Growing Potatoes in Bags: Tips for Success - Plant Care Guide

Growing potatoes in bags is an excellent method for gardeners with limited space, poor soil, or those seeking an easier harvest. Success hinges on selecting the right bag, preparing proper soil, and consistently "hilling up" the growing plants.

Why Grow Potatoes in Bags?

Growing potatoes in bags offers several distinct advantages over traditional in-ground planting, making it a popular choice for urban gardeners, those with small yards, or anyone looking for a less labor-intensive approach.

Space-Saving Solution

One of the primary benefits is the efficient use of space.

• Small Spaces: Perfect for balconies, patios, rooftops, or any small outdoor area where a traditional garden bed isn't feasible.
• Portability: Bags can be moved to follow the sun or protect plants from extreme weather, which isn't possible with in-ground planting. This flexibility makes potato bags ideal.
• Vertical Growth: The hilling process allows potatoes to grow upwards, maximizing yield in a smaller footprint.

Easier Harvest

The harvest process is significantly simplified when growing potatoes in bags.

• No Digging: Instead of laborious digging, you simply tip the bag over, and your potatoes spill out. This reduces effort and minimizes the risk of piercing tubers.
• Cleaner Potatoes: Potatoes harvested from bags tend to be much cleaner, as they are grown in controlled, often soil-free, potting mixes.
• Less Damage: Less chance of leaving potatoes behind or damaging them with a spade.

Pest and Disease Control

Container growing can help mitigate some common potato problems.

• Reduced Soil-Borne Pests: Using fresh, sterile potting mix can limit exposure to soil-borne pests like wireworms or diseases like scab.
• Easier Scouting: Pests on foliage are often easier to spot and manage when plants are contained.
• Crop Rotation: Bags allow you to easily rotate where your potatoes are grown each year, which is crucial for preventing disease buildup in the soil.

Soil Quality Control

You have complete control over the growing medium.

• Poor Soil: If your native garden soil is heavy clay, rocky, or has poor drainage, potato grow bags bypass these issues entirely.
• Custom Mix: You can create the ideal, loose, well-draining, and nutrient-rich environment that potatoes love.

Table: Pros and Cons of Growing Potatoes in Bags

What Type of Bag is Best for Growing Potatoes?

Choosing the right potato grow bag is crucial for ensuring proper drainage, aeration, and ultimately, a successful harvest.

Fabric Grow Bags: The Top Choice

Fabric grow bags, often made from non-woven polypropylene fabric, are by far the most recommended type for growing potatoes.

• Excellent Drainage: The breathable fabric allows excess water to drain away freely, preventing soggy soil and root rot, which potatoes are very susceptible to.
• Superior Aeration: The fabric allows air to penetrate the soil from all sides, promoting healthy root growth and preventing heat buildup, especially in warm climates. This "air pruning" helps create a denser, more fibrous root system.
• Durability: High-quality fabric grow bags are durable and can last for several seasons. Many come with reinforced handles for easy movement.
• Material: Look for thick, heavy-duty fabric grow bags designed specifically for potatoes or vegetables. A 7-10 Gallon Fabric Grow Bag is a good size for most varieties.
• Window Option: Some fabric bags come with a handy Velcro or flap "harvest window" at the bottom, allowing you to check for or even harvest mature potatoes without disturbing the entire plant.

Other Bag Options (with caveats)

While fabric bags are ideal, other containers can be adapted.

• Burlap Sacks: These are breathable and drain well, but they break down quickly and may not last an entire growing season. They are often a one-time use option.
• Plastic Nursery Pots/Buckets: If using plastic, they must have plenty of drainage holes drilled into the bottom. Their lack of breathability can lead to overheating and root issues in hot weather, and they don't offer the air-pruning benefits of fabric. Use light-colored plastic to reflect heat.
• Heavy-Duty Reusable Shopping Bags: Similar to plastic pots, these would require significant drainage holes. Material quality varies widely.

Recommended Bag Sizes for Potatoes

The size of the bag influences the potential yield per plant.

• Minimum Size: A 7-gallon (approx. 26.5 liters) bag is generally the minimum recommended size for one potato plant.
• Optimal Size: A 10-gallon (approx. 38 liters) bag is often preferred, providing more space for tuber development and a potentially larger yield. You can usually plant 1-2 seed potatoes in a 10-gallon bag.
• Larger Bags: While larger bags (e.g., 15-20 gallons or more) can hold more plants, they become very heavy when filled with soil and wet. For ease of management, it's often better to use multiple 10-gallon bags.

Table: Bag Type Comparison for Potatoes

What Soil Mix is Best for Growing Potatoes in Bags?

The right soil mix is paramount for growing potatoes in bags, as it provides the sole source of nutrients, moisture, and support for your plants. Potatoes thrive in a loose, well-draining, and slightly acidic medium.

Ideal Characteristics of Potato Bag Soil

Aim for a mix that offers these qualities:

• Light and Fluffy: Potatoes need loose soil to expand easily. Dense, heavy soil can restrict tuber development, leading to smaller or malformed potatoes.
• Well-Draining: Crucial to prevent waterlogging, which can cause root rot and fungal diseases. Fabric bags help with drainage, but the soil mix must also facilitate it.
• Moisture-Retentive: While well-draining, the mix should still hold enough moisture to keep the potatoes hydrated without staying soggy.
• Nutrient-Rich: Potatoes are moderate to heavy feeders. The soil needs to provide consistent nutrients throughout their long growing season.
• Slightly Acidic pH: Potatoes prefer a slightly acidic soil pH, ideally between 5.0 and 6.0. This helps prevent potato scab, a common disease that causes unsightly lesions on tubers.

Components of a Good Potato Potting Mix

A successful potato growing mix is usually a blend of several components.

1. Potting Mix (Base): Start with a high-quality all-purpose potting mix as your base. Avoid heavy garden soil, which can compact too much in containers and introduce diseases. Look for a peat-based or coir-based mix. A Organic Potting Mix is a great foundation.
2. Compost: Incorporate a generous amount of well-rotted compost (1/4 to 1/3 of the total mix). Compost enriches the soil with nutrients, improves drainage, and enhances moisture retention. It's vital for healthy potato plant growth.
3. Perlite or Vermiculite: Add 1 part perlite or vermiculite to 3-4 parts potting mix/compost blend. These lightweight materials improve drainage and aeration. Perlite is better for drainage, while vermiculite has more moisture-retention properties.
4. Aged Manure (Optional): If available, a small amount of well-aged manure (e.g., cow, chicken, horse) can provide a slow-release source of nutrients. Ensure it is fully composted to avoid burning plants.
5. Bone Meal or Rock Phosphate (Optional): For an extra boost of phosphorus, which is essential for root and tuber development, you can add a handful of bone meal or rock phosphate to the mix.

Mixing Your Own Soil for Potato Bags

Follow these steps to create your ideal potato bag soil mix.

1. Gather Ingredients: Collect your chosen potting mix, compost, perlite/vermiculite, and any optional amendments.
2. Mix Thoroughly: In a large wheelbarrow or on a tarp, thoroughly mix all the components together. Ensure an even distribution of materials.
3. Moisten Slightly: Slightly moisten the mix before filling the bags. It should be damp but not soggy – like a wrung-out sponge. This prevents dusty conditions and helps the soil settle.

Example Soil Mix Ratio:

• 2 parts high-quality potting mix
• 1 part well-rotted compost
• 1/2 part perlite

How Do You Plant Seed Potatoes in Bags?

Planting seed potatoes in bags is a straightforward process, but preparing your seed potatoes and correctly layering the soil are crucial steps for maximizing your yield.

Chitting Seed Potatoes: Get a Head Start

"Chitting" is the process of pre-sprouting your seed potatoes before planting. This gives them a head start and can lead to an earlier and potentially larger harvest.

1. Select Healthy Seed Potatoes: Always use certified disease-free seed potatoes purchased from a garden supplier. Do not use grocery store potatoes, as they may be treated with sprout inhibitors and can carry diseases. A Variety Pack of Seed Potatoes offers diverse options.
2. Cut if Large: If your seed potatoes are larger than a chicken egg, cut them into pieces. Each piece should have at least 1-2 "eyes" (small indentations where sprouts emerge) and be about 1.5-2 ounces (40-55 grams) in size.
3. Callus Over: Allow the cut pieces to air dry for 1-2 days in a cool, well-ventilated spot. This forms a protective layer (callus) over the cut surface, preventing rot once planted.
4. Lay Out: Place whole or cut seed potatoes in a single layer in an egg carton or shallow tray, eyes facing upwards.
5. Provide Light: Place the tray in a cool (around 50-60°F or 10-15°C), bright spot with indirect light. Avoid direct sunlight, which can scorch them.
6. Wait for Sprouts: In 2-4 weeks, strong, stubby, greenish-purple sprouts will emerge. These are ideal for planting. Avoid thin, white sprouts that form in the dark, as they are weak.

Step-by-Step Bag Planting

Once your seed potatoes are chitted, you're ready to plant!

1. Prepare the Bag: Unfold your grow bag and roll down the sides to create a short "collar" about 6-8 inches (15-20 cm) high. This allows for easier initial planting and later hilling.
2. Add Initial Soil Layer: Fill the bottom of the bag with about 4-6 inches (10-15 cm) of your prepared potato soil mix.
3. Place Seed Potatoes:
   • For a 7-gallon bag: Place 1 seed potato in the center.
   • For a 10-gallon bag: Place 1-2 seed potatoes, spaced evenly.
   • For larger bags: Space potatoes about 8-12 inches (20-30 cm) apart.
   • Ensure the eyes/sprouts are facing upwards.
4. Cover with Soil: Cover the seed potatoes with another 4-6 inches (10-15 cm) of soil mix.
5. Water In: Water thoroughly to settle the soil around the seed potatoes.
6. Locate Bag: Place the bag in a spot that receives at least 6-8 hours of full direct sunlight daily.

Table: Seed Potato Preparation and Planting

How Do You "Hill Up" Potatoes in Grow Bags?

Hilling up is the most critical technique for growing potatoes in bags. This process encourages the plant to produce more tubers along the stem, increasing your yield.

The Purpose of Hilling

• Encourages Tuber Formation: New potatoes (tubers) form along the stem that is buried under the soil. Hilling provides more stem length for these tubers to develop.
• Protects from Sun: Hilling keeps the developing tubers buried, preventing them from being exposed to sunlight. Sun exposure turns potatoes green and makes them bitter and potentially toxic (solanine).
• Supports the Plant: As the plant grows taller, the added soil provides stability.

Step-by-Step Hilling Process

Hilling is done in stages as your potato plants grow.

1. First Hilling (1st Hilling):
   • When: When the potato plant sprouts reach about 6-8 inches (15-20 cm) tall.
   • How: Gently unroll the sides of the grow bag another 4-6 inches (10-15 cm). Add more potato soil mix around the plant, covering all but the top 3-4 inches (7.5-10 cm) of foliage. This means burying about 3-4 inches of the stem.
2. Subsequent Hillings (2nd, 3rd Hilling, etc.):
   • When: Repeat the hilling process every time the plant grows another 6-8 inches (15-20 cm) tall.
   • How: Continue unrolling the bag and adding soil, always leaving the top 3-4 inches of foliage exposed.
3. Final Hilling: Continue until the bag is nearly full of soil, typically leaving about 1 inch (2.5 cm) from the top rim. At this point, the potato plant should be a substantial leafy bush.

• Frequency: You'll likely need to hill up 2-4 times throughout the growing season, depending on the potato variety's growth rate.
• Material: Always use your well-draining, loose potato soil mix for hilling. Do not use heavy garden soil.

Example Hilling Schedule:

What Care Do Potatoes in Bags Need?

Consistent care, especially regarding watering and feeding, is vital for a bountiful harvest of potatoes grown in bags.

Watering: The Most Critical Factor

Container-grown potatoes dry out much faster than in-ground potatoes.

• Consistent Moisture: Potatoes need consistent moisture, especially once they start forming tubers (after flowering). Irregular watering can lead to malformed or cracked potatoes.
• Deep Watering: Water thoroughly until you see water draining from the bottom of the bag.
• Frequency: In hot, sunny weather, you may need to water daily, sometimes even twice a day. In cooler weather, every 2-3 days might suffice. Always check the soil moisture by sticking your finger about 2 inches (5 cm) deep. If it feels dry, it's time to water.
• Avoid Overhead Watering: While fabric bags dry out quickly, aim to water the soil directly to keep foliage dry, which helps prevent fungal diseases.

Fertilizing: Fueling Tuber Growth

Potatoes are heavy feeders and will benefit from regular fertilization.

• Initial Boost: Your prepared soil mix with compost provides initial nutrients.
• Mid-Season Feeding: Once the plants are established and have been hilled a couple of times (around 4-6 weeks after planting), begin fertilizing.
• Low Nitrogen, High Phosphorus/Potassium: For tubers, you want a fertilizer that is lower in nitrogen (N) and higher in phosphorus (P) and potassium (K). An NPK ratio like 5-10-10 or 6-24-24 is ideal. Too much nitrogen will promote leafy growth at the expense of tubers.
• Application: Use a granular potato fertilizer incorporated into the top layer of soil during a hilling, or a liquid feed applied with watering every 2-3 weeks. A Organic Potato Fertilizer can provide balanced nutrients.
• Cease Fertilizing: Stop fertilizing once the potato plants begin to yellow and die back, as they are nearing harvest.

Sunlight: Maximize Exposure

• Full Sun: Potatoes need at least 6-8 hours of full direct sunlight daily for optimal tuber development.
• Adjust Position: If your bags are portable, move them throughout the day to maximize sun exposure.

Pest and Disease Management: Vigilance is Key

Even in bags, potatoes can attract pests and diseases.

• Common Pests: Watch out for Colorado potato beetles (adults and larvae can defoliate plants) and aphids (tiny insects that cluster on new growth).
• Diseases: Early blight and late blight are common fungal diseases. Good air circulation and keeping foliage dry are preventative.
• Inspection: Inspect your plants regularly. Remove any diseased leaves or pest infestations promptly.
• Organic Solutions: For pests, hand-picking, a strong spray of water, or neem oil can be effective. For fungal issues, ensuring good airflow and proper watering are crucial. A Neem Oil Insecticide is a versatile organic option.

When and How Do You Harvest Potatoes from Bags?

The moment you've been waiting for! Harvesting potatoes from bags is incredibly satisfying and one of the biggest advantages of this growing method.

Signs of Maturity: When to Harvest

• Flowering (Optional Indicator): Many potato varieties will flower. This indicates that tubers are starting to form, but it doesn't mean they're ready for harvest.
• Yellowing and Dieback of Foliage: The primary sign that your potatoes are ready to harvest is when the plant's foliage begins to yellow, wither, and eventually die back. This typically happens 90-120 days after planting, depending on the variety (early, mid-season, late).
• Wait for Dieback: It's important to wait until the tops have fully died back or have been killed by a light frost. This allows the potato skins to "set" or thicken, which improves their storage life. If you harvest too early, the skins will be thin and easily damaged.

Harvesting New Potatoes (Optional)

You can harvest "new potatoes" earlier in the season if your bag has a harvest window.

• Timing: About 60-70 days after planting, when the plant is actively growing and flowering.
• Method: If your bag has a window, gently open it and carefully feel around in the soil for small, young tubers. Take a few, then close the window and re-cover the roots with soil. The plant will continue to grow. This method works well with fabric bags that have a side flap.

The Main Harvest: Tipping the Bag

For the full harvest, follow these simple steps.

1. Stop Watering: About 1-2 weeks before your anticipated harvest, stop watering the bag. This helps cure the potato skins and makes them easier to handle.
2. Prepare a Tarp or Area: Lay down a tarp or designate a clean area where you can empty the bag.
3. Tip the Bag: Simply tip the grow bag over onto the tarp. The soil and potatoes will spill out.
4. Collect Potatoes: Gently sift through the soil to collect all the tubers. Be careful not to bruise or cut them. You'll be surprised how many potatoes can come out of one bag!
5. Cull Damaged Potatoes: Set aside any potatoes that are green, cut, bruised, or diseased. These should be consumed quickly or discarded, as they won't store well.

Curing and Storing Your Harvest

Proper curing ensures your potatoes last longer.

• Curing: After harvest, gently brush off excess soil (do not wash them). Lay the potatoes in a single layer in a cool (50-60°F or 10-15°C), dark, well-ventilated area for 1-2 weeks. This process allows the skins to toughen and any minor injuries to heal.
• Storage: After curing, store your potatoes in a cool, dark, well-ventilated place (like a root cellar, cool pantry, or basement). Avoid storing them in plastic bags, as this traps moisture and encourages rot. Use mesh bags or breathable containers. Keep them away from apples, as the ethylene gas from apples can cause potatoes to sprout prematurely.

Table: Potato Harvest and Storage Stages

By following these tips, growing potatoes in bags can be a highly rewarding and efficient way to enjoy fresh, homegrown potatoes, even in the smallest of spaces.