by Michael Smith (Veshengro)
Seed potatoes
There is absolutely no need to buy seed potatoes. The best results I have achieved, so far, have always been from (cheap) store bought potatoes that have chitted.
Earthing up
According to trials conducted by T & M when growing potatoes in potato bags or in containers, such as tubs and buckets, there is no need to earth up at all. All that is required is for the tuber(s) to be planted about 12 cm (that is 5 inches in old money) and then leave them to grow.
Nothing beats that freshly dug, earthy taste of your own home grown potatoes! Growing your own potatoes is not as complicated as you might think, particularly if you grow them in potato bags which can be gotten from Thompson & Morgan or other containers, such as tree buckets that often are thrown away during tree plantings. It is the perfect method for growing spuds in small gardens, patios or even on balconies. Potatoes growing in containers are also at much less risk of pests and diseases, and many things can be used as containers in which to grow potatoes.
“Chitting” potatoes
Seed potatoes, particularly earlies and second earlies benefit from 'chitting', which is the process of growing shoots on potato tubers prior to planting. The benefit is that this will produce faster growth and heavier crops.
You can start them off as soon as you receive them. Remove the seed potatoes from their packaging and lay them out in a cool, bright, frost free position. The tried and tested method is to set them out in egg boxes or seed trays. You will notice that the immature shoots are all at one end (called the rose end). Place the potatoes with this end facing upwards. By the time that you are ready to plant them, they will have produced shoots up to
25mm (1") in length.
There is one exception - second cropping potatoes do not require chitting and can be planted straight away.
Cutting Seed Potatoes
In fact, during the 2nd World War it was common practice to cut larger seed potatoes in half or even smaller divisions to make the seed potatoes go further. The cuts should be left to dry out for 3 or 4 days before planting in the usual way. Provided that each piece has an eye or two for the new growth to develop, these tuber divisions will still crop well. Nowadays, seed potatoes are cheap and widely available so there is generally no need to do this unless you receive particularly large seed potatoes with lots of eyes.
Having just talked about “seed potatoes” and many seed merchants obviously keep telling us that we need to have “seed potatoes”, ideally, as far as they are concerned, bought from them, in order to get a good crop. In fact you do not have to do that at all. Having tried it out once just for the heck of it I found that cheap supermarket potatoes that had chitted created a good crop in a container I have never bought any since.
In fact while I once had some supposedly – please note the stress on the word supposedly – blight resistant potatoes it was they that got the blight that year while all the ones growing from supermarket ones did not.
How to plant potatoes in bags or other containers
Growing potatoes in planters is the perfect solution if you want to grow your own potatoes but have limited space.
In the past, growing potatoes in bags or containers has always involved 'earthing up' potatoes as they grow, like one does in beds. But recent trials, as I already mentioned above, at Thompson and Morgan have shown that this is not at all necessary, so planting potatoes on your patio has just got even easier.
To plant up potato grow bags or containers in two easy steps:
Simply fill a potato bag – or any bucket kind of container such as one that would hold a couple of gallons – with good quality multipurpose compost to around 2.5cm (1") below the rim.
Carefully plunge a single chitted potato tuber into the compost with the shoots pointing upwards, to a depth of 12cm (5") from the soil surface. Gently cover the tubers with compost.
Now all you need to do is water them, place the potato bag in a bright, frost free position and wait for them to grow.
You may want to feed the potato plants every other week with potato fertilizer and water the containers when the compost begins to dry out. Containers do require a lot more regular watering that does an earth bed, for instance.
Harvesting potatoes
Now we are coming to the really important bit, for you are growing those potatoes after all to harvest and eat.
Harvest times will vary depending on the growing season and the size of tuber you want. However the table at the top of the page provides a rough guide for each crop type.
Start to harvest first earlies as 'new potatoes' when the plants begin to flower, approximately ten weeks from planting. It is worth having a gentle dig below the surface to check the potato sizes – If they are still too small simply leave them for another week or so, otherwise lift them and enjoy!
Maincrop varieties are usually left for at least two weeks after the leaves and stems, which are called haulms, have withered, to allow the skins to set. Cut down the stems with secateurs to just above soil level as the leaves wither and yellow, or if they show signs of blight.
Second cropping tubers are often called Christmas potatoes. These winter potatoes can be harvested as required from November, or left in the soil until Christmas. Cut down the foliage as the leaves wither and yellow, and protect them from frost by covering the containers with a thick layer of straw or moving them into the shed or greenhouse.
Storing Potatoes
After harvesting, set the tubers out in a dry, well ventilated position for a few hours to dry and cure the skin. Once dry store them in paper or hessian potato sacks in a dark, cool but frost free place. Avoid storing in polythene bags as potatoes will 'sweat' and rot.
Potato problems
Late Blight
Symptoms: Late blight is particularly prevalent during warm humid weather and wet periods in late summer. Dark brown blotches appear on the leaves, particularly towards the leaf tips and edges. White fungal spores develop around these lesions on the undersides of the leaves, and further lesions develop on the stems. Leaves and stems rapidly blacken and rot causing plant collapse. The spores are released on the wind and quickly spread to infect neighboring plants. Spores may also be washed down into the soil where they can infect potato tubers causing a red-brown rot directly beneath the skin which slowly spreads towards the center of the tuber.
Remedy: Spray potato crops with a protective fungicide even before signs of blight become apparent. Begin spraying this potato blight treatment from about June, particularly when periods of wet weather are forecast and spray again after a few weeks to protect any new growth. If plants become infected they should be removed and destroyed. Where potato crops have already developed tubers then these can be saved by cutting away the foliage and stems. Leave the soil undisturbed for 2/3 weeks to kill off any lingering spores so that they don't infect the crop when it is lifted.
Slugs
Symptoms: Slugs cause damage to both the foliage and to the developing potato tubers. Damage is fairly obvious as the culprits are easily identified by the silvery slime trails that are left around the plant foliage and on the soil surface.
Remedy: There are a multitude of ways to kill slugs and snails including homemade remedies such as beer traps. The most common method is to use slug pellets or for the more organically minded gardener you can try nematodes or copper tape.
Potato Scab
Symptoms: Common Scab leaves corky lesions on the skins of potatoes and limits their storage potential. Whilst this disease does not affect the taste and can easily be peeled off, it does make potatoes less visually appealing. It is caused by a bacteria that is often present in manures and is exacerbated in limy and sandy soils, and under dry conditions.
Remedy: Common Scab on potatoes is best controlled by improving poor soil conditions with the addition of organic matter and by keeping potato crops well watered throughout the growing season. Use any infected tubers first and do not store them.
Eelworm
Symptoms: There are two types of Potato cyst eelworms - the golden eelworm and the white eelworm. Plant growth is checked and potato yields are reduced. The foliage of severely infected plants turns yellow and dies back early prematurely, often in conspicuous patches where the soil in infested with eelworms. The presence of Eelworm cam be confirmed by inspecting the roots of damaged plants, where minute pinhead sized cysts can be seen. They will be white, yellow or brown in color.
Remedy: There are no effective remedies to serious infestations other than to refrain from growing potatoes in infected soils for at least 6 years. Practice good crop rotation to prevent infestations building up in the soil. Eelworm resistant varieties are available but are not immune from attack.
Blackleg
Symptoms: Potato Blackleg is spread through contact and is particularly prevalent in cool, wet and poorly drained soils. This bacterial disease causes blackening of the stems, close to soil level as the stems begin to rot. Ultimately stems will collapse. Yellowing and browning of the leaves may also occur. Affected tubers display gray or brown slimy rot inside or may rot away completely.
Remedy: Blackleg generally infects individual plants rather than entire crops and does not spread between plants or persist in the soil. Remove and destroy any infected plants, improve soil drainage and plant blackleg resistant potato varieties.
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