Although traditionally planted in mounds, I wanted to adapt the Three Sisters method to square-foot gardening in raised beds, which is how most of my garden is planted. I’m sharing the spacing, planting times, and tips, along with what I learned by trying the Three Sisters method in raised beds.

What we’ll cover:

• How to Plant a Three Sisters Garden in a Raised Bed (Layout)
• Best Varieties for Your Three Sisters Garden
• When to Plant Your Three Sisters Garden
• Growing Tips for Your Three Sisters Raised Bed Garden
• Harvesting Tips & Observations from My Garden
• Quick Summary

How to Plant a Three Sisters Garden in a Raised Bed (Layout)

I planted my Three Sisters garden in three of my 4×8 raised beds. Here’s the layout I used successfully:

• Corn: Two rows down the center of each bed, spacing roughly 8-12 inches apart (about 12–16 stalks per bed). Initially, I planted corn seeds directly, but found the soil was still too cool, so the seeds didn’t sprout. Using transplants for the spring planting was much more successful.
  
• Beans: Once the corn was 6 inches to a foot tall, I planted one pole bean seed at the base of each corn stalk (16 bean plants per bed). Use bean transplants if the soil is still cool.
  
• Squash: I planted two squash plants on each of the long sides of the bed (four squash plants total). The end of my beds already had flowers and roses, so the squash plants occupied the side spaces. Using squash transplants was helpful if the soil was still cool.
  

If you are gardening in containers, consider trying a Three Sisters grow bag garden instead.

Best Varieties for Your Three Sisters Garden

These varieties grew well for me and are reliable performers:

• Corn: Silver Queen
  
• Beans: Rattlesnake and Kentucky Wonder Pole Beans
  
• Squash: Black Beauty Summer Squash, Waltham Butternut, or Block Party F1 Butternut (a newer hybrid variety)
  

When to Plant Your Three Sisters Garden

General Planting Guidelines (most climates):

• Corn: Plant seeds or transplants once the danger of frost has passed and nighttime temperatures reach at least 55°F (13°C)—typically May in cooler climates. Learn how to check the soil temperature in this guide.
  
• Pole Beans: Plant seeds or transplants around corn stalks when the corn is about 6–12 inches tall.
  
• Squash: Plant seeds or transplants roughly two weeks after beans sprout, or when beans are several inches tall. This gives corn and beans a head start and prevents squash from overwhelming them.
  

Low Desert (Arizona) Specific Planting Windows:

• Spring Planting: Begin planting February 15 – March (you may need to use transplants if the soil is still cool).
  
• Monsoon Planting: July – August (the soil will be warm enough for direct seeding).
  

Experiment to determine the timing that works best in your garden.

Vegetable, Herb, and Fruit Planting Guide for the Low Desert of Arizona

The ultimate resource for gardeners in arid regions with hot summers and mild winters—designed specifically for the low desert of Arizona.
It features information on how and when to start seeds indoors and when to transplant them outside for nearly 100 different fruits, vegetables, and herbs.

See it in my shop

Growing Tips for Your Three Sisters Raised Bed Garden

Here are some tips that helped me get the most from my raised-bed setup:

• Soil preparation: Corn is a heavy feeder. Before planting, I amended my raised beds with compost and plenty of worm castings. Learn more about the best soil for raised beds.
• Fertilizing: I fertilized corn plants twice during the growing season with AgroThrive fertilizer. It’s organic, easy to use, and effective.
• Watering consistently: Raised beds dry out quickly. Regular, deep watering is crucial. Read my tips on how to water raised bed gardens.
• Sunlight: Choose a location with full sun (at least 6–8 hours daily). I used shade cloth over part of my garden once daytime temperatures topped 90°F.
• Managing beans: Beans climb rapidly. Keep an eye on the vines. Unwrap any that tangle around the corn ears or the tassles. You can top the vine to keep it from growing taller than the corn.
• Supporting vines: Winter squash vines need room to grow. I planted winter squash in the raised bed next to my arch trellises, allowing the vines to climb and spread.

If you’re new to square-foot planting, check out my tips for growing a square-foot garden.

Harvesting Tips & Observations from My Garden

• Harvesting: Beans and summer squash were ready to harvest first, followed by corn. The bean harvest started off slow but picked up quickly as the corn matured.
• Pollination: Pollination was about 80% successful (yay!) with minimal hand-pollination effort.
• Beneficial insects and pests: I was happy to see ladybugs and lacewings, but surprisingly few pests. Normally, I see worms when growing corn, but not this year. The beans showed whitefly damage (especially lower next to the soil), but it didn’t seem to hinder production or get out of hand.
• Supporting corn stalks: Most corn stalks remained upright, supported by bean vines, but a few fell due to the wind. To keep them upright until harvest, I used wooden stakes and coated wire.

What’s next? After removing the corn, I left several pole bean plants in place and planted okra in its place. I’m curious to see if the beans will climb the okra and continue producing—a fun experiment in companion planting and crop succession. The winter squash should continue to grow well; it has several fruits on the vine and is happily climbing the trellis.

Quick Summary

Growing a Three Sisters garden in raised beds was productive and surprisingly easy. I harvested an impressive amount of corn, beans, and squash from a relatively small space.

Using transplants early in the season gave the garden a helpful head start while waiting for the soil to warm. Direct seeding may be more successful during the monsoon planting when the soil is warmer. I wouldn’t adjust the spacing—it worked well—but I may adjust the timing of planting beans next time to prevent them from tangling with the corn tassels before pollen is released.

If you’ve been considering planting a Three Sisters garden, it’s definitely worth trying. Feel free to comment below with your experiences or questions.

The post How to Grow a Three Sisters Garden in Raised Beds appeared first on Growing In The Garden.

Article Outline:

• Why Soil Quality is Essential for Raised Beds
• The Best Soil for Raised Bed Vegetable Gardening is Mel’s Mix
• What is in Mel’s Mix?
• Arizona Worm Farm Raised Bed Mix
• Advantages of Using Mel’s Mix for Raised Bed Vegetable Gardening
• How to Combine the Ingredients for Mel’s Mix
• Maintaining Your Raised Bed Soil

Why Soil Quality is Essential for Raised Beds

Raised beds offer numerous advantages, but success depends mainly on the soil quality you use. Here’s why soil quality is so important:

• Better Drainage: Good raised bed soil improves drainage while ensuring that plants still get the needed moisture.
• Root Growth: Loamy, well-aerated soil encourages roots to spread and access nutrients.
• Nutrient Availability: Nutrient-rich soil is vital for healthy plant growth and productive harvests.
• Soil Structure: The right blend of organic matter and aeration helps create a loose, crumbly texture that plants thrive in.

Good soil is the foundation—but layout matters too. See how my garden beds, containers, and fruit trees fit together in a cohesive design.

If you’re wondering what the best soil for raised bed vegetable gardening is, the answer is simple—Mel’s Mix.

The Best Soil for Raised Bed Vegetable Gardening is Mel’s Mix

I didn’t come up with this mix; we can thank Mel Bartholomew, the author of Square Foot Gardening, for developing a simple, effective soil blend for raised bed gardening. After reading his book in 2008, I followed his advice for making Mel’s Mix, which he calls “the most important, productive, essential, necessary, critical” ingredient for square-foot gardening success—and it worked!

Mel’s Mix is a tried-and-true solution for raised beds, providing an ideal balance of moisture retention, aeration, and nutrient availability.

What is in Mel’s Mix?

Regular garden soil is too dense for raised bed gardening. Mel’s Mix solves that problem by combining compost, coco coir, and vermiculite to keep the soil light and airy. This blend provides excellent drainage and a healthy environment for plant roots. Here’s the breakdown:

• One part compost: You can make your compost, or if you live in Arizona, the compost from Arizona Worm Farm is a great option. If you use bagged compost, it’s best to mix several different types.
• One part coco coir: A sustainable alternative to peat moss that retains moisture and improves soil structure.
• One part vermiculite or perlite: These materials help with soil aeration and moisture retention.
• 3-5% worm castings: About 1/3 gallon per cubic foot adds beneficial microbes and nutrients. Make your own with in-bed vermicomposting bins or purchase them locally if possible.
• 1/2 cup basalt dust per cubic foot adds trace minerals that benefit plant health.

Depending on your needs, you can also adjust the mix by using up to 50% compost and 25% each of vermiculite and coco coir.

Arizona Worm Farm Raised Bed Mix

In the Fall of 2020, Arizona Worm Farm began offering a ready-made soil mix called “Growing in the Garden Raised Bed Mix.” This mix contains the perfect blend of compost, coco coir, vermiculite, worm castings, and basalt dust. It’s available by the bag or yard. This premixed soil is an easy, convenient option for anyone looking for the best soil for raised beds in the Phoenix area.

Advantages of Using Mel’s Mix for Raised Bed Vegetable Gardening

Mel’s Mix offers several distinct advantages that make it the best choice for raised bed vegetable gardening:

• Simplified Drainage: The combination of vermiculite and coco coir ensures excellent water retention while preventing waterlogging. The soil absorbs moisture, and excess moisture easily drains away when saturated. You can’t overwater with this mix!
• Easy Seed Germination: Seeds germinate quickly in this light, airy mixture, making it ideal for direct sowing in raised beds.
• Minimal Weeds: One of Mel’s Mix’s biggest benefits is its weed-free nature. Since the soil stays light and loose, weeds have difficulty establishing themselves.
• Oxygen for Roots: Healthy roots need both oxygen and water. Mel’s Mix’s light texture allows plant roots to access both, leading to vigorous growth.

How to Combine the Ingredients for Mel’s Mix

There are a couple of ways to mix the ingredients for the best soil for raised bed gardening:

1. Batch Mixing on a Tarp: Spread a tarp on the ground and combine the compost, coco coir, and vermiculite in batches. Once everything is mixed, dump the contents into your raised bed and water thoroughly.
2. Layering in the Raised Bed: You can layer the ingredients directly in the raised bed, mixing well after each addition. This “lasagna style” approach is convenient and works just as well.

It’s a good idea to mix up a little extra of Mel’s Mix to fill containers or top off your raised beds throughout the season. Store it in a large, lidded garbage can for easy access.

Maintaining Your Raised Bed Soil

Over time, the soil level in your raised beds will decrease as the organic matter breaks down. Adding more compost each time you plant is important to keep the soil level topped up and maintain its nutrient content.

• Compost: As the compost decomposes, it enriches the soil with essential nutrients. Keep adding compost to your raised beds with each planting cycle to maintain healthy, nutrient-rich soil. For more information on how to make your compost, check out my composting guide.
• No Need to Replace Coco Coir and Vermiculite: Unlike compost, coco coir and vermiculite don’t break down as quickly, so you won’t need to replenish these components each season. Just focus on adding fresh compost.
• Add in-bed vermicomposting bins to your beds. Worms break down food scraps and create nutrient-rich worm castings right in your garden bed. Read this in-bed vermicomposting guide to learn how to add these bins to your beds.

Using the right mix and maintaining your soil over time ensures that your raised beds remain productive for years. Whether you mix your own or opt for a premade option like Arizona Worm Farm’s Raised Bed Mix, getting the best soil for raised bed vegetable gardening will give you healthier plants, fewer weeds, and bigger harvests.

When you are ready to build new beds, learn step-by-step how to fill a raised bed with the right soil and amendments.

For more soil resources on my blog, read these articles:

• How to Prepare Your Soil For Planting
• How to Refresh Old Potting Soil
• Soil Testing: When and How to Test Your Soil

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I followed Mel’s advice and agree that square foot gardening is the best way to get started and have a thriving home garden. In this post, I’ll share five essential tips to help you have a productive and beautiful square foot garden.

1. Start small to have a successful Square Foot Garden

When you begin gardening, it’s easy to get overwhelmed. But, if you start small, it is easier to succeed. Then, as you gain experience, expand your garden.

One 4’x4′ or 4’x 8′ (1.2m x 1.2m or 1.2m x 2.4m) raised bed is a good starting point. You can grow a surprising amount in this size space. Although Mel recommends beds be 6 inches (15 cm) deep, I’ve had the best success with beds between 12-18 inches (30-45 cm) deep.

I use the Deep Root Cedar Beds from Gardener’s Supply and the Metal Raised Garden Bed with Garden Grids from Garden in Minutes in my garden.

Starting with one bed is manageable, and you can learn as you grow. Later, as your experience increases, you can add more beds.

This 4’x 8′ (1.2m x 2.4m) raised bed has three varieties of peppers, 4 different herbs, carrots, spinach, lettuce, cabbage, onions, flowers, and more.

2. Follow the directions to have a successful Square Foot Garden

As you read the book All New Square Foot Gardening, Mel gives specific advice about:

• The importance of using a grid
• Proper planting spacing guidelines
• Optimal sizes for raised beds
• Distances between beds
• Which type of soil to use

Here are a few important directions to follow to have a thriving Square Foot Garden:

Use a grid in your square foot garden.

I used to have raised beds with permanent grids and some without. Here’s what I learned: the ones with grids utilize the space much more efficiently. Also, I quickly filled an empty square (see tip #5 below) with seeds or transplants in my gardens with grids. Now, all of my raised beds have grids.

I am not the most naturally-organized gardener, but here’s my secret — the permanent grids give me a framework and guidelines to be organized. I love them!

I use watering grids from Garden in Minutes for the permanent grids in my garden. The benefits of using the Garden Grid™ from Garden In Minutes include:

• The grids are prominent and easy to see. 
• Assembly is simple; the garden grids come in preassembled sections that press together by hand in seconds.
• At the end of each season, lifting the grid off the bed and adding compost to fill the beds is easy. With my previous grids made of wood, it was challenging to add compost because the grids were screwed into the beds. 
• Each square is watered evenly with 16 water streams, which helps seed germination.

Follow the plant spacing guidelines. 

Planting the recommended amounts allows you to utilize all the space in the beds without overcrowding. This post shares the recommended plant spacing for square foot gardens.

Free Square Foot Gardening Downloads

Follow the garden bed and aisle size guidelines.

Square foot gardening recommends beds no wider than four feet with at least three feet between each bed. It may seem like a lot of space between beds, but plants thrive in square-foot gardens and will quickly fill in the spaces. 

Answer to frequently asked question: The white buckets in my beds are in-bed vermicomposting bins. Learn more about in-bed vermicomposting in this blog post.

The guidelines in square foot gardening helped me design my garden. I share more raised bed garden design tips in this blog post.

Use the best soil for raised bed gardens.

A fundamental principle behind the success of square foot gardening is the soil Mel Bartholomew developed.

“Years of experimentation led Mel Bartholomew to a simple mixture of equal parts peat moss, coarse vermiculite, and blended compost as the perfect growing medium for his revolutionary gardening method. Mel was forever experimenting and adapting his method, but although he recognized that there were circumstances under which gardeners might need to alter the ingredients in the growing medium, he never, ever found anything that could fully substitute for the original Mel’s Mix formula.”

All New Square Foot Gardening, page 125.

Use the correct blend of soil, and don’t forget to add fresh compost each time you plant.

• 1/3 vermiculite or perlite
• 1/3 coconut coir (triple washed is best) or peat moss
• 1/3 compost (several different types are best)

If you live in the Phoenix valley, I worked with Arizona Worm Farm to develop a modified Mel’s Mix that is well-suited for growing in the low desert of Arizona’s harsh conditions. Read this post for more information about the best soil for raised bed gardens. 

3. Use vertical space to have a successful Square Foot Garden

There never seems to be enough space in the garden; fortunately, there’s a simple solution – growing vertically. Vertical gardening has several benefits, including:

• Saves space and adds additional growing room.
• Many vining crops grow best when grown vertically.
• Adds visual appeal to the garden.
• Growing crops vertically provides additional sunlight and airflow for plants.
• Pests and diseases are often easier to spot when growing crops vertically rather than sprawling on the ground.

There are several ways to grow vertically, such as ladders, ladder mesh trellises, etc., but no matter how you do it, use the vertical space in your garden!

I used square-foot gardening principles to plan and space my Three Sisters garden in raised beds—it worked surprisingly well, even for corn.

I utilize many different ways of growing vertically in my garden. Learn more here.

Looking for ways to add vertical space to your garden? This post shares 10 of my favorite ideas.

In this blog post, find more ways to add vertical space to your garden.

4. Follow a planting guide for your area

Each crop has a preferred growing temperature. Some prefer cooler weather and tolerate a slight frost; others need warmer weather to grow well and would die in frosty conditions. Plants are happiest and grow best when planted at the ideal soil temperature and growing conditions.

Planting crops at the right time is a crucial part of gardening. However, the best time to plant varies significantly by region. A big part of gardening success is learning the unique growing conditions of your area.

Find a reliable planting guide for your area, follow it using square foot gardening principles, and you will be successful. Read this post to help find a local planting guide for your area.

For example, where I live in Arizona, our planting dates differ significantly from other parts of the country. I use this Arizona Vegetable Planting Guide.

Perpetual Vegetable, Fruit & Herb Calendar shows you when to plant vegetables in the low desert of Arizona and whether to plant seeds or transplants. See it in my shop.

5. When a square opens up, plant something

The last of the 5 tips for a successful square foot garden seems simple, but it is essential. When you follow correct square-foot gardening principles, you will harvest plants from squares and have open space that might go unnoticed in less-organized gardens. An empty square is an invitation to plant!

A few steps and you’re ready to plant in your empty square:

Remove the spent plant by cutting it at the base of the plant. (The roots will add organic matter to the soil.)

Add a layer of fresh compost to the top of your soil.

Check your planting guide to decide what to plant.

Plant seeds or transplants in the square!

Use this tool to space seeds perfectly in your square foot garden. 

Mel Bartholomew’s book, All New Square Foot Gardening, made my list of “5 Best Gardening Books“. Find out which other books make the cut in this post. 

Free Square Foot Gardening Downloads

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The first gardening class I attended was about square foot gardening. I soaked it all in and then bought Mel Bartholomew’s “Square Foot Gardening” book. One of the concepts I loved was the simplicity of plant spacing in square foot gardens. 

How do you space plants in square foot gardening

A key factor in being successful with plant spacing in square foot gardening is adding a grid to your garden. Mel Bartholomew said, “If your garden box doesn’t have a grid, it’s not a Square Foot Garden.”  His book also emphasized that the grids be “prominent and permanent”. I have come to see the wisdom in this tip.

Why use grids for plant spacing in square foot gardens?

In the past, I had some garden beds with grids and some without grids. After using both, I can say the ones with grids have several advantages: 

• Garden beds with planting grids utilize space more efficiently by eliminating the need for rows.
• Using a garden grid helps you see exactly where there is space to plant. When I see an empty square, I’m quick to fill it with seeds or plants. In the past, empty spots in beds without grids were often left empty.
• Garden grids help an unorganized gardener (like me) be more organized – I don’t have to worry about straight rows. 

• Following plant-spacing guidelines with garden grids allows for proper spacing between plants. This prevents overcrowding, which causes plants to compete for limited resources of sun, water, and nutrients. 
• Using garden grids in your garden beds allows for a system of polyculture (several compatible plants growing together) as opposed to monoculture (row after row of the same crop) which is better for pest and disease prevention.

Free Square Foot Gardening Downloads

Which type of garden grids should I use for square foot gardening?

Once I realized the benefits of using grids with square foot gardening, I added grids to all of my raised beds. My favorite way to add grids for square foot gardening is with the Garden Grid™ from Garden In Minutes.

The benefits of using the Garden Grid™ from Garden In Minutes include:

• The grids are prominent and easy to see. 
• Assembly is simple; the garden grids come in preassembled sections that press together by hand in seconds.
• At the end of each season, it’s easy to lift the grid off of the bed to add compost to fill the beds. With my previous grids made of wood, it was difficult to add compost because the grids were screwed into the beds. 
• Each square is watered evenly with 16 water streams, which helps seed germination.

How do I know how many seeds or plants to put in each square?

Now for the fun part – adding plants to your square foot garden. To calculate how many plants or seeds to plant per square, look at the back of your seed packet. Ignore the space between rows, but pay attention to how much space is needed between plants.

For example:

3″ plant spacing = plant 16 in each square.

4″ plant spacing = plant 9 in each square.

6″ plant spacing = plant 4 in each square.

12″ plant spacing = plant 1 in each square.

Some plants (such as melons, large squash, and tomatoes) require more than one square.

Wondering how to space corn, beans, and squash in a small garden? I share the exact layout I used in this Three Sisters garden in raised beds using square-foot gardening principles.

Use this tool to space seeds perfectly in your square foot garden. 

Why is plant spacing important in square foot gardens?

Follow the plant-spacing guidelines. Planting the recommended amounts allows you to utilize all the space in the beds without overcrowding. Proper spacing ensures adequate airflow for plants.  

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