Originally bred behind the “Iron Curtain”, where growers had no access to fungicides, and winters were long and hard. These blight-resistant potatoes were selected for their outstanding resistance and storage capabilities.
Our recent survey reveals customers’ top considerations when they purchased their seed potatoes:
- The Taste
- Potatoes with a Resistance to Blight
- The Uses of the potatoes e.g. best for mashing, roasting etc
- Potato Storage
What is Potato Blight?
Sometimes known as ‘water mould’ it is caused by the fungus-like organism Phytophthora infestans, which oddly, botanically is more closely allied to seaweeds than fungi! It does however perform in a similar way. Spores survive the winter in infected potato tubers left in the soil. Home saved tubers from an infected crop may also develop the disease when planted. That is why it is always best to start with new seed potatoes from a reliable source each year.
The initial infection can come from a local source but the spores are also blown by the wind and travel for many miles. Plants are infected when the spores land on wet foliage and the spread is rapid throughout the crop when conditions are warm and moist. Rain washes the spores from the leaves down into the soil where they infect the tubers.
Symptoms of blight
Dark brown round patches appear on leaves and spread quickly, rotting the whole leaf. Stems are also infected and reducing the foliage to a rotting mass within a few days.
Tubers show dark and sunken areas on the surface. On the inside brown rot starts just under the skin and eventually turn the tubers into a wet and foul smelling soft-rot. Seemingly healthy tubers may rot later when in store.
Prevention and Control
- Plant certified good quality tubers from a reputable supplier
- Grow early varieties where you are more likely to harvest a good crop before blight strikes
- Choose a blight-resistant variety
- Water plants early in the morning and avoid wetting the foliage
- ‘Earthing up’ or mulching the soil with thick layers can reduce tuber infection
- If blight strikes, cut away all infected material immediately and burn
- Do not wash potatoes that are to be stored. Remove any infected tubers and check stored potatoes regularly and remove any rotting tubers.
How to grow blight resistant potatoes
Unpack your seed potatoes and place them in trays (an egg box works well or you can use a wooden tray) in a light, airy frost free place to develop sprouts prior to planting. This will enable your seed potatoes to grow much faster once they are in the ground. Pre-sprouting is a process called chitting (want to know about chitting, see our guide about whether to Chit or not
Dig a trench about 10cm (4″) deep, using our Garden Ridger is the easiest way to do this. Place the seed potatoes at the bottom with the sprouts facing upwards. Fill the trench to cover your seed potatoes and a top dressing of Potato Fertiliser can be applied to boost growth and cropping
As shoots emerge it is important to “earth up” (cover with soil) to protect them from frost, which will cause the shoots to blacken and delay cropping. During prolonged periods of dry weather, you will want to water plentifully to enable tubers to form. When stems have grown to 25cm (10″) above ground level they should be “earthed up” again to prevent the tubers near the surface turning green.
When to lift will be dependent on the type of potatoes you have planted, please see the table below. Lift early potatoes when the flowers begin to open and the tubers are the size of large eggs. Leave maincrop potatoes for at least two weeks after the leaves and stems have withered. You can then cut the stems just above soil level to prevent disease such as blight getting into the crop. Lift gently from underneath with a Potato Fork or with our Potato Harvesting Scoop. Lifted potatoes should be left on the surface of the soil for a couple of hours to allow the skins to cure before you store them in paper or Hessian Sacks. Potatoes stored in plastic bags will sweat and begin to rot very quickly.
Our Blight Resistant Potato Collection
We have five varieties of blight-resistant potatoes that combine excellent taste with blight tolerance. A deliciously hardy selection, they are particularly useful in the recent British summers.
Setanta: Red skinned maincrop with perhaps the highest blight tolerance of any potato. Superb tasting and easy to grow. Ideal for a jacket, roast and chips. Maincrop.
Nicola: Colour – yellow. Shape – long oval. High yielding variety, stores well. Tasty ‘new’ potato variety. Waxy flesh. Salad.
Cara: Makes very tasty mashed and baked potatoes. Maincrop.
Colleen: A high yielding variety producing round-oval tubers that have white skin and light yellow flesh. First Early.
Sarpo Mira: Red, oval, unprecedented blight resistance, good slug resistance, vigorous weed suppressing foliage and it grows well in a wide range of soils. Maincrop.