How to Grow Potatoes in a Grow Bag

One of my potato grow bags.
Want to grow potatoes but have too limited a gardening space? Then I have a solution for you: Grow bags.

Grow Bags vs. Potato Towers

A hot topic on the Internet is potato towers. The origins of this craze seem to come from a TipNut article that claims you can grow 100 lbs. of potatoes in just 4 square feet. Sounds fantastic, doesn't it? Last fall, I was determined to make at least one potato tower, but as I did my research on them this winter, I discovered the article is...shall we say...overly optimistic about yields. I read blog and forum posts about people trying the potato towers - and ALL were disappointed. In many cases, yields were lower than if the potatoes had been grown in the ground. In NO cases were yields higher.

So I decided I should just stick with something I KNEW worked: Grow bags. Last year, in a single grow bag sitting in part-shade (not full sun, as potatoes far prefer), I harvested about 8 lbs. of edible potatoes - plus many more tiny potatoes to use for planting this year.

Grow bags are similar to towers in some respects. After all, you are growing potatoes in a container. I don't know why one works and another doesn't. I just know grow bags really do work.

Grow bags from Gardener's Supply.
I use these grow bags,which are 25 inches in diameter and 14 inches high, and are made of BPA-free polypropylene fabric that seems similar to (but not exactly like) felt. Perhaps the fabric is the key to success. It is porous enough that once the soil is well moistened, excess water flows through the fabric - and potatoes definitely don't like to sit in soggy soil. I also read somewhere (wish I could remember where) that when a potato's roots bump into the side of the bag, they branch out, creating more possibilities for potato tubers to appear. So maybe that's the key. And despite what Gardener's Supply says about the longevity of these bags, I've reused my bags for two years and they show no sign of going bad.

Choosing Potatoes for Grow Bags

I grow late-season potatoes in my grow bags, so I can vouch that they are a great choice. But I understand mid-season potatoes and fingerlings types work fine, too. So as you shop for potato seed (which is not seed, really, but a small potato with "eyes" - spots where shoots are about to grow), look for those marked mid- or late-season or "fingerling."

Plant at the time indicated on the directions that come with your seed potatoes.

How to Plant a Grow Bag with Potatoes

1. Unfold the grow bag and, for best results, place it in a location that gets full sun (at least 6 hours a day). Fill the bag with a couple of inches of good soil. (I use potting soil or general "garden soil," sold in a bag.)

2. Place potato seeds on top of the soil - at least one "eye" facing up and at least 3 inches apart.

3. Cover the potato seeds with soil, so they are at about 2 to 3 inches below the soil level. (You don't want rain to uncover the potatoes.)

4. Fold down the sides of the grow bag, creating a cuff on the outside of the bag. This allows the soil to get plenty of sun. Water well.

5. Watch the potatoes as they grow, watering just enough to keep the soil a little moist - never totally dried out. Once the stems and leaves are at least 4 inches tall, gently add more soil around them, covering the stems right up to the top cluster of leaves.

6. As the potatoes grow, keep adding soil as the potatoes grow, shortening the cuff as needed, until the grow bag is full and there is no cuff on the bag.

6. When the green leaves of the potato die back, it's time to harvest! The grow bag will probably be too heavy to just dump out, so dig around with your hands to uncover potatoes.

It's a good idea not to re-use the same soil next year, but to use fresh soil that's never grown potatoes.

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