Building a Four-Square Ft. Potato Box for Maximum Harvest

Using Concrete Planter Wall Blocks

Before this project, I had never used concrete planter wall blocks (pictured) for gardening, but I had always wondered how well they work.

I was honestly impressed by how easy the build was and how sturdy the final potato box feels. As far as time, it only took two minutes after I cut my wood! If you live close to a Home Depot or similar store, you can also ask them to cut your wood for you.

Since the concrete planter wall blocks are each six inches tall, I chose to get two eight-inch wooden boards and one four-inch wooden board so that the wood overlapped in the blocks for extra sturdiness.

All the displays at Home Depot used six-inch boards, which seemed like a weaker way to stack the block. With my method, the first eight-inch board completely filled the first block but also inserted 2 inches into the next block to lock it into place.

Note that the diagram photo above finishes with a three-foot potato box, so you would need at least five planter blocks on each corner to reach a similar height. 

A key benefit of using concrete planter wall blocks to build a potato box (or any garden bed) is the ease of disassembling it for harvest and reassembling it the following year.

On the other hand, the main downside of the planter wall blocks is the higher price point. For that reason, I think they make the most sense if you use them to build a bigger raised bed to get more square footage out of them. 

I’m curious to see how well this potato bed holds up in terms of durability! If I had to build the potato bed again, I would build it all out of wood like the diagram instructs just to save some money. But the concrete planter wall blocks sure save a lot of time!

Best Soil for Growing Potatoes

Potatoes thrive in loose, well-draining, nutrient-rich soil with a slightly acidic pH. Here’s what you should aim for:

1. Soil Type

• Create a loamy or fluffy soil mix. In my case I ended up using, compost, dirt, perlite, and vermiculite.

2. Essential Nutrients

• High in Phosphorus & Potassium (for root/tuber development)
  • Add bone meal, rock phosphate, or wood ash
• Moderate Nitrogen (for leafy growth but not too much, or you’ll get excessive foliage and small tubers)
  • Use aged manure or compost for a balanced nitrogen source.
• Calcium (prevents tuber deformities and disease)

• Compost: Improves soil fertility, retains moisture, and supports beneficial microbes.
• Aged Manure: Adds nutrients gradually but should be well-aged to avoid nitrogen burn.
• Coconut Coir or Peat Moss: Helps retain moisture while keeping soil loose.

4. Drainage & Aeration

• Avoid compacting the soil—plant in hilled rows or raised beds to improve aeration.
• Loose soil structure prevents waterlogging, which can lead to rot and disease.

Why Is Bone Meal Great for Potatoes?

Bone meal is an excellent organic phosphorus source, which is essential for strong root and tuber development in potatoes. Here’s why it’s beneficial:

1. Boosts Root Growth: Phosphorus encourages deep and strong root systems, leading to larger, healthier tubers.
2. Improves Tuber Formation: Since potatoes develop underground, phosphorus plays a critical role in maximizing yield.
3. Slow-Release Nutrients: Bone meal breaks down gradually, providing long-term phosphorus availability.

Determinate vs. Indeterminate Potatoes

Potatoes can be categorized as either determinate or indeterminate, which refers to their growth habit and how they produce tubers.

• Determinate Potatoes:
  • Grow in a bushy, compact form and stop growing once they reach a certain size.
  • Produce tubers in a single layer near the soil surface.
  • Have a shorter growing season and mature earlier (typically within 70 – 90 days).
  • Best suited for container gardening or shallow planting.
  • Examples: ‘Yukon Gold,’ ‘Red Pontiac,’ ‘Kennebec.’

• Indeterminate Potatoes
  • Continue to grow taller and vine-like throughout the season.
  • Form multiple layers of tubers, meaning they benefit from “hilling” (adding soil around the base of the plant as it grows).
  • Take longer to mature (typically 90 – 120 days) but produce a higher yield.
  • Ideal for deep beds, raised beds, or grow bags.
  • Examples: ‘Russet Burbank,’ ‘German Butterball,’ ‘Purple Peruvian.’

Other Vegetables in the Nightshade Family

The Solanaceae (nightshade) family includes several common vegetables, all of which share some botanical characteristics such as being warm-season crops and often requiring staking or support. 

1. Tomatoes
   • Like indeterminate potatoes, some tomato varieties are also determinate (bushy, one harvest) or indeterminate (vining, continuous harvest).
   • Require warm weather, full sun, and support (for indeterminate varieties).
   • Contain solanine (like potatoes), though it’s mostly found in the leaves and stems.
2. Peppers
   • Includes bell peppers, chili peppers, jalapeños, and habaneros.
   • Like tomatoes, they are warm-season crops and require full sun.
   • Unlike potatoes and tomatoes, peppers do not develop tubers but are grown for their fruit.

3. Eggplant

• Requires long, warm growing seasons like tomatoes and peppers.
• Grows on a sturdy, upright plant with large leaves.
• Contains alkaloids like solanine, but in much lower quantities.

4. Tomatillos

• Related to tomatoes but grow inside papery husks (like ground cherries).
• Require similar warm-season care as tomatoes.
• Have a slightly tart flavor and are commonly used in salsas.

Best of luck if you build a potato box this year! If you enjoyed this blog post, be sure to check out my other gardening blog posts:

• Essential and Nice-to-Have Garden Products for Your Perfect Setup
• Seed Germination Tips: Improve Growth with Seed Soaking and Heat Mats
• How to Start a Garden on a Budget for Under $100
• 4 Reasons Why Tomatoes Are the Best Vegetable to Grow
• My Garden Setup: 3 Best Garden Containers for Every Gardener