Growing Potatoes in Your Garden

Growing potatoes in allotments and gardens is popular. Indeed, along with tomatoes, potatoes are probably one of the first grow your own crops that people experiment with. Perhaps it’s appropriate then that both potatoes and tomatoes originate from the Americas and are members of the same family – Solanum.

Wild potatoes can still be found growing from the southern states of the USA down to Chile in South America. And they were one of the earliest crops domesticated in South America, around 7000 years ago.

Why Grow Potatoes?

With many people having limited space for growing their own fruit and vegetables, you may wonder if it’s worthwhile growing potatoes in your garden. Generally speaking, potatoes are not expensive to buy. Until you want early potatoes or organically grown potatoes or a heritage variety that is!

It makes sense then, if you have limited space, or limited time, to choose a variety of potato that your family likes to eat and which is more difficult to find in the shops and farmers market or is more expensive to purchase.

Those called ‘new’ or ‘baby’ are actually early potatoes, and there are first early and second early types. The main difference between these and maincrop potatoes is the length of time they’re in the ground (see below). If you’re short on space then early potatoes are a better option to grow.

What are Seed potatoes?

Seed potatoes are not seeds such as you would buy in a seed packet. Potatoes are grown vegetatively, which means the seed potato is a piece of potato rather than a seed from a pollinated flower.

Because of this method of propagation, any diseases that were in the potato crop the previous year will be carried within the seed potato. Which is why it is very important to use certified disease free seed potatoes and not leftovers from your weekly supermarket shop.

However, these seed potatoes should be freshly bought each year, as once they are in the ground they may contract soil-borne diseases which would be carried over to subsequent year.

Preferably, you should get your seed potato order in early (November / December prior to planting) to ensure you get your favourite varieties. But garden centres and online seed merchants will still have seed potatoes available in February, so don’t worry if you’ve only just decided you’d like to grow potatoes.

How many seed potatoes do you need?
On average, 1 lb. of seed potatoes should yield about 10 lb. of potatoes. One lb. is about 5 – 8 tubers.

Chitting potatoes

What does chitting potatoes mean exactly? Chitting is a method of giving the potatoes a head start before you plant them; particularly useful for early varieties. Standing the seed potatoes in egg boxes helps to keep the chits or shoots safe from being knocked off.

Keep the tubers frost free, and in a light airy place to encourage strong growth of the shots. Wait for the shoots to appear, which could take up to four weeks for them to be ground ready.

Chitting potato tubers is not essential, so if you don’t have room, don’t worry too much. Earlies benefit more than main crop potatoes as the idea is to get them grown and harvested as soon as possible.

One potato, two potato

It is possible to cut the seed potato tubers into pieces, as long as the pieces have at least one eye each. An “eye” is a bud that grows into the new potato plant.

You can plant whole potatoes or pieces with multiple eyes, but generally speaking, the more eyes per piece more, but smaller potatoes. Whilst one or two eyes per piece fewer but larger harvested potatoes.

If you decide to cut your seed potatoes into pieces, cut them about 2 days before you plan to plant them. This allows a callus to form over the cut edge, which helps to prevent rotting and soil borne diseases.

Growing Potatoes in Potato Sacks

For details on this technique, check out our blog posts below. The same method applies whether you’re growing new potatoes or main crop potatoes.

It can be fun to get some seed potatoes of Swift, one of the earliest early potato varieties, and start them off in January in a potato grow sack in your greenhouse. (Which doesn’t have to be heated if it’s insulated) You could have your crop of first earlies almost before you’ve planted any outdoors.

Garden Teacher Tip

A thought to bear in mind for years where we’ve had a wet winter. If you have heavy clay soil, it may still be very wet when your chitted potatoes are ready for planting. Why not try planting some of your potato tubers in potato grow sacks as well as in the ground? This way, you’re hedging your bets, so that if the wet conditions lead to rotting due to poor drainage, you’ll still have a crop of potatoes. This may be even more important to you if you’re growing heritage potatoes.

Growing Potatoes in Rows

A traditional cultivation method and still useful where you have the room. See blog links below for this method, for crop rotation and other methods for growing your own vegetables.

If you’re planning on growing your potatoes in rows, then you’ll need to dig a trench or drill about 6” deep. This allows you to cover the tuber with about 4” of soil.
The soil should ideally have a pH5-6, so slightly acidic and be rich in humus. If you weren’t able to dig in compost to your soil in the autumn, then do so as you dig your trench.
Plant the tubers in the base of the drill, about 12” apart for earlies, 12-16” for second earlies and 15-18” for main crop varieties.

The following three methods are all good. I’ve used all of them in various gardens and on my allotment: –

Growing potatoes in rows – Method #1

Cover the seed potatoes by using a rake or hoe to draw the soil over them and form ridges over the rows.
Provided soil is moist you shouldn’t need to water at this stage.
The first shoots should emerge from the ridges after 3–4 weeks, depending on which type of potato you’re growing. The rows should be ridged up again to cover the shoots
Earth up two to three times as the foliage reaches approximately 6-9 inches in height. This stops any potatoes that grow near to the surface from turning green and inedible.

Growing potatoes in rows – Method #2

A less labour intensive method

Cover the seed potatoes by using a rake or hoe to draw the soil over them and form low ridges over the rows. This is to help you to remember where you’ve planted the potatoes so it is only a low ridge.
Provided soil is moist you shouldn’t need to water at this stage.
Now cover the whole area where there are planted potatoes with black membrane or plastic. This is to prevent light getting to the tubers and acts in the same way as continually earthing up the ridges.
Using membrane or plastic across the whole area also reduces weeds – and therefore weeding. The membrane is permeable to water whereas the plastic isn’t, but should retain more moisture, assuming the soil was wet initially.
The first shoots should emerge after 2-3 weeks, depending on which type of potato you’re growing. You’ll need to watch out for these, as you’ll then have to cut holes for the top growth to come through the membrane or plastic.

Growing potatoes in rows – Method #3

A more ‘environmentally friendly’ version, if you like. The basic method is the same, what differs is the cover. Instead of membrane or plastic, use –

a thick layer of grass clippings and shredded garden material. This latter should be disease free of course
cardboard, possibly a couple of layers depending how thick it is. This also acts as a weed suppressant
or use a combination of the two to give you enough ‘blanket’ material

Garden Teacher Tip

Whichever method you use, it’s a good idea to the space between the rows as the potatoes will be in the ground for some time. Sow quick growing salad seeds such as rocket or baby lettuce in between your rows, they’ll be harvested well in advance of the spreading potato foliage.

Planting to harvest times for Potatoes

Early potato varieties take about 100-110 days to mature
Second earlies take about 100-120 days
Main crop potatoes take about 120 -140 days

Pests and Diseases

Blight, eel worm and slugs are the main problems. Main crop potatoes are more prone to blight than early varieties. Growing potatoes in a sack or container makes slug control easier.

How can we reduce the likelihood of losing our own potato crops to late blight? The two easiest ways are: –

only buying and growing certified seed potatoes
growing early potatoes which are lifted before late blight is prevalent

Harvesting and Storing your home grown Potatoes

Basically, you harvest or dig up your potatoes when the foliage turns yellow and dies back. Whether you use a fork or a spade you’re almost guaranteed to spear and cut some of your crop. Don’t worry, the potatoes are still good, just use them straight away.

In another blog later in the year, I’ll look at methods for storing your grow your own fruit and vegetables. Both traditional and modern methods, appropriate for the domestic gardener where time and space may be limited.

Whilst I had very little to store in my first year in the new garden, I’m hoping and planning to need a fair bit of storage space in years to come so may need to be even more inventive!

And finally

For further gardening advice and inspiration, ideas for edible gardens and more, check out Plews Potting Shed blogs, including the selection below and our monthly Tipsheet . You could come and find us on Instagram – @plewsgd Pinterest and Facebook too.

And on that note, you can have a peek at my new garden in the (new) Instagram account @spitfiresandslowworms

If you’d like some personal help, we offer a mix of practical sessions and theory in our bespoke Gardening Lessons and Courses. There’s a blog link below plus a pdf download with more info

In the meantime, get chitting!