Don’t feed plants? What? Don’t plants need nutrients to grow? Sure they do. Well, doesn’t that mean that you should feed the plants? No, it doesn’t. This is one of the really big myths in gardening. Almost everybody thinks they need to feed their plants. How many times have you seen someone on the internet asking the question, “What should I feed this particular plant with? What type of fertilizer should I use to feed my plants? Well. I have news for you. We don’t feed plants when we fertilize. We replace the nutrients that are missing in the soil.
We do not feed plants. Now that might sound like simple semantics, but it’s not. It’s a critical piece of information that gardeners have to know. Once you know that you’ll do a much better job growing plants and you’re going to save yourself a ton of money.

Now when I’m talking about fertilizer, I’m including both synthetic fertilizer and organic fertilizer, so things like compost or manure doesn’t really matter. We don’t use any of those things to feed plants. I’ll explain why that’s true. And then I’ll go and look at some specific situations in the garden, like growing things in the ground, vegetable gardens and ornamental gardens. How are they different? What about raised beds? And then we’ll look at containers and house plants? Does this apply to all those situations?

The reason we fertilize is to add the nutrients that are missing in soil. We do not feed plants. Plants will take the nutrients they need from the soil. A gardener’s job is to make sure that soil has enough nutrients so the plants can take the nutrients they want from that soil. Now many gardeners will use a rose fertilizer for their roses because they think they’re feeding roses, but they’re really doing it incorrectly. They need to replace the nutrients that are missing and this message isn’t about roses. It’s about everything that we grow trees, shrubs, perennials, annuals doesn’t matter in every case. We simply have to make sure the soil has nutrients that plants need. Once you understand this, you’ll approach fertilizing in a completely different way.

People publish these rules and these memes that tell you to look at the symptoms of the leaves and that tells you the missing nutrients will have news for you. You simply can’t tell a nutrient deficiency by looking at the leaves. The only way to know what’s missing in your soil is to get a soil test. There are home test kits that you can buy at nurseries and garden centers, but those kits are pretty much useless. If you really want to know what’s missing in your soil, you should get it done at a proper lab.

So what should you use well if you’ve had a soil test done? Then do what the soil test says. If you’re low in potassium, you add potassium. If you need magnesium, you add magnesium. Follow the recommendations of the soil test that will tell you what your soil needs. Now I’m not recommending you go get a soil test unless you have a specific problem in the garden. And I know most gardeners aren’t going to bother with a soil test and I don’t blame you. So what do you do? Well, you don’t know what’s missing. So what I recommend you do is grow stuff. If that stuff grows, you don’t have a deficiency. Now, if your plants aren’t growing well, then have your soil tested. You could have a deficiency or you have too much of something and that can cause plants not to grow as well. Grow stuff. If it grows well, forget the soil test and don’t fertilize. If you have a problem, get your soil tested and do what it says.

So let’s assume you haven’t done a soil test and let’s look at some specific cases. What should you do? The first one i’d like to look at is a standard garden bed. It’s an ornamental bed. You have some trees and shrubs, some perennials, some annuals. What should you use for fertilizer there? Well, since you don’t have a deficiency, you don’t know what to add. Don’t add anything. What I recommend you do is put on a couple inches of compost or manure that adds a low amount of nutrients. It will help fill in anything that might be missing. Adds a bit of nitrogen. Nitrogen is almost always on the low side in a garden and that’s it. Don’t fertilize. I grow 3 thousand different things, i never fertilize any of them. I put on some wood chips as mulch, and I take organic matter from the garden and leave it in the garden that adds a small amount of nutrients. And that’s it. I don’t need fertilizer.

What about a vegetable garden? Well, the same rules apply for the vegetable garden. Except there we generally want plants to grow quicker and so it’s a good idea to put on a little nitrogen. Again nitrogen is one nutrient that is almost always on the low side and that’s it. Compost manure, little nitrogen.

What about raised beds? Well, that depends very much on how you built the bed. If you used real soil in them, treat them like a garden, that soil already has nutrients in it, and you almost certainly put on some compost and manure when you made that raised bad, so treat it like any other garden. Now if you made your raised beds with a lot of organic matter, so you sort of fill them with compost, then you shouldn’t put anything on that. That compost is probably too rich and in particular those kinds of raised beds have a problem with high toxic levels of phosphate. So grow things. And if they’re growing well, don’t do anything.
If they’re not growing well, get a soil test done and I’ll bet you, you have high phosphate.

Containers? What do we do there? Well. Containers are very similar to house plants. I mean house plants grow on containers as well, and in both cases we generally use a soulless mix PE moss core, something like that. Those products don’t have natural nutrients. The plants only have access to the nutrients we put into those container. The other issue with containers is that we tend to water a lot because they dry out so fast and we water extra to let the water run out the bottom and that washes nutrients away. So we can assume that in containers that have a soil less mix, we have to supply the nutrients for the plant and what you want to add. There is a synthetic fertilizer with a ratio of three and two that’s suitable for virtually every kind of plant and you want to make sure the micronutrients are in there. So a good soluble synthetic fertilizer with the micronutrients. Now if you want to go organic, you can do that too. But just be aware that organ organic products take a long time to break down and it’s very likely that you’re under fertilizing with organic product. Synthetic works so much better and both synthetic and organic produce the same nutrients. By the time the plant absorbs that nutrient it can’t tell the difference where it came from, so I prefer synthetic for containers. Now, if you want to learn more about soil and nutrients. I have two great sources for you. I’ve written a book called Soil Signs for Gardeners.
It’s choked full of all kinds of useful information.

About The Author

Robert Pavlis is a well-known speaker, and educator with over 40 years of gardening experience. He is the author of Building Natural Ponds, and publishes the popular gardening blogs; GardenMyths.com and GardenFundamentals.com. As the owner and head gardener of Aspen Grove Gardens, a six-acre botanical garden, he grows 3,000 varieties of plants.