Growing Your Own Perfect Potatoes
23 February 2023
One of my earliest memories of growing vegetables has to be as a young lad following behind my father in April dropping seed potatoes into holes he had dibbed into the ground. He was using a dibber that had been cut from an old tree by his father whilst pruning one year. This dibber had a side branch that was just at the right height for putting his foot on and pushing a hole 10-15cm (4-6in) deep into the ground. It was my job to drop the seed potato in before the hole caved in.
Later in the year it was also my job to help pick up the potatoes, that Dad had lifted with his trusted flat tined potato fork, which was supposed to lift the tubers cleanly without spearing them; it worked most of the time.
These were happy days and certainly got me hooked on vegetable growing. Like most gardeners Dad had his favourites to grow each year, these were Arran Pilot a first Early and Desiree a main crop that stored well for the winter; all are still available and are just as popular today.
If you visit any vegetable garden or allotment you will always see a few rows of potatoes growing, what other vegetable can you eat almost every day with one meal or another? Thinking about it there are not many vegetables that if you wished you could eat for Breakfast, dinner and your tea.
If you had room you could grow over 40 different varieties that are freely available from mail order companies. This choice enables you to grow different potatoes for different culinary uses. Gone are the days when potatoes were only used boiled, or as chips. Now there are varieties that are good mashed, baked, roasted or even eaten warm or cold with salads as well as using them in many other culinary dishes.
As well as choice of varieties being improved, with modern growing techniques you not limited to the vegetable garden because you can even grow potatoes in bags, or barrels on the patio. Or you could try to extend the growing season, so maybe this year you will be harvesting you’re own new potatoes for Christmas?
Understanding the catalogue Jargon
Most seed catalogues will sell their seed potatoes under the heading of being Certified Scottish Seed, which means they have been grown in Scotland, and kept pest and disease free and have been given an approved seed passport so they can be sent anywhere in Europe. Scottish Seed potatoes are considered the best seed in the World, for the cleanliness of its stock and Quality of the seed Potatoes produced. The next best seed is British and Irish produced, because like the Scottish seed they also follow stringent cleanliness of stock controls.
Occasionally you will see Seed Potatoes for sale from other continental sources, but many mail order companies are now moving away from these to help safeguard the potato industry against the devastating Brown Rot and Ring Rot infections possible from these continental sources.
Potatoes are usually listed under there maturity dates First Early, Second Early, Early Maincrop and Late Maincrop. This tells you that the First Earlies will be the first to Plant and the first to Harvest and The Late Maincrops will be the last, the others are fitted in-between. To ensure you have Potatoes all through the season it is best to grow a small amount of First Earlies, Second Earlies and Maincrops . First Earlies are best eaten as New Potatoes or if lifted and Stored eaten first, where as Second Earlies and Main crops both will store well, with the Maincrops storing for the longest.
Seed Potatoes are sometimes sold as just seed potatoes or sometimes as Organic seed potatoes. Organic seed Potatoes are varieties that have been grown completely organically and are certified by the organic Soil Association, confirming they have been grown with no use of chemicals. The organic range of Potato varieties sold is often more limited than the non organic certified seed potatoes . The non organic varieties may have been sprayed with chemicals at some time in there growing season but this will have had no effect on the tubers that you plant and these come in a wider choice of varieties and can still be grown organically by the home gardener if they wish.
You will sometimes see potatoes sold as Second Cropping Potatoes . These are Potato tubers that have been kept in cold store for planting during the summer. This growing technique has increased in popularity in recent year and enables you to extend the cropping season. Later I will explain in more detail how to grow this type of potato.
To Chit or not to Chit ?
There has always been a big debate about whether you need to chit seed potatoes or not. I have always laid out my seed potatoes to chit and I believe you get bigger and better crops from Earlies and Second Earlies that have been chitted against ones that have not.
If you are growing Maincrop varieties I still think it is worth laying them out, so that the tubers can be checked over for any diseased or damaged tubers but not all Maincrop varieties will chit in trays. Quite often the planting time will arrive and there will be no visible shoots on the main crop tubers, these can still be planted straight into the ground and as if by magic they will start to produce shoots. For some reason certain main crop varieties do not like chitting in trays.
Chitting is a term used which basically means once the seed potato tubers arrive they should be taken out of their net bags and laid out in seed trays or egg boxes in a cool but frost free place in good light. I find laying the trays on the benches of a frost-free greenhouse or in front of a window in a cool spare bedroom indoors is ideal.
Seed potato tubers are usually delivered by mail order companies from January onwards or are available in garden centres around the same time. Once laid out after a few weeks they will start to shoot or chit from the potato eyes. If you have placed your tubers in a light place you will get short, sturdy dark green shoots, these are ideal. What you don’t want are long and leggy white shoots, as these will give very poor results.
Planting Guide
As a general rule Potatoes can be planted from the End of February to Early May. For the Best results, provided weather conditions allow, follow this simple Guide of When to Plant and for how long before you will be able to start harvesting your crops.
First Earlies can be Planted From End of February to Late April. Harvest approximately 10 weeks from Planting.
Second Earlies plant from March to Late May. Harvest approximately 13 weeks from Planting.
Early Maincrops plant from Mid March to late May. Harvest approximately 15 weeks from planting.
Late Maincrops plant from Late March to late May. Harvest approximately 20 weeks from Planting.
Planting Distances
The various maturity dates of potatoes also determines the planting distances they require to get the best possible crop when grown in the ground.
First Earlies are best planted 30cm (12in) apart in the row and 60cm (2ft) between each row. You can also grow First Earlies in large pots, spud tubs or potato barrels in a frost-free tunnel or greenhouse early in the year for an extra early harvest of new potatoes.
Second Earlies are best planted 37cm (15in) apart in the rows and 60-75cm (2- 2 1/2 ft) between each row.
Early and Late Maincrops are best planted 45cm (18in) apart in the rows and 75cm (2 1/2 ft) between each row.
Planting and growing on
In the autumn make sure you add plenty of organic matter to the Soil where you are going to plant your seed potatoes that spring, this can be incorporated whilst winter digging. It is important that potatoes are grown on fresh ground each year making sure you have a strict crop rotation of a minimum of 3 years, as this will help stop the build up of soil borne pests and diseases and will prevent your ground from becoming sick of potatoes which in time would affect the quality of your harvest.
Potatoes like to grow in a fertile soil, so if you are adding manure to the ground, make sure it is well rotted, if possible at least 3 years old. The danger of adding too much fresh, hot, rich manure is the crop of potatoes could appear to be growing well producing plenty of lush green tops, but alas they produce very few tubers.
Once spring arrives I like to pull my ground down with a three-pronged cultivator and a rake, so the soil is roughly level.
Unlike my father’s method of planting with a dibber, I have always preferred to plant my potatoes in shallow trenches. I like to dig out trenches approximately 15cm (6in) deep with a spade, then put a layer of compost in the bottom. The compost I use is either well rotted home made compost, made from garden waste, or old compost which I have saved from plant pots that were filled with summer bedding the previous year. By placing compost at the bottom of the trenches gives the potatoes a softer environment to grow in, resulting in cleaner better quality tubers to harvest.
Before placing the tubers in the trench I like to sprinkle some Growmore or Potato Fertiliser at a rate of 60gm per square meter (2 oz per square yard) to the bottom of the trench over the compost and over the soil that I removed from the trench.
The trench is now ready to have the tubers spaced out along it at the required planting distance depending on the type I am planting. I am always asked if I reduce the number of shoots per potato when planting. I personally have never seen any benefit of reducing the shoots to 2 or 3 per tuber, because I always think if you leave them all on and 1or 2 were broken by accident when back filling all is not lost, so I have always left them all on, plus I think the more shoots the potential bigger crop you can achieve.
Once the tubers have been spaced out I then carefully back fill the trench with the remaining soil, then I lightly tread along the trench, to firm the ground then I rake it level.
Alternatively if you wish to follow my father method of planting, you can prepare the soil in the same way, without taking out a trench and plant your tubers with a long dibber or a trowel. Once planted in this way, you just rake the soil into the holes. This method works very well if you are on light soil, like my fathers garden used to be. But if you are on heavy land, I believe the best quality potatoes come from those planted in trenches.
During the early spring, you will notice the green shoots poking through the soil surface, as they appear they will need moulding or earthing up. I have found that the best tool for doing this job is my Swan neck hoe. As the shoots emerge I walk down in-between each of the rows and pull up the soil around the sides of each Potato. This is a job that needs to be done several times through the early part of the season, each time making the potato mounds or ridges a little higher.
The main reasons we earth up the potatoes is it will protect the young frost tender shoots from being nipped off or blackened by any frosts that may be forecasted. But more importantly the soil will help stop any light from reaching your Potato crop as it matures, because if this happens it will make the tubers turn green making they useless to eat.
Before the plants are too large to walk through and just before your last earthing up, I like to give a top dressing to the soil in-between the rows with the same Growmore or Potato Fertiliser at a rate of 60gm per square meter (2 oz per square yard) as used at planting. But make sure you keep this fertiliser off the foliage as this can cause scorch to the leaves.
During the summer keep your potatoes well watered if the weather is very hot and dry, this is important because water will help the tubers swell. Lack of water will result in lots of smaller tubers rather than large tubers suitable for storing.
During the growing season make sure you keep the plants clean from weeds, this is especially important during the early stages, because as the plants grow the foliage will meet in-between the rows and will help suppress any weed growth saving you a job.
Growing Second Cropping Potatoes
Second Cropping Potatoes are Potato tubers that have been kept in Cold Store until July, and then sent out by mail order companies direct to the gardeners for planting almost immediately. As the tubers have been cold stored as soon as they are planted they will start in to growth very quickly. Growing this type of potato helps you extend the growing season, giving you the chance to harvest a late crop of new potatoes.
If you are planning to plant these tubers outside they are best planted from the end of July up to the middle of August. If you are planting in containers under glass or in a polytunnel then planting can be delayed until the end of August at the very latest. Planting any later than this will give very disappointing results.
When the tubers arrive there is no need to chit them, they can be planted straight away. Although some gardeners like to plant them outside I prefer to plant them in barrels or spud tubs as you can move them undercover if the early autumn weather becomes unfavourable.
Once planted they will rapidly grow, and within 10-11 weeks you should have some ping-pong sized tubers ready to harvest. Tubers can be harvested as required or left in the compost until a little larger. On cold nights as they are growing protect them from frost with some fleece.
As the foliage starts to yellow and wither cut this down to ground level with a pair of secateurs, do this also if you get a late attack of blight on the foliage. If you leave some of the tubers in the pots or in the ground you can cover them over with straw or sacking, this will give them some frost protection and you can lift these as new potatoes for your Christmas dinner.
One word of warning the longer the tubers are left in the containers or in the ground, there is more chance of them being attacked by soil borne pests like slugs or wireworm. I always add some form of slug control around my plants as they are growing and are waiting to be harvested to offer some form of protection.
I think this crop is certainly worth giving a try, because it is very satisfying and can look very impressive serving up home grown new potatoes for your Christmas lunch.
Potential Potato problems
A few pests in the garden can attack potatoes, some can cause more damage than others. Aphids can affect the growth of young foliage and can spread virus to your crop, so it pays to be vigilant and spray with a suitable insecticide as soon as they are spotted.
Slugs can cause problem eating into the underground tubers. This is not the normal slug that can be spotted above ground, but the keel slug. These are best controlled by Nematodes, a biological control for slugs that can be watered into the soil and after 3 days they will start to seek out the slugs and start to kill them. Alternatively using a Liquid Slug Killer chemical can also control them. There are also varieties that can be grown that also show good slug resistance.
Wireworm as a rule are not a big problem for gardeners, which is just as well because there is no chemical control available to the home gardener to use. I have found that the best method of control is to dig your plot in early autumn, and fork it over again in early spring to encourage some of your feathered friends to visit and feed on this delicious bird snack.
Most gardeners can avoid eelworm by operating a strict crop rotation plan. If however you find this to be a persistent problem in your area you could try growing some of the Eelworm resistant varieties .
A few diseases like Scab, Blackleg and Blight can also affect potatoes.
Scab on potatoes often occurs when they have been grown on ground that is alkaline or has had to much lime added to it for previous crops. Scab can be deterred by keeping plants well watered throughout the growing season or by growing common scab resistant varieties.
The diseases Black leg and Ring Rot are less common these days and is more likely to occur if you grow seed varieties that have been produced on the continent rather than from Scottish, Irish or British produced seed. There are no chemical controls for these diseases and the best way to avoid it is to only grow seed potatoes that have come from the UK.
The most common potato disease for gardeners has to be Blight. There are two forms of Blight; one is known as Early Blight or (Target Spot) appearing when the weather conditions are very hot. This form of blight is more commonly seen on early varieties. The Other blight appears when the weather conditions are very warm and humid. Both Blights show their symptoms on the foliage first in the form of brown or pale spots. If blight is not kept under control it will spread down into the tubers and turn them soft and make them go rotten. If your crop gets blight it can not be cured but it can be prevented by spraying your foliage with the a suitable fungicide at the first sign of the disease or better still when weather conditions are suitable for this disease to appear. If your tubers have swelled sufficiently and blight appears on the foliage, you can cut this off and bin it or burn it, to stop the disease from spreading down into the tubers. Do not put blighted foliage or tubers on the compost heap otherwise the disease may spread.
If you grow organically or you would just like to grow some potatoes that won’t need spraying against blight, you can now grow two of the best blight resistant varieties ever introduced. These were bred in Hungary by the Savari family who have been breeding and selecting for blight and virus resistance for over 50 years. They have developed the Sarpo varieties which are late main crop varieties like Sarpo Mira. These varieties are very strong growers and will produce strong dark green weed suppressing foliage up to 150cm (5ft) tall. In recent trials even if the foliage was to get an attack by blight it has been found that this will not travel down the stems and affect the tubers, so your harvest is always ok. In fact the foliage will keep on growing and will still be green in October until we get a frost. If you wanted to lift your crop and store the tubers before this, I advise you cut the foliage off at least 3 weeks before you want to lift and store your potatoes, this will allow enough time for the skins to set.
Ready to eat
Potatoes are ready to harvest as soon as they are big enough to eat, usually the size of a hens egg as new Potatoes, up until they are fully mature and are big enough to lift and store for winter use.
If you are looking for that first meal of new Potatoes, these are usually ready to harvest from the end of May.
If you want to harvest Early and Second Early varieties, this can be done from August onwards, once the foliage has died down and the skins have set. These will store ready for using first in the autumn or early winter.
Maincrops are usually ready to lift once the foliage has died down and the potato skins have set firm from late August through to October.
I always lift my potatoes with a flat tined Potato Fork just like my fathers, trying not to stab too many potatoes. I like to pick the Potatoes up in a Bucket as I go along each row, then I lay them out on an old cloth in the sunshine for 1or 2 hours until the soil has dried on the skins. I then rub off the majority of the dried Soil before putting them into Paper or Hessian Potato Sacks.
These sacks of Potatoes are best stored in a cool frost-free garage or shed over the winter. Make sure you keep an eye on the weather forecast and if frosty weather is forecast cover the sacks with an old carpet or blanket to keep any frost at bay.
Throughout the winter months I like to check my stored tubers at least once a month to ensure that I have no rotten or diseased potatoes within the sacks. If any are spotted
these tubers are removed, because if left unattended this rot can quickly spread to other tubers within the sacks.
With a bit of luck you will have enough stored potatoes to keep you going until it is time to lift some new potatoes once again.
By Andrew Tokely
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