegetable-producing garden beds; use it on everything from flowers to herbs, and even houseplants. It can be used outdoors, indoors, in containers or raised beds, and right on the ground.
Pros of Compost – Nutrients
When you add compost to your soil, good microbes and soil life (including earthworms) get food, too. Trusty, benevolent microorganisms in soil have been breaking down organic matter into nutrients like nitrogen and potassium for eons. Nowadays, they just need some help from us to thrive.
These nutrients don’t just help your plants grow, they are also good for you! Remember that everything you put on your plants goes into your plants, and therefore into your body when you eat your homegrown fruits, herbs, and vegetables.
Pros of Compost – Soil structure and drainage
With its light and fluffy texture, compost helps with good drainage in clay-heavy soil and retains water in sandy soil. Compost improves soil by bulking up its organic matter and improving moisture and nutrient retention.
Pros of Compost – Building soil over time
Adding compost to your garden is a long-term investment. Compost worked into soil becomes a permanent asset, increasing microorganism diversity. The soil will continue to grow in health and stability as the years roll on, helping your little corner of the universe to prevent erosion and give back to the land that sustains us all.
This is great news for your perennial plants, too.
Pros of Compost – Sustainability
Stop putting your organic scraps into landfills! If you understate your own home composting system, turning kitchen scraps, yard waste, and more into rich soil amendment is a staple of reducing household waste. You also won’t need plastic bags full of compost from the gardening store anymore.
Did you know there are also composting toilets? In short, they breakdown your fecal matter and urine using decomposition and evaporation, so that you end up with soil-like compost. If you want to learn more about how this process works, then click here.
Compost: The Ultimate Renewable Resource
Think of a home composting system as your own personal organic recycling center. You are turning waste into vegetables! Well, with a few steps in between.
If you don’t yet have a home composting system, check out our in-depth guide to the 10 Best Composting Methods or The Vermicomposting Guide to find a technique that works for you.
How to add compost to your soil
Compost is a soil amendment, not a replacement. This dark, crumbly, nutrient-rich “aged” organic waste serves as a soil conditioner. That means it’s not a soil replacement.
Planting in pure compost is a big no-no.
Unlike soil, compost does not contain sand, silt, or clay, so it won’t provide the stability necessary for strong root systems. Planting in pure compost will cause problems with water retention and stability. It won’t last long, poor thing.
Adding Compost to Your Garden – Basic soil preparation
It’s best to Incorporate most compost into your garden in the spring. As you turn and prepare your planting area, add 3 or 4 inches of compost and turn it into the soil about 8 inches deep. It’s important to mix the compost into your soil very thoroughly.
Compost will “feed” your soil for a long time, but should be replenished every year. Over the years, you may be able to lessen how much compost you add.
You’ll be able to tell by the quality of your soil. After years of good gardening practices, tilling, and composting, you should notice your base soil becomes darker, fluffier, more “organic smelling” and more full of happy earthworms.
Using compost on your plants
Different crops benefit (or be worse-off) with different amounts and applications, but most every plant will benefit from compost. Vegetable gardens are especially good places for compost because, as I mentioned before, healthy soil yields a better harvest.
Container gardening with compost
It’s a wonderful idea to add compost to your container plants. One mistake a lot of people make is simple sprinkling compost on top of their potted plants like a dusting of Parmigiano Reggiano cheese on some pasta. That won’t necessarily hurt the plants, but it simply is not the best use of your valuable compost.
Just like when you use compost in your raised beds or in-ground soil, be sure to thoroughly mix your compost in with your soil to at least 6-8 inches of depth.
Planting trees with compost
Just because trees are bigger than vegetable plants doesn’t mean they don’t need a little support from the compost! Using compost on trees and shrubs, whether they are fruit- or berry-bearing or not, is extremely beneficial.
Spread just about half of an inch of compost on the bare soil under the tree, but not right up against the trunk. Cover with a small layer of organic mulch (not compost mulch) or dry leaves.
Mulching with compost
Compost can also be used as mulch—a covering to protect topsoil. Compost mulch is a great way to keep pests out of root systems, repress weeds, and maintain soil moisture and temperature. A nice 3-inch layer of rich compost can serve as mulch around in-ground vegetable plants, flower beds, or around trees.
Now you’re confused, because I just told you to sprinkle compost on top of your soil like parmesan cheese, right? I stand by that rule. Mulching is intended to cover soil, not to amend it, so that’s why mixing it in is not necessary. You want to form a protective layer above the true soil.
Mulching also shouldn’t be done directly on any plant; avoid mulching too close to the main stem or trunk of your plant.
Can I just use fertilizer instead of compost?
Short answer: go ahead, if you don’t care about all the pro-compost points I’ve already covered.
Fertilizer is the “quick fix” to compost’s long-term solution. Think of compost like eating a lifelong healthy diet, whereas using fertilizing is like taking a bunch of vitamins when you feel like you’re catching a cold. Compost bolsters the soil long-term, whereas fertilizer just gives that plant a vitamin boost.
That’s not to say that fertilizer isn’t useful. Using organic fertilizers short-term is a great way to give your garden a jump-start or help weak plants get healthier if you’ve already done composting.
Fertilizers focus on adding the “big 3” nutrients to plants: nitrogen, phosphorus, and potassium. Compost adds lots of other minor but essential nutrients.
It’s also very important to note that a vast number of fertilizers on the market are not organic. Instead, they’re made with harmful (to you, the planet, and wildlife) chemicals that should never be near living creatures in the first place. Dr. Earth producers perhaps the most trusted organic fertilizers for all sorts of plants, including veggies.