grow · Grow

How to Grow Potatoes in a Bag

Growing potatoes in a bag is simple: fill a large bag halfway with compost, plant seed potatoes, and keep adding soil as shoots grow. You'll harvest fresh potatoes in about 12-16 weeks without needing garden space.

Total time: 14-16 weeks
Hands-on: 30 min
Serves: 1
Difficulty: Easy

Ingredients

1 large bag (at least 40 liters)
6 inches multipurpose compost or compost and soil mix
2-3 inches compost
3-4 seed potatoes

Step by step

Choose your bag and prepare the setup. Use a large bag that holds at least 40 liters - potato grow bags, old compost bags, or even strong garbage bags work. Roll the sides down to start with a shallow container about 8 inches deep. Make sure there are drainage holes in the bottom.
Fill with growing medium. Fill the bag with 6 inches of multipurpose compost or a mix of compost and soil. The medium should be loose and well-draining. Avoid garden soil alone as it gets too compacted in containers.
Plant the seed potatoes. Place 3-4 seed potatoes on the surface, spacing them evenly. The potatoes should have visible eyes or small shoots. Cover them with 2-3 inches more compost. Water gently until the soil feels moist but not waterlogged.
Wait for shoots to emerge. Keep the bag in a sunny spot and water when the top inch of soil feels dry. Green shoots will appear in 2-3 weeks. Once they reach 6 inches tall, you're ready for the next step.
Earth up the plants. Unroll the bag sides to make it deeper and add more compost around the shoots, leaving just the top 2 inches of green growth visible. This process is called earthing up and encourages more potatoes to form.
Continue earthing up. Repeat the earthing up process every 2-3 weeks as shoots grow taller. Keep adding compost until the bag is full or the shoots stop growing vigorously. Water regularly but never let the bag become waterlogged.
Harvest your potatoes. Small new potatoes are ready in 10-12 weeks - feel around in the soil for marble-sized tubers. For full-sized potatoes, wait until the plants flower and the foliage starts yellowing, usually 14-16 weeks. Tip the bag out to harvest all at once.

Tips & troubleshooting

Chitted seed potatoes grow faster - place them in egg boxes in a bright, cool place for 4-6 weeks before planting to encourage sprouting
Second early varieties like Charlotte or Rocket work best in bags as they produce good yields in the timeframe
Water consistently but check drainage - potatoes rot quickly in waterlogged soil, especially in containers
Place bags on bricks or wooden blocks to improve drainage and prevent roots sitting in water
Once foliage dies back completely, potatoes can stay in the bag for several weeks if kept dry

Variations

Multiple Bag System. Plant different varieties in separate bags to harvest early, mid, and late season potatoes for a continuous supply.
Hessian Sack Method. Use traditional hessian or burlap sacks for better air circulation. Roll the sides down and up just like plastic bags.
Tower Bag Growing. Start with a very deep bag and earth up more dramatically to create a tall tower. This maximizes potato yield in minimal space.

Questions

What size bag do I need for growing potatoes?: Use bags that hold at least 40 liters when full. Smaller bags restrict growth and reduce your harvest significantly.
Can I use potatoes from the grocery store?: No, grocery store potatoes are often treated to prevent sprouting. Always use certified seed potatoes from garden centers for reliable growth.
How often should I water potatoes in bags?: Check the soil daily in warm weather. Water when the top inch feels dry, usually every 2-3 days. Bags dry out much faster than ground soil.
Why aren't my potato plants producing flowers?: Some varieties flower less than others, and container-grown plants may not flower at all. Focus on the foliage health rather than flowers to judge when to harvest.
How many potatoes will one bag produce?: Expect 1-2 pounds of potatoes per bag with good growing conditions. The exact amount depends on variety, bag size, and how well you earth up the plants.