10 Vegetable Garden Mistakes Beginners Make (I’ve Made Every One)

There are a lot of glossy photos of amazing gardens out there, and sometimes they seem too good to be true. After a talk I gave, someone asked me what was really going on behind the beautiful photos. That’s a fair question, because every gardener makes vegetable garden mistakes, me included.

I still remember my first gardening season: celebrating my first ripe tomato, then crying over a row of beans that didn’t make it. Your first season can be exciting, overwhelming, triumphant and heartbreaking all at the same time. And honestly, after many years of gardening and working with hundreds of gardeners, I still have seasons like that.

Here are 10 of the most common vegetable garden mistakes, the ones I see most often in beginners and the ones I’ve made myself, plus what I do differently now.

#1: Starting With a Garden That’s Too Big

Of all the vegetable garden mistakes I see beginners make, the most common is starting with a garden that’s way too big.My first garden was in a community garden. The standard plot was 20′ x 20′. Over time, I noticed that for many gardeners, this size was often too big for them to keep up with, and a lot of those plots ended up neglected.

My own garden is about 1,600 square feet, which is big for a city lot, but I have 25 years of gardening experience under my belt. When you’re starting out, you need to be honest with yourself about how much time you truly have to devote to your garden.

What I recommend: start with two or three raised beds (a 4′ x 8′ bed is a common size). Fill them with the five vegetables you eat most that coincide with the easiest vegetables to grow, and expand once you’ve got the hang of it. Here’s how to start a small vegetable garden and make the most of it.

#2: Putting Your Garden in the Wrong Spot

You simply cannot have a garden without sun. It’s the most important factor in your garden’s success, followed closely by soil health. Vegetables do best in full sun, which is over 8 hours a day.

When I used to visit people’s yards to help them plan a garden, they’d often lead me to the spot they thought got the most sun. Often they were mistaken. It was a spot that got lots of sun in the evening when they were home, but was in the shade the rest of the day.

What I recommend: Give your sun-loving crops the sunniest spot you have. Here are the minimums to keep in mind.

• Fruiting vegetables: 8 hours of sun (tomatoes, peppers, eggplant, cucumbers, melons, squash)
• Root vegetables: 6 hours (carrots, beets, turnips, radishes, parsnips)
• Leafy vegetables: 4 hours (lettuce, spinach, collards, chard)

Sun-loving plants do much better with afternoon and evening sun, while root crops do fine with morning sun. If your garden is on the shady side, focus on greens and roots, and plant a little closer together than recommended, since the plants likely won’t reach full size. In all my years of visiting yards, I’ve only met one person who truly didn’t have enough sun for a garden. 

#3: Buying Plants Without Knowing the Variety

The variety you plant can make or break your harvest. But seedlings from a hardware store or big-box nursery often don’t even list a variety name, so you have no idea what you’re getting.

I learned this one myself with flowers. I bought verbena bonariensis from a nursery, and the plants weren’t true to type: they came up in the wrong color. I ended up pulling them out so they wouldn’t reseed all over the garden.

What I do now: I buy seedlings from farmers markets, ideally from CSA farmers. They grow these varieties themselves and know what works in your area. Or I start my own from seed so I know exactly what I’m planting.

#4: Not Keeping Seeds Watered Until They Sprout

Direct-seeded crops like carrots, beets and beans need steady moisture to germinate. Some seeds, like carrots, can take up to three weeks to come up, so it’s easy to plant them in the ground and forget about them. If the soil dries out during that time, the seeds won’t sprout.

What I do now: I water newly planted seeds lightly every day (twice if it’s hot and dry) until they sprout, then cut back to once or twice a week depending on rain. In the heat of summer, I water twice a day and cover the bed with lightweight row cover to hold in moisture. Here’s how I get fall seeds to germinate in hot weather.

#5: Watering Too Often, Too Lightly or From Overhead

Frequent, shallow watering causes your plants’ roots to stay at the surface of the soil, where they dry out fast. And overhead sprinklers lose a lot of water to evaporation. They also wet the leaves, which encourages fungal disease on squash, cucumbers and tomatoes.

It’s also easy to overestimate how much it rained. My rain gauge once read 1/10 of an inch after what sounded like a heavy storm!

What I do now: vegetable plants need about one inch of water per week, including rain. I water deeply and less often, in the morning if I can (never in the middle of a hot afternoon), and right at the base of each plant, holding my watering wand there until the water starts to pool. A rain gauge tells me whether I need to water at all. Here are my secrets to watering your vegetable garden the right way.

#6: Planting Too Close Together (or Too Far Apart)

There’s definitely a sweet spot with spacing between plants in the garden. If you plant things too close together, they end up competing for space, nutrients and water. Plants spaced too far apart leave bare soil for weeds and waste precious garden space.

This is one of the vegetable garden mistakes I’m most guilty of, especially with trellises. One year, in my enthusiasm, I completely overplanted two cattle panel trellises. A Love Vine took over one of them, and the other trellis was so overplanted it shaded out the crops around it.

What I do now: aim for plants whose leaves are just touching when they’re full size. My pepper plants in August are a good example. A full, dense canopy shades the soil, holds in moisture and keeps weeds down. See my guides to pepper plant spacing and building a cattle panel trellis.

#7: Letting Low Tunnels and Cold Frames Overheat

Cold frames and plastic-covered low tunnels can heat up fast on a sunny day, even when it’s cold outside. One spring afternoon, I checked my low tunnel and it was 109 degrees in there! My cool-weather crops got stressed and a lot of them bolted early.

What I do now: I vent my covers on sunny days and keep a thermometer inside so I know how hot it’s getting. And about four to six weeks before my last frost, I swap the plastic for row cover, which traps a little heat without cooking my plants. Here’s when to remove row cover in spring.

#8: Skipping Row Cover for Pests

One season, cabbage moths destroyed my entire lacinato kale crop. Interestingly, they left my curly kale alone.

What I do now: I use row cover as a physical barrier on crops that pests love. It keeps white cabbage butterflies from laying eggs on kale and other brassicas. See how I use row cover in spring for pest protection too.

#9: Expecting to Fix Your Soil in One Season

Sun and soil are the two most important factors in your garden’s success, and when gardeners have problems, one (or both!) is usually the cause.

One year my beans turned yellow just as they started producing. I tested my soil and added amendments more than once, and it still didn’t completely solve the problem. That’s when I realized that building fertile garden soil is a much longer-term project than I’d expected.

What I do now: start with a soil test through your local Cooperative Extension office. It will measure phosphorus, potassium, organic matter and pH, and tell you what to add. (If you live in an older house with lead paint or near an old gas station or factory, add a test for lead and heavy metals.) In my own garden, which started with poor soil, I’ve taken a multistep approach over the years: adding the nutrients my soil test recommended, chicken manure from my coop, compost from my home bin and a local supplier, and cover crops. If you’re filling raised beds, make sure your soil comes from a source you trust and doesn’t contain herbicides. See my guides to soil testing and compost for your vegetable garden.

#10: Not Writing Anything Down

Every fall I think I’ll remember my vegetable garden mistakes and what worked. I never do. Gardening isn’t an exact science, and the details are what help you do better next year.

What I do now: Throughout the course of every season, I jot down what went well, what didn’t and what I want to try next year. I keep it all in a garden binder. Here’s my gardening journal template to make it easy.

Frequently Asked Questions

What is the most common mistake first-time gardeners make? Starting with a garden that’s way too big. A big garden quickly becomes overwhelming to plant, weed and water. Start with a 10′ x 10′ plot or two or three raised beds, grow the vegetables you eat most, and expand once you’ve got the hang of it.

What are the easiest vegetables for beginners? Some of my favorite easy vegetables are spinach, beets, arugula, cilantro and radishes. They all grow from seed and handle cool weather well. Read my beginners guide to 15 easy vegetables to grow.

How do I avoid making the same mistakes next year? Write them down. At the end of every season, note what went well, what didn’t and what you want to try next time. A simple gardening journal makes it easy.

The Good News About Vegetable Garden Mistakes

Every gardening season is a fresh start. The mistakes you made this year are exactly what will make next year’s garden better, as long as you make note of them, absorb the lessons and try something different.