How to Grow Potatoes in a Potato Grow Bag

 

Maika Mattson and Kevin Kuprienko

May 18, 2026

Potato grow bags are one of the easiest ways to grow potatoes at home - no raised beds, no in-ground digging, and no large garden required. All you need is a bag, the right soil mix, and a little patience. In Washington state, the best time to get started is mid-March through late April, after your last frost date. And since grow bags are portable, you can easily move them to a sheltered spot if a late frost is in the forecast.

Looking for a visual representation? Check out our video at the bottom of the page to see Kevin filling a potato grow bag next to our Growing Gardeners Club Demonstration Garden!

Not using a potato grow bag? Check out our Growing Potatoes blog post to learn how to grow potatoes in the ground or in a raised garden bed.

What you'll need

Required:

  • Potato grow bag

  • Seed potatoes

  • Potting soil

Optional:

  • Compost

  • Straw

  • Vegetable fertilizer

Step 1: Mix your soil

Start with a blend of potting soil, compost, straw, and a small amount of vegetable fertilizer. The key is keeping the mix light and airy - avoid heavy soils, which can compact over time and limit your potato growth.

Step 2: Fill the bottom of the bag

Roll the edges of your bag down and add 4–6 inches of your soil mix to the bottom. This gives your seed potatoes a light, nutrient-rich base to root into.

Step 3: Plant your seed potatoes

Place your seed potatoes on top of the soil, spacing them evenly. Cover them with a few more inches of your soil mix.

Step 4: Cover as your plants grow

Each time your potato plants grow 8 inches above the soil, cover half the growth with more of your soil mix. This encourages the plant to produce more potatoes along the buried stem - the more you mound, the better your harvest.

Step 5: Keep rolling the edges up

As you add more soil, continue rolling the edges of the bag upward. This gives you more vertical space to keep covering your plants as they grow.

Step 6: Keep mounding until the bag is full

Repeat the process throughout the growing season until the bag is full. Stay consistent with mounding and your potatoes will reward you for it.

Step 7: Harvest your potatoes

Potatoes are typically ready to harvest 10–12 weeks after planting, once the foliage turns yellow, withers, and dies back. For the largest tubers, wait until the plant is completely brown and dry. If you're after small "new potatoes," you can harvest as early as 7–8 weeks after planting, or once the plant begins to flower.

A few tips for a successful harvest:

  • Stop watering 1–2 weeks before your final harvest to toughen the skins and prevent rotting.

  • Wait a little longer after die-back. Once the leaves have completely died back, give it another 1–2 weeks before harvesting to let the skins set.

  • If your bag has a harvest flap, you can reach in early to feel for new potatoes without disturbing the rest of the plant.

  • To harvest, simply tip the bag over onto a tarp and dig through the soil to find your potatoes.

 
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