I’ve been growing potatoes in the ground for years and this has always resulted in an edible crop. Whether the potatoes were small or large, depended on the quality of the soil.
In heavy soils such as clay, I would end up with smaller potatoes but in more sandy soils, the potatoes would be larger as it was easier for them to grow in the soil.
What I didn’t like about growing potatoes in the ground was the fact that once you’ve grown potatoes in a certain spot in the garden, you would always end up with a crop the next season whether you wanted them to grow there or not.
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So, a couple of years ago, I decided to give potato grow bags a try. While the results were not what I expected, I did end up with a decent crop.
My Expectations Of Using Potato Grow Bags
I’m sure you’ve all seen those lovely photos on Pinterest where when you open the velcro flap of the potato bag, potatoes just come tumbling out. And, that’s kind of what I was expecting.
So, as I gently opened one access flap, you can imagine my disappointment when there were no visible new potatoes even though the plants had been growing really well.
I opened the other flaps and still no visible potatoes.
Then, I had a dig around in the soil in the bag and finally, I found quite a few lovely potatoes.
So, what had I done wrong? I thought about it for a while, and then the answer hit me. I can’t believe I hadn’t realised this at the outset. But, as I always say, gardening is an adventure and we’re all amateur scientists.
Why Were My Expectations Not Met?
To understand why I didn’t get the results I was expecting, I had to think about how potato tubers grow. You see, the tubers grow very close to the base of the plant.
Potato plants don’t generally send down long roots from which the tubers then grow. If you’ve ever grown potatoes in your garden and then dug up the plant, you would have noticed that all the tubers were close to the base of the stem.
So, what I discovered was that I just hadn’t planted the seed potatoes deep enough into the grow bag to then have new tubers tumbling out of the flaps.
Another thing that I realised was that if you buried more of the stem in the soil, more tubers would grow from the stem that was buried in the soil.
That’s when I had that aha moment and realised how growing potatoes in gallon potato grow bags could be really beneficial and produce quite a decent crop if you do it right.
So, here’s my guide to growing a bumper crop of potatoes using grow bags.
Select Bags That Are Porous Or Have Good Drainage Holes
Before you follow my instructions, make sure that you purchase high quality grow bags. This means that you’ll be able to use them over and over again. The size of the grow bag will determine how many tubers you’ll be able to grow in each one.
If the bag is too small, you might end up with a smaller harvest or lots of small potatoes.
Don’t Fill The Bag With Soil
When you get your brand new potato planter bag either online or from garden centers nearby, don’t get overenthusiastic and fill the entire bag with soil.
You only want to add around 7.5 cm (3 inches) of soil mixed with organic matter into the bottom of the bag. You can roll down the sides of the bag to make it easier to get to the bottom of the bag.
By the way, you can even use jute sacks to grow your potatoes. Just make sure that they have good drainage so the excess water can drain away freely.
Once you have a layer of soil in the bag, plant your seed potatoes into this. Remember, you don’t grow from potato seeds but rather, the tubers themselves.
You don’t have to plant them very deep as you only have a shallow amount of soil to work with. By the way, this method will also work if you’re growing potatoes in a raised bed.
Add More Soil As The Plant Starts To Grow
As you notice the tubers sprouting and you have some green growth above the soil, you want to add some more soil to partially cover the emerging stems of the plants. Don’t cover the green sprouts totally because the plants do need sunlight to grow.
Essentially, you want to bury around half the emerging stem in the soil. So, if your plant has grown to 15 cm (6 inches) high, add more soil to cover around 7.5 cm (3 inches) of the exposed stem. You can even go as far as adding enough soil so that only the tips of the plants are showing.
Make sure you keep the plants well-watered at the same time. Potato grow bags are naturally self-draining so your plants won’t have to deal with wet feet.
Continue to add more soil as the stems grow ever upward. You can start to roll up the sides of the bag as you do this in order to contain the soil
Keep Adding Soil Until You Reach The Top Of The Bag
Over the next few weeks, continue to add more soil into the bag, covering around half the stem each time. You can stop once you reach the top of the bag. You can add a layer of mulch on top of the soil to help conserve moisture.
If you do this, you should end up with new tubers growing not only at the bottom of the bag but also right throughout the entire contents of the bag.
And, if you want a bag full of potatoes, make sure you plant multiple seed potatoes in the same bag. You can even mix up the varieties and have a mixture of different potatoes all growing in the same bag.
Growing potatoes in these bags also means that you can use the bags for other plants after the potatoes have finished. All you have to do is tip the soil from the bag into a wheelbarrow or garden cart and rake through it thoroughly to remove any tiny tubers that you may have missed while harvesting your crop.
You can reuse the same soil but I would mix it with about the same volume of new, fresh mix or compost in order to freshen it up. If you do this, you’re going to have enough soil for two bags instead of one!
Frequently Asked Questions
At a minimum, I would plant around 6 seed potatoes in a grow bag to get a decent crop of new tubers.
Currently, I’m using bags that are 40 cm (16 inches) in diameter and 55 cm (22 inches) high.
It’s a good idea to purchase good quality seed potatoes as these will produce the best results. However, if you have some store-bought tubers that have sprouted, you can try growing these as well.
The best time to plant your potatoes into grow bags is late winter or early spring when any danger of frost has passed. Their main growing season is over summer.
This will depend on whether you receive any rain or not. If the weather is dry, water your grow bags at least once a week and ensure you give the soil a good soaking.
Whether growing in bags or pots, you should always use a premium potting mix as this is the right consistency and also contains nutrients. If you have your own compost, you can mix this with the potting mix in a 50:50 ratio. Avoid using garden soil because this is too heavy and will become compacted very quickly.
As I’ve already explained, you need to plant your potatoes really deep in the bag or in the bottom 7.5 cm (3 inches) of the soil.
Ideally, you want to position your potato planting bag in a sunny spot. But, I’ve grown potatoes successfully when they receive morning sun and afternoon shade.
If you’re using premium potting and compost mix, you shouldn’t have to supply your plants with any additional fertiliser. However, if you’re reusing potting mix, add some organic fertiliser pellets to the mix before putting this into your grow bags.
It’s perfectly fine to reuse your grow bags the following year for growing potatoes as long as you refresh the potting mix as I’ve outlined above. This means that you don’t have to buy a new bag at the beginning of the season.
Generally, it will take around 3 months or 120 days before you can harvest your potatoes. In saying that, you might be able to harvest some smaller tubers before this.
This is not necessary because once the potato leaves die back, it means that the tubers are ready to harvest. When this happens, it’s just a case of tipping out the bag, discarding the foliage, and harvesting all the tubers.
Final Thoughts
Growing potatoes in bags is easy when you know how and a great option for home gardeners with small spaces and those who don’t want their veggie beds overrun by potatoes.
Homegrown potatoes have so much more flavor than those that you can buy from the grocery store and you’ll love the fact that you’ve been able to grow your own food. If you follow my advice, at harvest time, you’ll be rewarded with loads of potatoes that you can enjoy.
