How to grow potatoes in bags - thompson-morgan.com

How to grow potatoes in bags - thompson-morgan.com

When to grow potatoes

Potatoes are normally planted in March for harvesting throughout summer and autumn. They can also be planted in August/September for Christmas new potatoes (these are also known as Second Cropping Potatoes). Use the table below as a general guide on when to plant potatoes.

Not sure what the difference is?

Cropping Type	Planting time begins	Final planting date	Harvest from planting date
First early potatoes	End of February	Late May	10 weeks
Second early potatoes	March	Late May	13 weeks
Early maincrop potatoes	March	Late May	15 weeks
Maincrop potatoes	March	Mid May	20 weeks
Second cropping potatoes	Early August	End of August	11 weeks

...

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 neighbouring 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 centre of the tuber.

Remedy: Spray potato crops with a protective fungicide such as Bordeaux Mixture 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.

Click here for more information on potato blight control.

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 colour.

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 grey 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.

Growing potatoes in the ground

If you're lucky enough to have a bit more space why not try growing potatoes in the ground? Click here to find out how to grow potatoes in the ground.