171-Gardening Mistakes to Avoid

| Care, Podcast

I like to encourage risk-taking in the garden because the stakes are usually very low, and we know that “mistake” is another word for “learning opportunity.” However, there are some common gardening mistakes to avoid that you don’t need to learn about the hard way.

In this week’s episode, I identify 10 of the most common gardening mistakes and share tried and true practices to prevent them from ever happening. These mistakes not only cause problems for gardeners, but there are also environmental concerns as well that you may not have thought about before.


Gardening Mistake #1: Not Planning Ahead

Planting and tending a garden poses an interesting dichotomy: Gardeners clearly exhibit an appreciation for deferred reward — otherwise, we wouldn’t be gardeners — but we also engage in behaviors that provide an outlet for instant gratification. The latter is how gardeners find themselves in trouble.

For many of us, it starts at the nursery, where we make emotional purchases of plants and seeds that we have nowhere to grow. We succumb to the allure of large displays of plants in bloom, or the lustrous foliage of woody ornamental shrubs perfectly arranged so that we can’t help but notice them. 

My justification came from having a large lot in need of plenty of landscaping. It helped that I have a working knowledge of plants so that I could site them appropriately at home, but even that knowledge couldn’t stop me from buying some plants I had no real use for.

It isn’t until we get home with our purchases that it dawns on us that we have no idea where to place our new acquisitions — and no time to plant them even if we knew where they should go.  

Many of my ill-advised impulse purchases, especially annuals, went from the nursery, to my driveway “staging area,” to the compost bin, never having the chance to spread their roots beyond the plastic walls of the nursery pots or flats they arrived in. But at least my driveway looked great! It was a sight to see. In fact, when I lived in a subdivision that presented a “Yard of the Month” award — which I never won — a new award was created, just for me. It was the “Driveway of the Year,” and I was the first and only recipient.

Thinking of all the money I have spent on plants that were never planted, I have a new appreciation for why compost is called “black gold.”


Seedlings in a plant nursery

It’s easy to leave the plant nursery with more plants than you have space for. Planning ahead to make sure you have a place for all your new purchases — and the time to plant them — is key.


Gardening Mistake #2: Improper Spacing

An even greater expense arises from planting in the wrong place or spacing plants improperly. Plants, like puppies, are really cute when they’re small — but it’s very important to know how big they’ll be when full-grown.

If you didn’t plan ahead for your plant to reach its full potential, you will have to work much harder later on. Plants that looked just fine when they were newly planted can, years later, crack driveways and sidewalks. The branches of a tree or shrub planted too close to a house must be cut back regularly to stop them from overtaking the house. 

We like that instant mature-looking landscape that comes with foundation and streetside plantings, and it’s easy to do with small plants and a few trees planted close together. But packing plants together closely with no consideration for how they will look two, five, or even 10 years later always leads to problems. The plants will eventually compete with each other for available sunlight and air circulation — and both are critical to plant health.

Some gardeners will see their overcrowded plants ailing and will think the cure is fertilizing and applying pesticides, but these will not resolve problems caused by overcrowding. 

To alleviate overcrowding, plants should be thinned out or transplanted elsewhere. Thinning out means removing and tossing plants that you have dedicated time and expense to — and that’s a drag. Transplanting, meanwhile, is laborious, and the plant won’t always survive the process. 

Many issues can be avoided by reading the information tag that came on a plant from the nursery. The tag not only enlightens us on a plant’s size at maturity but also its preference for sun versus shade and its preferred soil conditions. It comes down to a maxim that is my favorite and the most important in landscaping: “right plant, right place.”

“Right plant, right place” is the bottom-line to avoiding many gardening mistakes that are caused by the pursuit of instant gardening gratification. A properly sited plant or tree rarely needs pruning to control size. It also thrives when provided with ideal conditions, and rarely needs supplemental attention to be the best plant it can be.

Conversely, plants sited in the wrong place will never look their best. Simply trying to survive can exhaust their energy reserves, and as a result, they become stressed, which makes them vulnerable to pests and diseases. They may also look like they need fertilizer when what they really need is space or light. 

Gardeners who do not have an organic mindset are often too quick to react to plant distress signals with chemical cocktails when all that is needed is to move a plant to a more suitable location. A plant in the right location will be both healthier and naturally more resistant to disease and pests. 

Exercising patience and giving plants the time and room they need to mature gracefully will delay gratification but will also reward us with the healthiest, best looking, and lowest maintenance landscape. Get in the habit of reading the plant tag, and even better, do your homework on a plant and on your available space before you purchase anything that you may later regret buying.

Gardening Mistake #3: Improper Use of Chemicals

To be clear, I am an organic gardener, through and through. So when I refer to improperly using chemicals, I am not just talking about synthetics. I’m talking about both non-organic and organic insecticides, herbicides, fungicides, and fertilizers.

Even organic products have damaging effects when used improperly. Runoff, overspray, and overuse can result in widespread consequences beyond your intended target.

For example, in my recent podcast episode on gardening pet peeves, I spoke about mosquito spray companies that purport to be all-natural and eco-friendly because they are using natural products. Those products may be natural, but they are not specific to mosquitos, so the killing impact is much broader than the spray companies let on.

The problem with using broad-spectrum insecticides, even when they are natural and organic, is that they kill the beneficial insects that are necessary to a healthy ecosystem while they are killing mosquitoes, ticks and garden pests.

Neem oil and insecticidal soap are two more examples of organic products that are nonselective insect controls. That means they may harm or kill whatever insects they come in contact with, good or bad.

Vinegar (acetic acid) is a natural product that is often recommended as an herbicide alternative to the most common non-organic option, Roundup (glyphosate), but even vinegar becomes a problem when overapplied or when the concentration is too strong. Vinegar runoff can be harmful to lizards and frogs as well as other amphibious creatures. It’s a danger to the person applying it too — remember, it is an acid and can blind you when highly concentrated. 

In short: All chemicals, both organic and synthetic, must be applied with discretion. Read the label before using the product, make sure it is the right product for the job, and don’t use more than you need.


Frog on fence

Vinegar (acetic acid) is an example of a natural product that is often recommended as an herbicide alternative to Roundup (glyphosate). But you have to be careful since vinegar can be harmful to the amphibians that live in the garden.


Gardening Mistake #4: Failing to Identify the Problem

As I said, don’t assume because your plant is struggling that it needs fertilizer or a pesticide. The problem could be something as simple as a bad location or underwatering. This is why it’s a good idea to get a soil test before applying fertilizer. A reliable soil test will let you know what nutrients the soil is lacking as well as what nutrients it has in abundance. You don’t want to be applying more of what your soil already has more than enough of — that won’t help your plants thrive.

At what point did we decide that every problem in the landscape and garden could be solved with a chemical? In our busy lives, it just seems like the more expedient thing to do. Unfortunately, all too often, there’s not much consideration given to the potential consequences of these conveniences.  

If you’re going to be a good steward of your garden and the environment under your watch, it’s your duty to identify the true problem before deciding how to intervene. This is a necessary step before finding the most effective, most targeted solution. 

In many cases, you can get a plant disease or pest problem under control without the use of chemicals. And if you do find it necessary to use pesticides, look for selective controls first. Selective controls target a specific type of organism while leaving others unharmed. Broad-spectrum controls, on the other hand, can’t tell damaging Japanese beetles and beneficial lady beetles apart. Indiscriminate spraying of both organic and synthetic products is lethal to both as well. 


Hedge with browning leaves

Just because a plant is struggling doesn’t mean it needs fertilizer or another chemical to help it bounce back. Identify the problem first before deciding how to intervene.


Gardening Mistake #5: Improper Timing When Applying Pesticides

Two separate issues relate to proper timing when using pesticides: The stage in the insect’s life cycle, and the time of day when applications are made.

Insecticide applications should be timed to when the insect is most vulnerable. Properly timed applications will be the most effective and will stand the greatest chance of breaking an insect’s cycle of infestation. This also minimizes the impact on other insects and the environment. 

Many nonselective pesticides are engineered to kill offending insects at any stage of their life cycle. Due to their persistence in the environment, their widespread reach comes with a price to beneficial and neutral insects that have important roles to play.

Insecticidal soap is an example of an organic product that must be timed properly to have the desired effect. To control bean beetles, for instance, insecticidal soap is effective during the second and third stages of their four-stage life cycle. When they hatch as larvae and when they progress to stage three as pupas, their bodies are soft, and a desiccating control such as insecticidal soap is effective on soft-bodied insects. But the same control won’t have any effect on an adult bean beetle, which has hard wing covers similar to a lady beetle. Insecticidal soap, which works by drying out soft-bodied insects, will have no effect.

Concerning time of day, if you are going to apply nonselective chemicals, wait until as late in the day as possible — after the beneficial insects have retired for the evening. The next morning, when pollinators return to the garden, their exposure risk through direct contact with the insecticides will be reduced. The worst mistake you can make with nonselective controls is to spray between the morning and afternoon, when the garden is buzzing with insects.


Bean beetles

When applying pesticides, timing is everything. For example, insecticidal soap is effective during the second and third stage of a bean beetle’s life cycle when their bodies are soft. But the same control won’t affect an adult bean beetle.


Gardening Mistake #6: Failing to Keep on Target

Applying chemicals broadly can have unintended consequences. Many of the most common garden insecticides have killing power that goes far beyond the pests they were applied to control.

It helps to understand that insect pests rarely stray from their preferred diets. Hornworms on your tomatoes and peppers won’t take over your entire garden — so why apply hornworm control anywhere else but your tomatoes and peppers? 

The same principle applies to herbicides and fertilizers. The label on most consumer weed-killing products will warn that they are toxic to aquatic invertebrates and nontarget plants. Fertilizers — the primary ingredients of which in most cases are nitrogen and phosphorus — are similarly of concern for waterways. Nitrogen runoff promotes the growth of organisms that deplete dissolved oxygen levels in water bodies, and that harms aquatic life, including fish. Phosphorus supports aggressive growth of algae, leading to a significant reduction in water quality and an adverse impact on marine life.

Gardening Mistake #7: Failing to Follow the Directions

Don’t underestimate the potency of synthetic chemical products. People often assume that if some is good, more is better, but that’s just not the case. Packaging information on application rates is very specific in order to provide maximum efficiency while providing a reasonable level of safety to people, pets, and the environment. 

Know your foe, understand the options for control, and take the time to learn how to exercise those controls properly. The more precise you are in your approach to pest management and fertilizing, the less negative impact your actions will have.

Gardening Mistake #8: Lack of Soil Preparation

In addition to siting a plant in the right place, second in my book is having great soil. More plants live, die, struggle, or thrive based on the condition of the earth they are planted into. 

If I had 10 hours to devote to planting a garden, I’d spend nine of them preparing the soil. The lack of sufficient soil preparation at the time of planting is one of the primary reasons for an unhealthy landscape and one of the most avoidable mistakes we make.

I’d like to share shortcuts to achieving great results in your garden, but when it comes to soil preparation, there are none. Instant-gratification landscapes consider what we can see, while failing to give the soil below the attention it deserves. But the soil is a plant or tree’s home for the rest of its life, and these living organisms need to be in the proper environment to thrive.

The two main issues that soil preparation addresses are the supply of natural nutrients and the soil structure.

Nutrients found in soil become depleted over time as plants take them up or as they leach deeper into the earth. Microorganisms that are critical to a healthy soil food web provide an environment where nutrients become available to plants in a soluble form. When gardeners talk about “building our soil,” it’s not a one-and-done process. Just like how you need to pay attention to what you put into your body every day to achieve optimal health, paying attention to what goes into your soil on a consistent basis will provide optimal plant health. 

Soil structure pertains to how well your soil retains water. Your native soil is likely either too heavy and slow to drain, or too sandy and quick to drain. Heavy soil can drown your plants, while sandy soil can leave them to dry out and die.

Fortunately, whatever the starting condition of your native soil, the solution is the same: add sufficient organic matter. Examples include compost, aged manure, and decomposed leaves. Each of these works to improve the structure of existing soil.

Soil with good structure drains well while retaining sufficient moisture. The goal in creating the ideal mix is to add enough organic matter so the soil binds together when squeezed, yet breaks apart easily when disturbed.

Well-prepared soil not only passes the squeeze test, it also contains plenty of nutrients and microorganisms to provide an optimal environment to promote the establishment, health and growth of whatever is planted there. 

Compost is great for this because it is an all-inclusive soil amendment, providing nutrients and promoting a vibrant soil ecosystem. Whatever amendment you are using, lightly work it into the top inch or two of the soil, or simply topdress your garden beds or lawn. You don’t have to work it in because the soil food web will bring it down further.


Joe Lamp'l amending soil

Nutrients in the soil become depleted over time. It’s important to add back those nutrients by amending with organic matter like compost.


Gardening Mistake #9: Keeping Soil Surfaces Exposed

Another way to describe this gardening mistake is “failing to use mulch.” Whether it be arborist’s woodchips, shredded leaves, straw,  or grass clippings, the mulch on top of your soil will prevent erosion, runoff, and compaction. 

Soil left exposed to the baking sun becomes a dried out hard surface that water can’t penetrate. Water droplets add to compaction by hammering the soil when there is no buffer — no mulch — to lessen the impact. Water always wants to go somewhere and to seek the lowest point, so what you end up with is runoff that will carry fertilizer, pesticides, and topsoil away with it. 

Exposed soil surfaces are also the No. 1 reason for excessive weeds in lawns and gardens. But with mulch, the weed seeds are denied the sunlight that many need to germinate. 

Another problem that arises is poor soil quality. When you fail to add a layer of organic mulch that will add nutrients to the soil as it breaks down, you are not replenishing the soil as fast as plants are taking up the nutrients. You can use compost as mulch too, though I like to consider compost as another layer of soil, and I add a layer of mulch after topdressing with compost.


Leaf mulch

One of the best ways to avoid leaving garden soil exposed is to apply a layer of shredded leaves as mulch. Mulch helps suppress weeds, retain moisture, and prevent soil from becoming compacted.


Gardening Mistake #10: Improper Watering

Improper watering is one of the most common problems seen in gardens and landscapes everywhere. Though improper watering may seem minor, the implications are broad. More plants, trees, and even lawns are killed or become diseased due to overwatering rather than underwatering. Not only that, the EPA estimates that we waste about half of all the water used outdoors.

Applying more water than plants and lawns need and can absorb leads to that chemical-polluted runoff I mentioned above. And unless your soil has excellent drainage, your soil will become waterlogged and your plants will die of drowning or root rot.

In addition to the issues created below the soil surface, overwatering leads to plant foliage staying damp for prolonged periods. These conditions are ripe for plant diseases to take hold, like summer brown patch in lawns. Shrubs and the plants in your vegetable garden are also adversely affected by excessive moisture. It’s best to water only once or twice a week rather than on a daily schedule.

Deep, infrequent watering encourages plant roots to grow further down into the soil to find moisture. Deeper roots give staying power in drought conditions and greater access to nutrients. Plants with shallow root structures will dry out quickly if water becomes scarce or your automatic irrigation system fails you.

Established plants and lawns thrive on just 1 inch of water a week — and that’s including rainfall. Subtract the amount of rainfall in a week from any supplemental watering. 

Another form of improper watering, off-target watering, is not only wasteful, it encourages weeds to grow. Overhead irrigation is a huge contributor to this, as wayward spray patterns water weeds and lead to runoff. The best alternative is to use soaker hoses or drip irrigation lines along the soil surface that will deliver water directly to the root zone, right where plants need it. Because of the slow water delivery rate of soaker hoses and drip systems, the plants have adequate time to take the water up before it washes away, taking soil nutrients and chemical pesticides with it. These systems have the added benefit of keeping foliage dry, thereby discouraging plant diseases.

Overhead watering is still the only practical way to irrigate a lawn, but you can adjust spray heads to keep them on target and keep the water off the street and driveway. You’ll be a better conservationist, and harmful runoff carrying dangerous chemicals into watersheds and aquifers will be reduced.


Drip irrigation

A great alternative to overhead watering is using drip irrigation along the soil surface to deliver water directly to the root zone.


If you haven’t listened to the podcast on gardening mistakes yet, you can scroll up the page and click the Play icon on the green bar found near the top of this page. 

What have you learned from your gardening mistakes? Share your lessons in the comments below.

Links & Resources

Episode 025: Five of the Biggest Mistakes in Tree Care

Episode 029: My Five Biggest Gardening Mistakes of All Time (and What I Learned From Them)

Episode 063: Garden Fertilizer Basics: What to Know Before You Grow

Episode 112: Efficient Watering in the Garden and Landscape and Why It Matters 

Episode 156:Why Mulch Matters in Every Garden: What You Need to Know

Episode 160: Gardening Pet Peeves – My Top 10 from Joe Lamp’l

joegardenerTV YouTube: Best Watering Tips for Trees & Shrubs

joegardenerTV YouTube: 5 Biggest Garden Mistakes & How to Avoid Them

joegardener Online Gardening Academy™: Three popular courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting!

joegardener Online Gardening Academy Essential Gardening Fundamentals: The basics on healthy soil, planting, watering techniques, composting, raised bed and other gardening methods, fertilizer, the many benefits of mulch, and more.

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joegardener Facebook

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*Disclosure: Some product links in this guide are affiliate links, which means we would get a commission if you purchase. However, none of the prices of these resources have been increased to compensate us. None of the items included in this list have any bearing on any compensation being an influencing factor on their inclusion here. The selection of all items featured in this post and podcast were based solely on merit and in no way influenced by any affiliate or financial incentive, or contractual relationship. At the time of this writing, Joe Lamp’l has professional relationships with the following companies who may have products included in this post and podcast: Rain Bird, Corona Tools, Milorganite, Soil3, Park Seed, and Exmark. These companies are either Brand Partners of and/or advertise on our website. However, we receive no additional compensation from the sales or promotion of their product through this guide. The inclusion of any products mentioned within this post is entirely independent and exclusive of any relationship. 

About Joe Lamp'l

Joe Lamp’l is the creator and “joe” behind joe gardener®. His lifetime passion and devotion to all things horticulture has led him to a long-time career as one of the country’s most recognized and trusted personalities in organic gardening and sustainability. That is most evident in his role as host and creator of Emmy Award-winning Growing a Greener World®, a national green-living lifestyle series on PBS currently broadcasting in its tenth season. When he’s not working in his large, raised bed vegetable garden, he’s likely planting or digging something up, or spending time with his family on their organic farm just north of Atlanta, GA.

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