Category: Garden Planning

Companion planting means growing certain plants near each other because they seem to help one another, whether by attracting pollinators, discouraging pests, providing shade or support or using space efficiently. It is one of the most popular ideas in home gardening.

Some companion pairings are well supported by research and practical experience, while others are based mostly on tradition. This guide explains the reasons companion planting can work, highlights common pairings and helps you plan a layout, while being honest about what is proven and what is folklore.

How Companion Planting Can Help

Attracting Beneficial Insects

Flowering plants can attract pollinators and predatory insects such as ladybugs, lacewings, hoverflies and parasitic wasps, which help control pests. Including flowers and herbs in vegetable gardens is one of the best-supported companion planting practices.

Trap Cropping

Some plants attract pests away from your main crops. For example, nasturtiums are often used as a trap crop for aphids. You then manage pests on the trap plants.

Physical Support and Shade

Tall plants can provide support or shade for others. Corn supports climbing beans in the traditional Three Sisters planting. Tall crops can shade lettuce in summer heat.

Efficient Use of Space

Pairing fast-growing crops with slow-growing ones, called interplanting, makes the most of space. Radishes sown between slower carrots are a classic example.

Soil Benefits

Legumes like beans and peas host bacteria that fix nitrogen in root nodules. Much of that nitrogen benefits later crops after the legumes are turned into the soil or decompose.

Confusing Pests

Mixed plantings may make it harder for some pests to find their host plants compared with large single-crop plantings.

Common Companion Pairings

Crop	Common companions	Reason often given
Tomatoes	Basil, marigolds, carrots, onions	Pollinators, space use, tradition
Peppers	Basil, onions, carrots	Space use, tradition
Cucumbers	Dill, nasturtiums, radishes, beans	Beneficial insects, trap crop
Squash	Nasturtiums, borage, corn, beans	Pollinators, Three Sisters
Beans	Corn, squash, carrots, cucumbers	Support, nitrogen, space
Carrots	Onions, leeks, radishes, lettuce	Space use; onions may deter carrot fly
Lettuce	Radishes, carrots, tall crops for shade	Space, shade
Brassicas	Dill, onions, nasturtiums, herbs	Beneficial insects, trap crops

Many of these combinations have strong traditional support, but scientific evidence for specific pest-repelling effects varies.

The Three Sisters

The Three Sisters is a traditional Indigenous planting system of corn, beans and squash:

• Corn provides a tall stalk for beans to climb.
• Beans add nitrogen to the soil over time.
• Squash spreads across the ground, shading out weeds and helping retain soil moisture.

The system works best with enough space and with varieties suited to growing together, such as pole beans that will not overwhelm the corn. Plant corn first and add beans once corn has a head start.

Helpful Flowers and Herbs

Marigolds

Often planted around vegetable gardens. Certain marigold types have been studied for effects on some root-knot nematodes, usually when grown as a dense cover crop rather than a few border plants. They also add color and attract some beneficial insects.

Nasturtiums

Commonly used as a trap crop for aphids and attract pollinators. Leaves and flowers are edible.

Borage

Attracts bees and other pollinators.

Dill, Fennel, Cilantro and Parsley

Flowers of the carrot family attract beneficial insects such as hoverflies and parasitic wasps. Note that fennel is often kept apart from many vegetables because of traditional claims that it inhibits growth.

Alyssum

Small flowers attract hoverflies, whose larvae eat aphids.

Zinnias, Cosmos and Sunflowers

Attract pollinators and add beauty.

See our guide to growing herbs in containers if you want herbs close to the kitchen.

Plants Often Kept Apart

Traditional guidance suggests separating some combinations:

• Beans and onions or garlic: Often said to stunt bean growth.
• Tomatoes and potatoes: Both are susceptible to some of the same diseases, such as late blight.
• Tomatoes and corn: Both can be affected by a common pest called the corn earworm (also known as tomato fruitworm).
• Brassicas and strawberries: Traditional advice, with limited evidence.
• Fennel and most vegetables: Traditional advice.

Some of these warnings have practical reasons, like shared diseases, while others are mostly tradition. Crop rotation and good spacing matter more than any single pairing.

How to Plan a Companion Layout

Step 1: List What You Want to Grow

Start with the vegetables you enjoy most.

Step 2: Group by Needs

Plants with similar sun, water and soil needs grow best together.

Step 3: Place Tall Plants Thoughtfully

In the Northern Hemisphere, tall plants usually go on the north side to avoid shading shorter crops, unless you want shade for heat-sensitive greens.

Step 4: Add Flowers and Herbs

Tuck flowers and herbs along edges, at bed corners and between crops to attract beneficial insects.

Step 5: Interplant Quick Crops

Sow radishes, lettuce or green onions in gaps around slower crops.

Step 6: Plan Rotation

Avoid planting the same crop family in the same spot year after year when possible. Keep simple records of what you planted where.

See our raised bed plans for a sample layout.

A Sample Companion Bed

For a 4-by-8-foot bed:

• North side: Tomatoes in cages with basil between them
• Middle: Peppers and bush beans
• South side: Lettuce, radishes and carrots
• Corners: Marigolds, nasturtiums and alyssum

Keeping Records to See What Works

Because companion planting results vary with climate, soil and local pests, your own observations are valuable. Each season, note:

• Which pairings you tried and where
• When pests appeared and which plants they favored
• Which flowers attracted the most bees and other visitors
• How harvests compared with previous years

A simple notebook or spreadsheet is enough. After two or three seasons, you will know which combinations are worth repeating in your garden and which you can skip. Combine your notes with guidance from your local cooperative extension service, which often has region-specific advice on pests and beneficial insects.

A Note on Scale

Many studies of companion effects are done at farm scale with large plantings. A single marigold beside a single tomato may not produce the same effect. Planting flowers in generous clumps or borders is more likely to attract beneficial insects in noticeable numbers.

Frequently Asked Questions

Does companion planting really work?

Some practices, such as attracting beneficial insects with flowers, using trap crops and interplanting for space, have good support. Claims that specific plants repel specific pests are mixed. Treat companion planting as one helpful tool among many.

Does basil improve tomato flavor?

This is a popular belief, but there is little solid evidence. Basil and tomatoes grow well together and are delicious together, which is reason enough.

Can companion planting replace pest control?

It can reduce some pest problems, but it works best combined with healthy soil, proper spacing, crop rotation and monitoring.

What are the easiest companion plants for beginners?

Marigolds, nasturtiums, basil, dill and alyssum are easy to grow and fit well in most vegetable gardens.

Should I worry about bad companions?

Focus mainly on practical issues like shared diseases and shading. Do not let traditional lists stop you from growing what you enjoy.

The Bottom Line

Companion planting is a useful, low-cost way to support a healthy garden. Add flowers and herbs to attract beneficial insects, use trap crops, interplant quick crops, consider the Three Sisters and keep crops with shared diseases apart. Combine these practices with good soil, spacing and rotation for the best results.

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Editorial note: Backyard Bloomer is independent and reader-supported. This guide is based on research into manufacturer documentation, published specifications and widely accepted best practices; we have not been paid to mention any product. If we add affiliate links in the future, they will be clearly disclosed per our Affiliate Disclosure.

Raised beds are one of the easiest ways to start a vegetable garden. They warm up faster in spring, drain well, keep paths separate from growing areas and let you build good soil from day one, even if your native ground is rocky, compacted or heavy clay. They also make gardening easier on your back and knees.

This guide walks through every decision a beginner needs to make: where to put the bed, how big to make it, what to build it from, how to fill it and what to plant in the first season.

Step 1: Choose the Right Spot

Location matters more than any other decision.

Sunlight

Most vegetables, especially fruiting crops like tomatoes, peppers, squash and cucumbers, need at least six to eight hours of direct sun a day. Leafy greens and many herbs can manage with somewhat less. Watch your yard for a full day and note when each area gets sun.

Water Access

You will water often in summer. Place beds within easy reach of a hose or plan for drip irrigation or soaker hoses.

Level Ground and Drainage

A fairly level spot makes building easier and helps water soak in evenly. Avoid low areas where water pools after rain.

Convenience

A bed near the kitchen door gets more attention than one at the far end of the yard. You are more likely to harvest, weed and spot problems early when you walk past it every day.

Step 2: Decide on Size and Height

Width

Keep beds no wider than about 4 feet if you can reach from both sides, or about 2 to 3 feet if the bed is against a fence or wall. You should be able to reach the center without stepping into the bed, because stepping compacts the soil.

Length

Length is flexible. Common sizes are 4 by 4 feet, 4 by 8 feet and 3 by 6 feet. A 4-by-8-foot bed is a popular starting point because lumber often comes in 8-foot lengths.

Height

• 6 to 12 inches: Enough for most vegetables when placed over loosened native soil.
• 12 to 18 inches: Better for poor or compacted ground and easier on the back.
• 24 inches and higher: Easier access for people who prefer not to bend, but requires much more soil to fill.

Paths

Leave paths at least 18 to 24 inches wide, or wider if you need room for a wheelbarrow or mobility aids.

Step 3: Choose Your Materials

Untreated Cedar or Redwood

Naturally rot-resistant and attractive. More expensive than pine but lasts longer.

Untreated Pine or Fir

Inexpensive and easy to find, but it will rot faster, often within a few years in contact with moist soil.

Pressure-Treated Lumber

Modern residential pressure-treated wood no longer uses the arsenic-based treatment that was phased out for residential use in the early 2000s. Many gardeners use newer treated lumber, while others prefer to avoid it or line it. If you are unsure, choose naturally rot-resistant wood or another material.

Galvanized or Coated Metal

Metal beds are long-lasting and come in many sizes and colors. They can warm up in hot sun, which may matter in very hot climates.

Stone, Brick or Concrete Block

Durable and permanent. Some gardeners avoid old reclaimed materials of unknown origin.

Kits

Raised bed kits make assembly easy and come in wood, metal and composite. Compare thickness, corner hardware and dimensions before buying.

Avoid

• Old railroad ties, which are treated with creosote
• Tires
• Wood of unknown origin that may have been treated with older preservatives

Step 4: Prepare the Ground

1. Remove grass and weeds where the bed will sit, or smother them with cardboard (remove tape and labels first).
2. Loosen the native soil with a garden fork so roots can grow deeper.
3. Add hardware cloth across the bottom if burrowing animals like gophers or voles are common in your area.
4. Avoid weed fabric directly under beds for vegetables in most cases; roots benefit from reaching native soil.

Step 5: Fill the Bed

Raised beds need loose, rich soil that holds moisture but drains well.

A Simple Mix

Many gardeners use a blend of roughly:

• Topsoil or a quality garden soil for structure
• Compost for nutrients and organic matter
• An aeration material such as fine bark, which some gardeners add for drainage

Some suppliers sell a ready-made raised bed mix by the bag or in bulk. For larger or taller beds, buying in bulk is usually far cheaper than bags.

Filling Deep Beds

For very tall beds, some gardeners fill the bottom with logs, branches and leaves (a method sometimes called hugelkultur) and put quality soil on top. Expect the material to settle over time.

Calculating How Much Soil You Need

Multiply length × width × depth in feet to get cubic feet. A 4-by-8-foot bed that is 1 foot deep holds 32 cubic feet. Divide by 27 to get cubic yards, the unit bulk suppliers use.

Make Your Own Compost

Over time, you can top up beds with homemade compost. See our guide to composting at home.

Step 6: Plan the Layout

Square-Foot Style Planting

Divide the bed into a grid of 1-foot squares and plant a set number of plants per square based on size. For example, one tomato might take one or more squares, while radishes or carrots can fit many per square.

Put Tall Plants on the North Side

In the Northern Hemisphere, place tall crops like tomatoes, pole beans and trellised cucumbers on the north side so they do not shade shorter plants.

Leave Room for Support

Install trellises and cages at planting time.

Sample 4-by-8 Beginner Layout

Section	Plants
North end	2 tomato plants with cages, basil between
Middle	Bush beans, peppers
South end	Lettuce, radishes, carrots, onions
Edges	Marigolds or nasturtiums, herbs

See our companion planting guide for more ideas.

Step 7: Plant and Care

When to Plant

Check your area’s average last frost date. Cool-season crops like lettuce, peas and radishes can go in before the last frost, while warm-season crops like tomatoes, peppers and squash should wait until after it, when soil has warmed. Your local cooperative extension service publishes planting calendars.

Watering

Raised beds drain faster than in-ground beds and may need more frequent watering. Water deeply at the base of plants rather than lightly on leaves. Mulch helps keep soil moist.

Mulch

Straw, shredded leaves or fine bark mulch helps retain moisture, suppress weeds and moderate soil temperature.

Feeding

Add compost each season. Many vegetables also benefit from a balanced fertilizer; follow the label directions.

Frequently Asked Questions

How deep should a raised bed be for vegetables?

Many vegetables grow well in beds 8 to 12 inches deep over loosened native soil. Deep-rooted crops and poor native soil benefit from deeper beds.

Should I put anything in the bottom of a raised bed?

Cardboard can smother grass, and hardware cloth can keep out burrowing animals. Avoid plastic, which blocks drainage.

Can I use bagged potting mix in a raised bed?

Potting mix is designed for containers and can be expensive for large beds. A raised bed or garden soil blend with compost is usually more cost-effective.

How long do wooden raised beds last?

It depends on the wood, climate and moisture. Cedar and redwood generally last longer than pine.

Do raised beds need to be refilled?

Soil settles and breaks down over time. Top up with compost each year.

The Bottom Line

Start with one or two beds in a sunny, convenient spot. Keep them narrow enough to reach the center, choose durable safe materials, fill them with a quality soil and compost blend and plan a simple layout with tall plants on the north side. A well-built raised bed can make your first vegetable garden a success and grow with you for years.

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Editorial note: Backyard Bloomer is independent and reader-supported. This guide is based on research into manufacturer documentation, published specifications and widely accepted best practices; we have not been paid to mention any product. If we add affiliate links in the future, they will be clearly disclosed per our Affiliate Disclosure.