I've been growing potatoes in grow bags since 2011. Why would I do that when I have plenty of space to plant them in the ground? Because I find grow bags produce bigger harvests. It's true!

I've often wondered why this is; I don't have a definitive answer, but some folks claim it's due to the felt-like material most grow bags are made of. When the roots of the potatoes touch the sides of the bag, they say, those roots branch out more than usual, which in turn creates more potatoes.

There are other good reasons to grow potatoes in grow bags, too. They are an excellent choice if you don't have a lot of space for rows of potatoes, for example, or if you have lousy garden soil.

What Type of Potatoes to Put in Grow Bags

Late-season varieties do especially well in grow bags.

I typically only grow mid- to late-season potatoes (usually Kennebec, but this year I couldn't find that variety, so I went with Yukon Gold); I can certainly vouch that they do well in grow bags. That said, you can really grow any type of Irish potato in a grow bag.

Do, however, make the effort to buy seed potatoes. These are not really seeds, but are small potatoes grown just for the purpose of making new plants. Store bought potatoes (even if organic) are sprayed with inhibitors that help prevent potatoes from growing green shoots as quickly as they naturally would. In addition, store bought potatoes (or even potatoes you've grown yourself) were not grown specifically to make vibrant "seed." They may also harbor disease, even if the mother plant showed no sign of disease. By spending just a bit on seed potatoes, you ensure a healthier, more robust harvest.

If your seed potatoes don't yet have "eyes" (i.e., little sprouts coming up out of them), you should encourage them to grow by leaving the seed potatoes in a cool spot with natural sunlight for approximately 1 month to 8 weeks before planting. However, while this practice (called "chitting") is widely recommended, and while there is some evidence that chitting makes potatoes grow faster (according to Plant Your Patch, chitting results in 20% more yield from plants), if you neglect to chit your potatoes, it isn't the end of the world. 

Seed potato with an "eye."

What you really do need to do, though, it cut up any seed potatoes that are bigger than a chicken's egg. About 2 days before planting, simply take a knife and cut the seed potatoes into approximately egg-sized pieces, being sure each piece has at least one eye (preferably two). Let these sit for a couple of days so they can develop a "skin" over the cut parts, which helps reduce the risk of rot once you plant the seed potatoes.

When to Plant Potatoes

When it comes to planting times, it's wise to consult the packaging your potatoes came in. It should contain either a chart or a graphic showing your country divided into different growing zones. From this, find your zone and the planting dates suggested for your area and the type of potatoes you are growing.

In general, though, you should plant potatoes after your last threat of frost has passed and when the soil temperature is 55 degrees F. during the day. If the soil is very wet, put off planting potatoes until it's dried out a bit.

Where to Plant Potatoes

Well, duh! Plant them in grow bags, right? Yes, yes...but where should you put these grow bags? Potatoes prefer sunny locations, so look for a spot with at least 6 hours of sunlight a day. In the past, I've grown potatoes in part shade - it is do-able, but your yields will be smaller.

How to Plant Potatoes in Grow Bags

Potatoes prefer nutrient-rich, slightly acidic (pH 5.8 to 6.5) soil, but they also aren't very fussy. They'll grow in most soil types - just make sure whatever you use is well-draining. So if your garden soil is heavy clay, you're better off using potting soil in your grow bag.

1. To begin, put about 1 inch of manure (mine is rabbit manure, filled with worms, since it's been sitting in a pile in my garden area for a while) in the bottom of each grow bag. If you don't have manure that's ready for gardening (most types must be aged), you could put compost in the bottom of the bags instead. (You could also mix manure or compost in with your garden soil before filling the bags.)

Adding manure or compost.

2. Now add about 4 inches of soil to the bag.

3. Next, plant the seed potatoes. Perhaps counterintuitively, potatoes grown in grow bags produce higher yields if you crowd them a bit, so plant 7 or 8 in a 30-gallon bag. Dig down a couple of inches, and place the potatoes eye-side up.

Place potato seeds eye side up.

Crowd your potato seeds a bit.

4. Cover the potatoes with more soil, so they are about 3 or 4 inches under the dirt.

5. Fold down the sides of the grow bag (creating a cuff), until it's just a couple of inches above the soil. This allows the plants, once they sprout, to get more sun.

6. If you're not expecting rain, water well.

How to Care for Potatoes in Grow Bags

Once the potato leaves are about 8 inches tall, add more soil to the grow bag. It's fine if some of the leaves get buried in the soil. Unfold the cuff of the grow bag as needed to accommodate the additional soil.

Repeat this step as often as necessary throughout the growing season.

tr-caption" style="text-align: center;">Potatoes sprouting in a grow bag.

Potatoes in grow bags (or any type of container) dry out more quickly than if they're grown in the ground, so pay careful attention to irrigation. If you can stick your finger 1 inch down into the soil and it feels dry, you need to water. On the other hand, you don't want your potatoes sitting in a soggy grow bag. Aim to keep the moisture level in the bag even throughout the growing season

How to Harvest Potatoes Grown in a Grow Bag

Thriving grow bag potatoes. Soon the tops will yellow and wilt, a sign that harvest time is near.

As the potato plant nears harvesting season (which varies, depending on the type of potatoes you're growing), the leaves will yellow and the stems will wilt. When this happens, stop watering. Wait a week or two.

Now, at last, you can harvest your potatoes. I do this by carefully digging around the grow bag with my hands; a hand held spade works, too, but if you want to store your potatoes, don't nick or puncture them. If you're stronger than I am, you can also dump the contents of the grow bag into a wheelbarrow and pull out the potatoes you find.

Brush the dirt off the potatoes with your hands; do not wash them until you're ready to cook them. Put the potatoes in a single layer in a cool room, covered with a bed sheet to help block sunlight. This allows the potatoes to "cure," letting the skins dry out. Potatoes with thin skins (like fingerlings) cure quickly; those with thick skins (like Russets) take longer. Generally, potatoes cure in 7 to 10 days.

Store the cured potatoes in a cool, dark location, ideally with a temperature of about 45 to 55 degrees F. Cardboard boxes are great for storing potatoes; baskets, with their potentially pokey edges that can damage the crop, are not. If you've grown several types of potatoes, it's smart to sort out the ones with thinner skins, so they can be eaten first; thin-skinned potatoes don't last very long in storage.

Reuse!

The soil you've used for growing your potatoes can be re-used for non-nightshade plants. (Using the same soil for more potatoes or for any plant in the potato family - which includes tomatoes, peppers, and eggplant - means the soil won't have all the nutrients needed...and it's more likely to harbor diseases that will maim or kill those plants.) It's smart to add compost or other organic matter before re-using the soil, however. Another option is to dump the used soil in your compost bin or use it as dust bathing material for your chickens or quail.

The grow bags can be used again next year. I've had my original grow bags for 12 years, and they are still working great! This year, I wanted to add to my arsenal of bags, but couldn't find the exact ones I purchased years ago, so I bought these. So far, they seem quite comparable to my original bags.

Other Ways to Plant Potatoes

If this method doesn't trickle your fancy, there are plenty of other ways to plant potatoes! Check out this post for all the best methods.

Cover image courtesy of Conall. A version of this article first appeared in July 2013.