Grow Potatoes for a Christmas Crop

, written by Benedict Vanheems gb flag

Harvested potatoes

For many vegetable gardeners the humble potato is the epitome of everything that’s good about growing your own: they’re fun to grow, exceptionally versatile in the kitchen and they’re pretty darn tasty!

Fortunately, the potato season isn’t over when the last of the summer spuds are harvested. Plant some seed potatoes in late summer and you could be enjoying a bonanza of earthy nuggets from late autumn right through to Christmas. Just imagine serving up your own tender new potatoes with the festive meal – what a treat!

Second Crop Potatoes

Potatoes planted in summer are called second-crop potatoes. Seed potatoes (potato eyes in the US) for second cropping are sold by garden suppliers and potato merchants anytime from mid to late summer. The seeds are exactly the same as those sold for spring planting, only these ones have been held back in a cold store to stop them developing any further; they’re literally in suspended animation.

You can save your own seed potatoes for second cropping by keeping some of your spring seeds back. Keep them on a cool, bright windowsill. Check the shoots periodically for aphids and plant them before they begin to wither.

If you’re thinking you could simply replant some of your summer-harvested potatoes, I’m afraid this will only meet with disappointment. Potatoes need a period of dormancy before they can sprout into a new plant, so in this case you really will need to start with genuine seed potatoes.

Potatoes in grow sacks

Planting Second Crop Potatoes

Second-crop potatoes take about three months to reach maturity. They are grown in exactly the same way as spring-planted potatoes with two important exceptions. First, the warmth of late summer means that second-crop seed potatoes do not need to be pre-sprouted – they’re primed to get growing without delay. Second, you’ll need to consider the risk of frosts later on in the growing cycle and take the necessary precautions to avoid damage to your plants.

The easiest way to grow second-crop spuds is in containers. A small pot just 30cm (one foot) tall and wide can hold one potato plant, while larger containers up to the size of a dustbin could hold up to four. Set the seeds onto a layer of compost or potting soil about 10cm (4in) deep, or deeper if your container is particularly tall. Cover over with another 10cm (4in) of compost then add more compost as the stems grow, topping up 5-10cm (2-4in) at a time until the top of the container is reached.

Keep containers well watered because the compost can dry out quickly, even in wet weather. Apply an occasional feed of liquid fertiliser (home-made fertilisers are great for this purpose).

Planting potatoes in a trench

If you want to grow potatoes in the ground first consider how much of the growing season is left. You need to allow enough time before the temperature drops and growth slows right down.

If time allows you to grow your spuds in the ground, pick a warm, sunny spot to ensure the quickest growth and the best chances of success. Position the seed potatoes 30cm (12in) apart along the bottom of trenches spaced at least 60cm (24in) apart. Cover them over then once the stems reach about 20cm (8in) tall, begin earthing up by drawing the soil up around the stems to create ridges. This creates more ‘room’ for the developing spuds to grow into (container potatoes are topped up as they grow for the same reason).

Protecting Potatoes from the Cold

Containers have the obvious advantage of being portable, so when cold weather threatens it’s easy enough to move plants completely under the cover of a greenhouse, polythene tunnel or conservatory. You can also protect plants against light frosts by wrapping the container in layers of corrugated cardboard or bubble wrap.

Potato foliage can be kept snug with an insulating layer of fleece, removed during the day to allow maximum sunlight penetration.

Harvested potatoes

Harvesting and Storing Second Crop Potatoes

The moment of truth is when the leaves start to turn yellow and die back. At this stage cut the foliage off and put it on the compost heap. Now prepare to unearth your spuds – a joyous moment indeed!

Container-grown spuds can be upturned and the compost torn apart to reveal the tubers. If you’ve grown them in the ground, use a border fork to carefully dig the plants up, starting some way from the plant to avoid accidentally spearing your hard-won tubers.

Potatoes can be enjoyed immediately, but if you want to have a shot at keeping them until Christmas leave the spuds untouched in containers, keeping the compost barely moist then unearth them when you are ready. You should have no problems holding them back for an extra month or two provided conditions remain cool but frost-free.

Whether or not you choose to leave potatoes in the ground depends on how cold early winter is in your part of the world. In temperate regions, little more than an extra pile of earth strewn over the top of the rows should be enough to provide an additional layer of defence against occasional frosts. If winters are severe or your soil is wet and heavy, then you’re safer lifting all of the potatoes to pack them into boxes of coarse sand kept in a frost-free place.

If you thought growing potatoes was hugely satisfying, second-crop potatoes will prove even more so! Give your holiday season dinners a home-grown boost and try them for yourself.

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Comments

 
"I looked around without success for second crop seed potatoes by contacting the companies that I usually get seed potatoes from in the spring. Would like to have the names of any seed companies that seed seed potatoes for planting a second crop."
Kate on Sunday 22 January 2017
"Hi Kate. Which country are you in? Here in the UK the seed companies usually advertise second crop potatoes from about June or July onwards. "
Ben Vanheems on Monday 23 January 2017
"Hi we have tried growing potatoes in the sacks you can buy from local garden centers around the uk ! After weeks of carefully tending to the plants we at last came to the harvesting part ! When we tipped the bags out onto the ground it was very disappointing as each bag emptied contained very minute potatoes even though we had waited for the instructed period before cropping ! In total we managed to get a breakfast bowl of potatoes out of three bags ! All the instructions had been followed ! Could this be that the seed potatoes were bad stock or just bad luck ?"
S Green on Sunday 13 August 2017
"I found a garden centre that was giving seed spuds away, I don’t know if they were for spring planting or autumn planting But hey ho, they were giving them away No you couldn’t take bags of these spuds, just one bag of each variety I just took one bag of Marie pipers That will do me, I split the bag with my wife, she is planting them in the ground, I’m using a pot (Let’s see who gets the most spuds) ??"
Derrick on Thursday 22 August 2019
"Good luck to both of you Derrick. I suspect your wife will win! Let us know how you both get on."
Ben Vanheems on Monday 26 August 2019
"Hello! Thanks for this great article! I am interested in sowing 10lbs of potatoes for the first time, but find myself confused by the early season, mid, late season labels. Will the type of potato planted matter for second crop? It is June 15th and if I order today I can potentially have all the potatoes in ground by the 20th/25thish depending on arrival time. Some articles say that if it is too hot the potatoes will rot inside? If you could shed some light on that I would really appreciate it; thank youu! "
Nina on Sunday 14 June 2020
"Hi Ben Yes the wife did win, we both had a great crop of spuds though My wife must have left a couple in the ground, because there are several sprouting nearly a year later She is as pleased as punch about it as well So growing them in ground does prove better than in pots, I don’t know about sacks or containers though Thanks again "
Derrick on Monday 15 June 2020
"Hi Nina. In theory I think any potato variety held back could be grown as a second crop of potatoes. However, speed is of the essence because you want most of the growing done before the return of colder weather. For this reason it is usually early varieties of potato that are sold for planting in summer. Check with suppliers - they usually sell potatoes specifically for planting in summer and will be able to recommend the best varieties for this. Yes, you don't want your potatoes to get too hot. If it is quite warm where you are, you may get better results planting them in the ground where the soil temperature is a little more consistent and it's easy to keep plants well watered and, hence, cooler. Heat can at the very least stop plants from producing many tubers. Derrick - Thanks for the update. And your experience of growing potatoes in the ground does concur with what many people say. There's simply more 'room' for the tubers to grow and the conditions will be more consistent."
Ben Vanheems on Monday 15 June 2020
"Hi, just got some second drop Charlotte seed potatoes. Should I plant them in the same spot as my earlies, which I have now harvested ? Or should I find a different spot which has not had potatoes this season . "
Ian on Monday 29 June 2020
"Hi Ian. I would find a new spot, as you don't want to run the risk of passing on any problems from the last crop to this new crop."
Ben Vanheems on Monday 6 July 2020
"Great article. I started my second crop mid August, in pots as you suggested, they were fingerlings bought from store for consumption. I know this is a no-no, but with the pandemic I did not want to run out of potatoes....I kept them in a paper bag for 2- 3 months each sprouted and sprouted, and shrivelled. I put them in the pots and within a few days leaves appeared. I covered all with remay thinking that the extra heat may hasten growth. After one month I put in extra soil as you suggested. I thought fingerlings would be a good choice as they are small....I won't know until harvest but I wonder was this a good choice ? I hate the idea of harvesting as did one of your subscribers to find not much. I could surround them with glass windows as the temperatures drop, still in high teens, British Columbia, Canada...thank you for your ideas"
Amelie Morton on Saturday 19 September 2020
"Hi Amelie. It's hard to know what variety of fingerling potato you have, as there are a few. But this does seem like a good choice for growing this way. Use any method you can as the temperature drops to keep them relatively warm. Surrounding them with glass, to create a miniature greenhouse environment, would certainly work, but you'll need to be sure to ensure enough ventilation and potentially remove panes of glass on warm days so that the temperatures don't soar too high. I'm not sure where you are in BC, but if you are near the coast you at least have a lovely mild climate, without the plunging temperatures further inland. This would certainly help."
Ben Vanheems on Monday 21 September 2020
"What a fine comprehensive article - precisely what I was lookuing for. Thank you.. (We live in Suffolk, where I have brought the Irish custom of planting Maincrop on St.Patrick's Day.)"
Joe McCann on Friday 10 September 2021
"Hi Joe. Thank you for your kind words. St Pat's Day might be a little early in some years, owing to cold weather. But clearly it's working for you. "
Ben Vanheems on Monday 13 September 2021
"Hi Ben, I will be planting potatoes in large pots in late winter. Is there a minimum depth of soil BELOW the seed potatoes when I plant them? I want to have as much room in the pot above the soil to layer sugar cane mulch over the top as the stems grow. The pots are 33cm deep and 38cm across the top. Thanks once again, Natalie."
Natalie on Sunday 23 April 2023
"Hi Natalie. The usual recommendation is for a depth of about 15cm, but I reckon you could have as little as 10cm in the bottom given the relatively small size of your pots."
Ben Vanheems on Tuesday 25 April 2023
"Hi Ben….Aug 02 ……I have just planted seed potatoes which have been dormant since middle of July and have now been chatted and planted in raised beds….my thoughts are that when I harvest this crop October time…I want to pick out a hundred potatoes of the harvest and make my own seed potatoes for next May…that way I don’t have to buy bags of seed potatoes again….is it as easy as it sounds.? Look forward to your reply…Thanks Dave"
Dave Freeman on Friday 4 August 2023
"You should be able to do that, yes. But they need to be from completely clean/healthy plants (to avoid spreading disease) and they will need a chilling period over winter to set them up for the next season. Just keep them somewhere cold but frost-free so they experience a proper winter, ready to re-plant in spring."
Ben Vanheems on Friday 4 August 2023

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