What Size Grow Bag Should I Use for Potatoes
Table of Contents
- The Importance of Grow Bag Volume
- Recommended Grow Bag Sizes for Potatoes
- Comparing Capacity and Plant Spacing
- Why Fabric Grow Bags Are Better for Potatoes
- Preparing Your Grow Bag for Planting
- Essential Care Tips for Bag-Grown Potatoes
- Harvesting Your Homegrown Bounty
- Building Your Garden with Garden Greenland
- FAQ
Growing your own food is a deeply satisfying experience, but not everyone has the luxury of a vast backyard or a dedicated garden plot. One of the most common hurdles home gardeners face is the lack of space for traditional "hilling"—the process of mounding soil around potato stems as they grow. Fortunately, grow bags offer a flexible, portable, and highly productive alternative for any patio, balcony, or driveway.
At Garden Greenland, we believe that everyone should be able to enjoy the rewards of a home harvest, regardless of their square footage. Using a fabric grow bag product is one of the most effective ways to manage soil quality and drainage for root crops. However, the success of your harvest depends largely on one critical factor: volume. Choosing the right size ensures your tubers have enough room to expand without becoming stunted or prone to rot. In this guide, we will break down exactly what size grow bag you need based on your space and your harvest goals.
The Importance of Grow Bag Volume
Potatoes are unique because they don't just grow down into the soil; they produce tubers along the underground portion of their stems. This is why gardeners "hill" or add soil as the plant grows upward. If a container is too small, the roots become cramped, the soil dries out too quickly, and the plant cannot produce a significant yield.
The depth of the bag is just as important as the width. A bag that is too shallow won't allow for enough soil layering, which is essential for maximizing the number of potatoes per plant. Conversely, a bag that is excessively large for a single plant can lead to water retention issues in the unused soil, potentially causing the seed potatoes to rot before they can even sprout.
Recommended Grow Bag Sizes for Potatoes
When selecting a bag, you will usually see sizes listed in gallons. While you can technically grow a single potato plant in a small container, most gardeners find that larger volumes provide much more consistent results and easier maintenance.
5 to 7 Gallon Bags
A 5 to 7 gallon grow bag is the absolute minimum size for potatoes. This size is best suited for "new" potatoes or early-season varieties that reach maturity quickly and don't grow quite as large.
- Capacity: 1 to 2 seed potatoes.
- Best for: Small balconies, fire escapes, or gardeners who want to test the process with minimal soil investment.
- Management: These dry out very fast in the heat of summer, so they require daily watering.
10 to 15 Gallon Bags
For most home gardeners, a 15 gallon grow bag is considered the "Goldilocks" size. It is large enough to support a healthy harvest but still light enough to move if you need to follow the sun or protect the plants from a late frost.
- Capacity: 3 to 5 seed potatoes.
- Best for: Average patios and backyard setups.
- Management: This size holds moisture much better than a 5-gallon bag while still being manageable for one person to lift when full.
20 to 30 Gallon Bags (and Larger)
If you have the space and want a significant crop of large storage potatoes, like Russets or Kennebecs, a 20 to 30 gallon bag is the way to go.
- Capacity: 6 to 8 seed potatoes.
- Best for: Large driveways or garden paths where the bags can stay in one permanent spot.
- Management: Once these are filled with soil and water, they are very heavy. We recommend placing them exactly where you want them to stay for the season before you begin filling them.
Quick Answer: For a reliable harvest, use a 15-gallon grow bag for 3–5 seed potatoes. If you have very limited space, a 7-gallon bag can support 2 plants, while a 30-gallon bag is ideal for larger crops of 7–8 plants.
Comparing Capacity and Plant Spacing
To help you plan your garden, use the table below to determine how much soil and how many seed potatoes you will need for each container size.
| Grow Bag Size | Number of Plants | Approx. Soil Volume | Best Use Case |
|---|---|---|---|
| 7 Gallon | 2 Plants | 1.0 cu. ft. | Small spaces / Early varieties |
| 10 Gallon | 3 Plants | 1.5 cu. ft. | Single person harvest |
| 15 Gallon | 4–5 Plants | 2.1 cu. ft. | Most popular / Versatile |
| 20 Gallon | 6–7 Plants | 2.6 cu. ft. | High yield / Large tubers |
| 30 Gallon | 8+ Plants | 4.0 cu. ft. | Serious storage crops |
Why Fabric Grow Bags Are Better for Potatoes
While you can use plastic buckets or even old trash cans, fabric grow bags offer distinct advantages for root vegetables. The breathable non-woven fabric allows for "air pruning." This occurs when roots reach the edge of the bag; instead of circling the container and becoming "root-bound," the tips are exposed to air and naturally stop growing, which signals the plant to produce a more fibrous and efficient root system.
Furthermore, drainage is a non-negotiable requirement for potatoes. If the soil stays soggy, the tubers will develop rot or "hollow heart." Fabric bags naturally allow excess water to seep through the walls, ensuring the soil stays moist but never waterlogged. Our collection of Grow Bags at Garden Greenland is designed with these exact needs in mind, providing the durability required to hold heavy soil and the breathability plants need to thrive.
Preparing Your Grow Bag for Planting
Once you have selected your size, the setup process is straightforward. Potatoes are heavy feeders, so the quality of your growing medium is just as important as the size of the container.
Step 1: Prepare the Soil Mix
Do not use heavy garden soil alone, as it will compact in a container and prevent tubers from expanding. Use a mix of equal parts high-quality potting soil and compost. Adding a bit of perlite or coco coir can help keep the texture light and fluffy.
Step 2: The Initial Fill
Roll down the sides of your grow bag so it is easier to reach the bottom. Fill the bag with about 4 to 6 inches of your soil mix. There is no need to fill the whole bag yet; you will add more as the plants grow.
Step 3: Planting the Seed Potatoes
Place your seed potatoes on top of the soil with the "eyes" or sprouts facing upward. Space them evenly apart, ensuring they aren't touching the fabric walls. Cover them with another 3 to 4 inches of soil and water them in well.
Step 4: The Hilling Process
As the green stems grow to be about 6 to 8 inches tall, unroll the sides of the bag slightly and add more soil mix until only the top few inches of leaves are visible. Repeat this process until the soil reaches the top of the bag. This encourages the plant to produce more potatoes along the buried stem.
For a deeper walkthrough of the hilling technique, see our guide on how to hill potatoes in grow bags.
Key Takeaway: Proper sizing prevents root-bound plants, while the "hilling" method inside the grow bag maximizes your vertical space for a much higher yield.
Essential Care Tips for Bag-Grown Potatoes
Growing in containers requires a slightly different approach than in-ground gardening. Because the bags are above ground, they are more susceptible to temperature fluctuations and drying out.
- Sunlight: Potatoes need at least 6 to 8 hours of direct sunlight. If your patio is shaded in the morning, use the handles on your grow bags to move them into the afternoon sun.
- Watering: Check the soil daily by sticking your finger an inch deep. If it feels dry, water until you see moisture seeping from the bottom of the bag. During the height of summer, you may need to water twice a day. If you want an automated option, browse our Watering & Irrigation collection for drip kits and timers that help maintain consistent moisture.
- Fertilizing: Since frequent watering can wash away nutrients, we recommend using a balanced, water-soluble fertilizer every two weeks once the plants are established.
- Pest Control: Keep an eye out for the Colorado potato beetle. Inspect the undersides of leaves regularly and remove any bright orange egg clusters or larvae by hand. Using products from our Pest Control collection early can prevent a small infestation from ruining your crop.
For troubleshooting yellowing foliage or checking depth recommendations, see our post on how deep to plant potatoes in a grow bag.
Harvesting Your Homegrown Bounty
The most exciting part of using grow bags is the harvest. You don't need a heavy garden shovel product or a fork that might accidentally spear your potatoes. When the foliage turns yellow and begins to die back—usually 90 to 120 days after planting—the potatoes are ready.
To harvest, simply spread a tarp on the ground and tip the bag over. You can sift through the loose soil with your hands to find every last tuber. This "dump and discover" method is much cleaner and more thorough than digging in the ground. Once harvested, let the potatoes sit in a cool, dark place for a few days to "cure," which allows the skins to toughen up for longer storage.
Note: Never wash potatoes you intend to store. Simply brush off the dry soil. Moisture on the skin can lead to mold and spoilage in storage.
If you want tips on maximizing yield per bag, check our article about how many potatoes to plant in a grow bag for optimal yields.
Building Your Garden with Garden Greenland
Choosing the right size grow bag is the first step toward a successful potato season. Whether you are starting with a single 7-gallon bag on a small balcony or lining your driveway with 30-gallon containers, we have the equipment to help you succeed. From durable Grow Bags and nutrient-rich Garden Pots & Planters to efficient Watering & Irrigation kits, we provide everything a home gardener needs to cultivate a productive green space.
If you need tools for planting and harvest, explore our Garden Tools collection and protective Garden Gloves to make the season easier.
At Garden Greenland, we believe everyone deserves to connect with nature and enjoy the rewards of growing their own food. Our goal is to make that journey as simple and successful as possible with practical tools and reliable advice.
What to do next:
- Measure your available sunny space to see how many bags will fit.
- Select a potato variety (Early, Mid, or Late season) based on your local climate.
- Prepare your soil and compost mix in advance of the spring planting window.
- Order your grow bags early so you are ready to plant as soon as the last frost passes.
FAQ
Can I reuse my grow bags for potatoes next year?
Yes, fabric grow bags are very durable and can typically be reused for 3 to 5 seasons. After harvesting, empty the soil, let the bag dry, and brush out any remaining debris before storing it in a dry place for the winter. For storage-friendly options, see our Grow Bags collection.
How many seed potatoes go in a 10-gallon bag?
In a 10-gallon bag, you should plant approximately 3 seed potatoes. This provides enough room for the tubers to grow to a good size without the plants competing too heavily for nutrients and water. For planning tips, read our post on how many seed potatoes per 10 gallon grow bag.
Why are the leaves on my potato plant turning yellow?
If the leaves turn yellow late in the season, it is a natural sign that the plant is reaching maturity and the potatoes are ready for harvest. If it happens early in the season, it may indicate a nitrogen deficiency or overwatering, so check your moisture levels and feeding schedule. Our article on common potato problems and fixes can help diagnose issues.
Do I need to poke holes in my grow bag for drainage?
No, high-quality fabric grow bags are made of a breathable material that allows water to drain naturally through the entire surface. This prevents the "wet feet" that can lead to rot in traditional plastic containers or buckets. For more on drainage and air pruning, see do grow bags need drainage holes?
