Growing Potatoes Organically in Cumbria

Many of our potatoes today originate from potatoes from Bolivia. These potatoes were capable of growing on the snowline of mountains at very high altitudes. They survived through these cold conditions because the foliage was covered with fine hairs. This gave the leaves an insulating layer to protect them from frost. Potato breeders are inter-breeding these old original potatoes with our new varieties to get the best taste and also better frost resistance. Another benefit of the layer of hair on the leaves is increased resistance to 'blight', the major potato disease. Blight is an airborne disease where the blight 'spores' are blown by the wind onto the leaves of potatoes. Cut and burn the stems (shores) when blight attacks, the potatoes should be okay for a couple of weeks in the ground.

An enormous selection of varieties is available. These vary considerably in shape, size, colour, cooking and eating qualities and resistance to common potato pests and diseases. It is worth trying different varieties, to see which best suits your soil and your tastes. Whatever you choose, grow them organically - and they'll taste even better. To avoid introducing pests and diseases, plant good quality, organic certified seed potatoes.

When and how to Plant Potato Seed

Potatoes are grown from 'seed' potatoes which need to 'sprout' before planting. Potatoes are grouped according to their season of harvest i.e. earlies, second earlies and maincrop. In general, early varieties are lower yielding, require less space and escape many of the diseases that effect the later harvested maincrop.

First purchase the 'seed' potatoes in mid-January to mid-February. These are widely available from seed catalogues or at Potato Day events. Look for seed potato which is organically certified and is free from disease and then select

healthy looking examples about the size of an egg.

 
Chitting

Treat seed tubers carefully. Place them in a clean box or tray – old egg boxes are ideal – with the 'rose' end (the end where the tiny buds can be seen) upwards. Keep in a dark, dry place until you see tiny shoots appearing, then move to a cool (8-10°C), light place. This process, known as 'chitting', encourages the tubers to produce strong, sturdy sprouts and gives an earlier maturing crop. Tubers can safely stay in their trays until planting conditions are right. If the sprouts appear too early for planting the potatoes outside, simply rub them off cleanly and they will re-sprout in a couple of weeks. It has been known for the sprouts to be removed five times without any ill effect on the sprouts which will replace them.

The potato seed should be positioned so the sprouts are uppermost and the 'stalk' end (where they were severed from the parent plant) is at the bottom. Sometimes this is a bit difficult to judge but if you get it wrong and the potatoes sprout from the bottom end, simply rub off the sprouts and turn the potato to the correct position.

As the potatoes produce sprouts, remove all but the topmost four to ensure that they receive all the goodness of the seed potato. The ideal sprout length at planting time is 2.5cm (1in) although this is not critical. What is critical, is that the sprouts are green and not white coloured. White sprouts are caused by not enough light.

Soil preparation

In late Autumn, dig well-rotted manure into the top 30cm (12in) of soil. Use around one barrow load to 10sq.m of ground. If manure is unavailable, home-made compost, a general organic fertiliser (plus leafmould for water retention), or a proprietary brand of bagged manure can be used. Never add lime before planting potatoes, as this can encourage scab. The ideal position for potatoes is a warm and sunny site with little or no shade. Do not grow potatoes in the same location for two years in succession as this will increase the risk of disease. For the same reason do not plant potatoes where tomatoes were grown the previous year. Both are from the same family and will readily transmit diseases to each other.

Early to mid-April is the ideal time to plant the sprouted potatoes in the open ground. Plant 'earlies' about 30cm (12in) apart from each other, in rows which are 60 cm (2ft) apart. Plant maincrop potatoes about 35cm (15in) apart, in rows which are 75cm (2ft 6in) apart. Where you are planting more than one row, the rows should (ideally) run from North to South to allow each plant its full share of sun.

Dig a trench about 10cm (4in) deep, placing the potatoes in it with the sprouts pointing upwards. Hand fill the trench over the potatoes trying to avoid damaging any sprouts.

 
Caring for Your Potatoes

Frost damage is the first concern in the early stages. If shoots emerge above the soil level and frost threatens, draw a little soil from the bed edges over them.

After the potato plants have grown to about 20cm (8in) pull up the soil in between the rows around the plants leaving a few centimetres still showing. Repeat the exercise in two to three weeks time.

During the growing season, ensure that weeds are removed and apply some fertiliser again around mid-June. A month or so after planting, the dense foliage of the plant should then block out sufficient light to deter all but the most vigorous weeds.

How to Harvest and Store Potatoes

Potatoes are ready for harvest when the foliage first starts to die and turn yellow. Early (new) potatoes can be lifted earlier (no earlier than June) to get the very tastiest potatoes. In this case, harvest them about a week after the potato plant flowers first appear. New potatoes only produce a couple of handfuls of potatoes per plant, so dig up the whole plant.

Maincrop potatoes will be ready for harvest in mid-Autumn (start of September at the earliest). For all potatoes, dig them up from the side of the ridge (a fork or spade are both fine) to avoid damaging the potatoes.

The foliage can be placed on the compost heap only if it is completely free from disease - if not, burn it. If you don't need all the potatoes from a plant at one time or if you want a few early in the season, simply burrow around the roots with your hands and remove the potatoes you need. The remaining potatoes will continue to grow giving you a second crop.

Remove any soil clinging to the potatoes and leave them on the soil for a few hours to dry out – if they are stored damp, they will rot. Leaving them on the soil surface in the sun will harden the skin slightly, doubling the storage time - this is especially important for maincrop potatoes. Store the potatoes in boxes or sacks, checking them every few days, removing all but those in good condition. Damaged or blemished potatoes should be eaten immediately.

Some varieties you may like to try:

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