Enjoy gardening at ease with our 100-Day Sproutbox Garden Guarantee! If you're not satisfied in the first 100 days, send it back to us and we will issue you a full refund.
Why Gardeners Love the 17" Tall Extension Kit Add-on:
Expand Your Growing Space: Add an extra 1.5 feet to your 17” tall 9-in-1, L-shaped, or U-shaped garden beds, giving you more room to grow without the need for additional beds. Perfect for those who want to make the most of their garden setup.
Seamless Integration: Designed specifically for Sproutbox beds, this extension kit matches the durability and finish of your existing bed. It’s easy to install and blends in perfectly for a clean, cohesive look.
Everything You Need Included: Each kit comes with panels, bracing rods, stainless steel hardware, extra rubber edging, and an easy-to-follow instruction guide. All the essentials for a quick and hassle-free extension.
Built to Last: Made from corrosion-resistant Magnesium-Aluzinc Steel to match the quality of your garden bed, this extension kit is just as durable, holding up season after season.
Width: 3 inch
Length: 21 inch
Height: 18 inch
Weight: 8 Lbs
Add Postal Code and they will receive an estimated time of delivery.
Dimensions
FAQs
How many Extension Kits can I add to my garden bed?
The possibilities are almost endless when adding length to your garden. We've had customers create gardens well over 20 feet (we recommend not going beyond 3.5' in width, when extending the length of your garden).
I’ve gardened for over 30 years and never had such an abundant harvest. I couldn’t be happier with my new beds! The 17” depth is easy to work, keeps the rabbits out, and ensures deep roots and easy watering.
Val A.
Verified Purchase
They are very sturdy, easy to put together with simple instructions and great packaging. They're also made with very high quality materials.
Clara N.
Verified Purchase
We installed 3 sprout boxes in the 17 inch rectangular configuration. They are full of beautiful top soil and are seeded with winter greens in our new greenhouse. They are sleek and will work great through the Seasons in the greenhouse.
Cheryl L.
Verified Purchase
Love them, just the right height to work at an added bonus, the rabbits can’t reach the veggies! Plan to add a few more this fall.
Rebuild or expand anytime your layout, your rules.
Why Gardeners Choose Sproutbox Beds.
Practical benefits that make every season easier, safer, and more productive.
Modular
Each garden kit comes with multiple panels for complete autonomy of your dream garden set-up. The modular design gives you endless configurations when buying multiple sets.
Longevity
The thick (0.6mm) specially coated steel is what sets us apart. Your garden kit is designed to last 3-7x longer than regular galvanized steel and has a lifespan up to 20 years.
Safe for kids
Commercial grade rubber lines the top of the garden providing a comfortable place to rest arms and hands on, while also making it safe for kids.
Sustainable
The steel is 100% recyclable and made using a green manufacturing process.
Safe for Veggies
Our specially designed steel provides safe gardening for all your vegetables. With typical soil acidity levels hovering around neutral, there should be no concern with leaching metals into your soil.
Comfortable Roots
Take control of your soil health with up to 32” of fresh fertile earth. The generous depth provides ample room for strong roots and healthy plants.
Customer Reviews
Overall rating: 4.9 / 5 from 80 reviews.
Replacing existing beds requires extensions plus a 9-in-1 to match as close as possible the original dimensions. This is the eighth bed that I successfully rebuilt. The hardware provided allows completion usually within six inches of the old wooden structure.
Store owner replied:
Congratulations on completing your eighth bed rebuild and matching the dimensions of your original setup so closely. Enjoy your newly rebuilt garden space this growing season. -Sproutbox Garden Team
Store owner replied:
We're so pleased to hear how much you appreciate the flexibility of our 17” Tall Extension Kit and its ability to expand your planting real estate. It's wonderful to know that you found the extension process easier than expected, leading to much more planting real estate. -Sproutbox Garden Team
I am very grateful for the size exchange. Thanks to Susan, my garden looks perfect and beautiful the way I wanted it.
Store owner replied:
Thanks for the 5 stars! – The Sproutbox Garden Team
The boxes are great! Set up was easy and they are beautiful and the perfect size with the extension kits. Thank you so much for making such a great Canadian product!
Store owner replied:
We truly appreciate your feedback and support. Happy growing! – The Sproutbox Garden Team
As you can see, a work in progress! My sister and I put it together. Took a bit longer than your suggested 40 minutes - but hey, my sister is 76 years and I am 83! So we did good. And still friends!
It is perfect for me, will send more pictures as I go along.
Thank you.
Store owner replied:
It’s customers like you that make what we do so rewarding—thank you! – The Sproutbox Garden Team
A great addition to the garden bed system we already love. The modular design made it easy to customize the layout, and the extension integrated seamlessly with our existing beds. High-quality construction and a smart, flexible solution for expanding our garden this season! :)
Store owner replied:
Your review made our day—thanks for your trust and support! – The Sproutbox Garden Team
I purchased two 9 in 1's and realized that they needed to be slightly longer to fit in the space I have placed them. They were simple to add and I am very happy with how they look.
Store owner replied:
Thank you for growing with us! We’re excited to be part of your gardening journey. -Sproutbox Garden Team
I had not yet assembled my 17" 9 in 1 kit so it was very easy to add the expansion kit when I assembled the two together. I think it would be a bit difficult to add an expansion kit once the main bed is already assembled of course depending on the location. Mine are on a grass space that I dug out to allow for the slope of my property so adding an expansion kit would be quite an undertaking to change everything. Overall, though, I'm very glad that I purchased the expansion kit before the main bed was assembled.
Store owner replied:
Thank you for the review and the video, your garden is stunning!- The Sproutbox Team.
We purchased the 17" 9-in-one kit with the extension pieces. Very impressed with how easy it was to assemble, and how sturdy it is. We are using it to replace an older bed that we had built from boards, which had begun to fall apart. We're confident the Sproutbox bed will remain in good shape well into the future, and expect to replace the rest our existing beds with them over time. Thanks for the great solution!
Store owner replied:
Thank you for the great review and the video. Say hello to Lucy! We look forward to growing with you and would love to see updated photos of your Sproutbox's thriving.- The Sproutbox Team.
Love the everything I have ordered from Sproutbox. Easy assembly and look great!
Store owner replied:
Thank you for the video! We are so happy you love your sproutboxes! 🌱💚 —thanks for growing with us!
Love the product. This time we added a couple more 9 in 1s and expanded their width either double or triple plus doubled a couple of others we had got last year. This has effectively doubled the capacity (we previously had six nine in ones) of the entire garden. Soil is now in place and planting has commenced.
Great experience start to finish. Sproutbox staff were so helpful helping me configure what I needed to order for my 9.5 foot x 5 foot box.
Setting up couldn’t have been easier and now I’m ready to get growing!
Thanks Sproutbox,
Jane
Store owner replied:
This is great to hear! Thank you for the 5 star review!
-Sproutbox Garden Team
My install in progress!
I bought 2 Modular 9 in 1 kits, plus 2 sets of round ends, and the extension kit so now I have:
One 8 x 2'
One 6.5 x 2'
One 5 x 2'
One 3.5 x 2'
SproutBox were marvellous in sorting out an error in shipping, customer service second to none, and very high quality planters.
Store owner replied:
Your garden looks so good! Thank you so much for sharing!
-Sproutbox Garden Team
I have 3 garden beds to replace.
I thought about going back to wood but once I started ripping out the old beds I had to give my head a shake. Carpenter ants, rot and the expense of wood stopped me from going that route.
I researched Sproutbox Garden and I have no regrets.
Great product with a modern look.
Love these boxes. Easy to assemble and move into place. Tons of info on website to help you fill them. Have 7 boxes filled with potatoes, onions, beets and lettuce.
Store owner replied:
We appreciate your kind review—thank you for choosing Sproutbox Garden beds!
-Sproutbox Garden Team
My garden bed was a cinch to put together. The extension kit has all the support rods you would need depending on the bed size you chose. Great quality and looks great too!
Store owner replied:
We love hearing this! Thanks for taking the time to leave a review.
–Sproutbox Garden Team
i love the sprout box it is high enough that the feral cats can not get in and mess up what i planted.
i have one box with plants in front of my greenhouse and they are growing very well.
There will be a 2nd box going up this week as soon as some construction happens on the house near where the new box will be. That way i can keep herbs and veg going till late fall with a cover , and it is much easier to weed than ground level. Danella Hesler
What are Sproutbox Garden raised metal beds made from?
All our raised beds are made of the top rated steel for gardens, Aluzinc- Magnesium Steel.
Our steel is Japanese designed and made for adverse and extreme conditions. Our thick (0.6mm) corrugated steel with specialized exterior coating makes it the best choice on the market for garden applications. Superior to galvanized and aluzinc steel in regards to corrosion, durability, and lifetime.
What makes Sproutbox Garden the ultimate choice for raised garden beds?
Sproutbox Garden stands out with its unbeatable combination of longevity, versatility, and safety. Our specially coated steel beds are industry-leading in strength and durability, ensuring your garden thrives for years. Our modular design allows for endless creativity, and with child and pet-friendly rounded corners and rubber edging, everyone can safely enjoy the garden.
What is the best raised garden bed?
When considering a brand or type of raised garden bed, three words are at the top of everyone's list. Longevity, versatility, and safety. Sproutbox Garden specializes in all three of these categories. We make our raised beds out of Aluzinc-Magnesium Steel, which is leading the industry in strength and durability. Our modular design provides autonomy and flexibility in the building process. Sproutbox products are safe for kids and pets with their rounded corners and commercial grade rubber edging that lines the top of each bed. Moreover, our specially designed Steel is safe for veggies, with no concern of metal leaching into the soil.
Why should I choose raised bed gardening if I’m in Canada?
Raised bed gardening empowers you to control your garden's growing conditions, like soil type and fertilizers, ensuring optimal growth for your favourite fruits and vegetables. Plus, it's a fulfilling hobby that lets you enjoy the great outdoors and savour the pride of harvesting fresh produce straight from your garden.
Is it safe to grow vegetables in Steel raised garden beds?
Absolutely! Our specially designed Steel is safe for gardening as it requires acidity to break down the zinc coating, which is minimal in neutral garden soils. Additionally, zinc is an essential plant nutrient and a natural part of the soil.
Replacing existing beds requires extensions plus a 9-in-1 to match as close as possible the original dimensions. This is the eighth bed that I successfully rebuilt. The hardware provided allows completion usually within six inches of the old wooden structure.
Store owner replied:
Congratulations on completing your eighth bed rebuild and matching the dimensions of your original setup so closely. Enjoy your newly rebuilt garden space this growing season. -Sproutbox Garden Team
Store owner replied:
We're so pleased to hear how much you appreciate the flexibility of our 17” Tall Extension Kit and its ability to expand your planting real estate. It's wonderful to know that you found the extension process easier than expected, leading to much more planting real estate. -Sproutbox Garden Team
I am very grateful for the size exchange. Thanks to Susan, my garden looks perfect and beautiful the way I wanted it.
Store owner replied:
Thanks for the 5 stars! – The Sproutbox Garden Team
The boxes are great! Set up was easy and they are beautiful and the perfect size with the extension kits. Thank you so much for making such a great Canadian product!
Store owner replied:
We truly appreciate your feedback and support. Happy growing! – The Sproutbox Garden Team
As you can see, a work in progress! My sister and I put it together. Took a bit longer than your suggested 40 minutes - but hey, my sister is 76 years and I am 83! So we did good. And still friends!
It is perfect for me, will send more pictures as I go along.
Thank you.
Store owner replied:
It’s customers like you that make what we do so rewarding—thank you! – The Sproutbox Garden Team
A great addition to the garden bed system we already love. The modular design made it easy to customize the layout, and the extension integrated seamlessly with our existing beds. High-quality construction and a smart, flexible solution for expanding our garden this season! :)
Store owner replied:
Your review made our day—thanks for your trust and support! – The Sproutbox Garden Team
I purchased two 9 in 1's and realized that they needed to be slightly longer to fit in the space I have placed them. They were simple to add and I am very happy with how they look.
Store owner replied:
Thank you for growing with us! We’re excited to be part of your gardening journey. -Sproutbox Garden Team
I had not yet assembled my 17" 9 in 1 kit so it was very easy to add the expansion kit when I assembled the two together. I think it would be a bit difficult to add an expansion kit once the main bed is already assembled of course depending on the location. Mine are on a grass space that I dug out to allow for the slope of my property so adding an expansion kit would be quite an undertaking to change everything. Overall, though, I'm very glad that I purchased the expansion kit before the main bed was assembled.
Store owner replied:
Thank you for the review and the video, your garden is stunning!- The Sproutbox Team.
We purchased the 17" 9-in-one kit with the extension pieces. Very impressed with how easy it was to assemble, and how sturdy it is. We are using it to replace an older bed that we had built from boards, which had begun to fall apart. We're confident the Sproutbox bed will remain in good shape well into the future, and expect to replace the rest our existing beds with them over time. Thanks for the great solution!
Store owner replied:
Thank you for the great review and the video. Say hello to Lucy! We look forward to growing with you and would love to see updated photos of your Sproutbox's thriving.- The Sproutbox Team.
Love the everything I have ordered from Sproutbox. Easy assembly and look great!
Store owner replied:
Thank you for the video! We are so happy you love your sproutboxes! 🌱💚 —thanks for growing with us!
Love the product. This time we added a couple more 9 in 1s and expanded their width either double or triple plus doubled a couple of others we had got last year. This has effectively doubled the capacity (we previously had six nine in ones) of the entire garden. Soil is now in place and planting has commenced.
Great experience start to finish. Sproutbox staff were so helpful helping me configure what I needed to order for my 9.5 foot x 5 foot box.
Setting up couldn’t have been easier and now I’m ready to get growing!
Thanks Sproutbox,
Jane
Store owner replied:
This is great to hear! Thank you for the 5 star review!
-Sproutbox Garden Team
My install in progress!
I bought 2 Modular 9 in 1 kits, plus 2 sets of round ends, and the extension kit so now I have:
One 8 x 2'
One 6.5 x 2'
One 5 x 2'
One 3.5 x 2'
SproutBox were marvellous in sorting out an error in shipping, customer service second to none, and very high quality planters.
Store owner replied:
Your garden looks so good! Thank you so much for sharing!
-Sproutbox Garden Team
I have 3 garden beds to replace.
I thought about going back to wood but once I started ripping out the old beds I had to give my head a shake. Carpenter ants, rot and the expense of wood stopped me from going that route.
I researched Sproutbox Garden and I have no regrets.
Great product with a modern look.
Love these boxes. Easy to assemble and move into place. Tons of info on website to help you fill them. Have 7 boxes filled with potatoes, onions, beets and lettuce.
Store owner replied:
We appreciate your kind review—thank you for choosing Sproutbox Garden beds!
-Sproutbox Garden Team
My garden bed was a cinch to put together. The extension kit has all the support rods you would need depending on the bed size you chose. Great quality and looks great too!
Store owner replied:
We love hearing this! Thanks for taking the time to leave a review.
–Sproutbox Garden Team
i love the sprout box it is high enough that the feral cats can not get in and mess up what i planted.
i have one box with plants in front of my greenhouse and they are growing very well.
There will be a 2nd box going up this week as soon as some construction happens on the house near where the new box will be. That way i can keep herbs and veg going till late fall with a cover , and it is much easier to weed than ground level. Danella Hesler
Store owner replied:
Thank you for the review! - Sproutbox Garden Team
Customer Reviews
Overall rating: 4.9 / 5 from 80 reviews.
Replacing existing beds requires extensions plus a 9-in-1 to match as close as possible the original dimensions. This is the eighth bed that I successfully rebuilt. The hardware provided allows completion usually within six inches of the old wooden structure.
Store owner replied:
Congratulations on completing your eighth bed rebuild and matching the dimensions of your original setup so closely. Enjoy your newly rebuilt garden space this growing season. -Sproutbox Garden Team
Store owner replied:
We're so pleased to hear how much you appreciate the flexibility of our 17” Tall Extension Kit and its ability to expand your planting real estate. It's wonderful to know that you found the extension process easier than expected, leading to much more planting real estate. -Sproutbox Garden Team
I am very grateful for the size exchange. Thanks to Susan, my garden looks perfect and beautiful the way I wanted it.
Store owner replied:
Thanks for the 5 stars! – The Sproutbox Garden Team
The boxes are great! Set up was easy and they are beautiful and the perfect size with the extension kits. Thank you so much for making such a great Canadian product!
Store owner replied:
We truly appreciate your feedback and support. Happy growing! – The Sproutbox Garden Team
As you can see, a work in progress! My sister and I put it together. Took a bit longer than your suggested 40 minutes - but hey, my sister is 76 years and I am 83! So we did good. And still friends!
It is perfect for me, will send more pictures as I go along.
Thank you.
Store owner replied:
It’s customers like you that make what we do so rewarding—thank you! – The Sproutbox Garden Team
A great addition to the garden bed system we already love. The modular design made it easy to customize the layout, and the extension integrated seamlessly with our existing beds. High-quality construction and a smart, flexible solution for expanding our garden this season! :)
Store owner replied:
Your review made our day—thanks for your trust and support! – The Sproutbox Garden Team
I purchased two 9 in 1's and realized that they needed to be slightly longer to fit in the space I have placed them. They were simple to add and I am very happy with how they look.
Store owner replied:
Thank you for growing with us! We’re excited to be part of your gardening journey. -Sproutbox Garden Team
I had not yet assembled my 17" 9 in 1 kit so it was very easy to add the expansion kit when I assembled the two together. I think it would be a bit difficult to add an expansion kit once the main bed is already assembled of course depending on the location. Mine are on a grass space that I dug out to allow for the slope of my property so adding an expansion kit would be quite an undertaking to change everything. Overall, though, I'm very glad that I purchased the expansion kit before the main bed was assembled.
Store owner replied:
Thank you for the review and the video, your garden is stunning!- The Sproutbox Team.
We purchased the 17" 9-in-one kit with the extension pieces. Very impressed with how easy it was to assemble, and how sturdy it is. We are using it to replace an older bed that we had built from boards, which had begun to fall apart. We're confident the Sproutbox bed will remain in good shape well into the future, and expect to replace the rest our existing beds with them over time. Thanks for the great solution!
Store owner replied:
Thank you for the great review and the video. Say hello to Lucy! We look forward to growing with you and would love to see updated photos of your Sproutbox's thriving.- The Sproutbox Team.
Love the everything I have ordered from Sproutbox. Easy assembly and look great!
Store owner replied:
Thank you for the video! We are so happy you love your sproutboxes! 🌱💚 —thanks for growing with us!
Love the product. This time we added a couple more 9 in 1s and expanded their width either double or triple plus doubled a couple of others we had got last year. This has effectively doubled the capacity (we previously had six nine in ones) of the entire garden. Soil is now in place and planting has commenced.
Great experience start to finish. Sproutbox staff were so helpful helping me configure what I needed to order for my 9.5 foot x 5 foot box.
Setting up couldn’t have been easier and now I’m ready to get growing!
Thanks Sproutbox,
Jane
Store owner replied:
This is great to hear! Thank you for the 5 star review!
-Sproutbox Garden Team
My install in progress!
I bought 2 Modular 9 in 1 kits, plus 2 sets of round ends, and the extension kit so now I have:
One 8 x 2'
One 6.5 x 2'
One 5 x 2'
One 3.5 x 2'
SproutBox were marvellous in sorting out an error in shipping, customer service second to none, and very high quality planters.
Store owner replied:
Your garden looks so good! Thank you so much for sharing!
-Sproutbox Garden Team
I have 3 garden beds to replace.
I thought about going back to wood but once I started ripping out the old beds I had to give my head a shake. Carpenter ants, rot and the expense of wood stopped me from going that route.
I researched Sproutbox Garden and I have no regrets.
Great product with a modern look.
Love these boxes. Easy to assemble and move into place. Tons of info on website to help you fill them. Have 7 boxes filled with potatoes, onions, beets and lettuce.
Store owner replied:
We appreciate your kind review—thank you for choosing Sproutbox Garden beds!
-Sproutbox Garden Team
My garden bed was a cinch to put together. The extension kit has all the support rods you would need depending on the bed size you chose. Great quality and looks great too!
Store owner replied:
We love hearing this! Thanks for taking the time to leave a review.
–Sproutbox Garden Team
i love the sprout box it is high enough that the feral cats can not get in and mess up what i planted.
i have one box with plants in front of my greenhouse and they are growing very well.
There will be a 2nd box going up this week as soon as some construction happens on the house near where the new box will be. That way i can keep herbs and veg going till late fall with a cover , and it is much easier to weed than ground level. Danella Hesler